TECHNICAL FIELD

This invention relates to a system for controlling counter steer in a vehicle. In particular, this invention relates to a system for controlling counter steer in a tilting vehicle.

BACKGROUND

Conventional tilting vehicles, such as motorbikes, motorised trikes, and‘narrow’ four-wheeled vehicles, can only be ridden safely if the rider makes good use of counter steer, and, at lower vehicle speeds, counter lean.

To negotiate a turn successfully, the combined centre of mass of the rider and the vehicle must first be leaned in the direction of the turn, and counter steering briefly in the opposite direction causes that lean. The rider's action of counter steering is also sometimes referred to as "giving a steering command”.

A key problem is that counter steering and counter leaning are counter intuitive, and it takes a very experienced rider to handle the vehicle appropriately at all times. For example, in an emergency it may be necessary to momentarily steer towards the very obstacle to be avoided, which is particularly scary when travelling at high speed. Furthermore, it can be difficult to regain control after hitting a slippery/oily patch in the road, or to withstand sudden crosswinds, especially for vehicles that are particularly susceptible to cross winds, such as vehicles offering full weather protection.

There remains a need for a more intuitive means of triggering counter steer and counter lean in tilting vehicles. It is an object of the present invention to address one or more of the above problems and/or at least one other problem associated with the prior art.

SUMMARY OF THE INVENTION

In general terms, the invention provides a means for controlling counter steer in a tilting vehicle. A steering controller is moveable to control both steering of one or more wheels of the vehicle and counter steering of one or more wheels of the vehicle. In preferred embodiments steering is controlled by movement of the steering controller in a steering plane (optionally rotation about a steering axis perpendicular to the steering plane) and counter steering is controlled by movement of the steering controller in a counter steering plane (optionally rotation about a counter steering axis perpendicular to the counter steering plane). The steering plane and counter steering plane are at an angle to one another.

A first aspect of the invention provides a system for controlling counter steer in a vehicle comprising one or more wheels, the system comprising a steering controller that is moveable in a steering plane to actuate steering of at least one of the one or more wheels, and moveable in a counter steering plane that is at an angle to the steering plane to actuate counter steering of at least one of the one or more wheels.

In this way, one steering controller (e.g. handlebars or a steering wheel) can be used in two different ways to control both steering and counter steering. As discussed above, counter steering is necessary to provide adequate control of tilting vehicles through a bend or to avoid an obstacle or regain control in an emergency. This is because counter steering of one or more wheels away from a direction of travel through a bend causes the vehicle to lean towards the direction of travel as a result of gyroscopic precession effects. However, counter steering via the known means of simply operating a steering controller by steering in a direction away from a desired direction of travel is not intuitive, and requires extensive experience. In contrast, the present invention provides a more intuitive means of providing counter steer, via a distinct movement of the steering controller in a plane that is different to the steering plane.

Steering in this context means movement/pivoting of at least one of the one or more wheels in the direction of travel around a bend approached by the vehicle, i.e. towards the inside of the bend. Counter steering means movement/pivoting of at least one of the one or more wheels away from the direction of travel, i.e. towards the outside of the bend. Thus, the steering controller is movable in the steering plane to cause at least one of the one or more wheels to steer in a direction of travel through a bend, and the steering controller is moveable in the counter steering plane to cause at least one of the one or more wheels to steer away from the direction of travel. Similarly, the system may be arranged such that wherein, in use, when the vehicle approaches a bend in a road, movement of the steering controller in the steering plane causes steering of at least one of the one or more wheels in a direction of travel through the bend, and movement of the steering controller in the counter steering plane causes counter steering of at least one of the one or more wheels away from the direction of travel.

In some embodiments movement of the steering controller in the counter steering plane and steering plane actuates counter steering and steering, respectively, of the same one or more wheels of the vehicle. In other embodiments movement in the counter steering plane actuates counter steering of at least one of the one or more wheels that are different to the at least one of the one or more wheels that are actuated in steering by movement of the steering controller in the steering plane. For example, movement of the steering controller in the steering plane may actuate a first steerable axle carrying one or more wheels, and movement in the counter steering plane may actuate a second steerable axle carrying one or more other wheels.

As a further example, movement of the steering controller in the steering plane preferably actuates pivoting of the at least one of the one or more wheels about a steering axis, and movement of the steering controller in the counter-steering plane preferably actuates counter- pivoting of the at least one of the one or more wheels about the steering axis.

In preferred embodiments the steering controller is movable in the counter steering plane to actuate temporary counter steering of the at least one of the one or more wheels. Thus, a momentary counter steering input can be provided to the wheel(s) to initiate lean of the vehicle towards an inside of a bend as a result of gyroscopic precession forces. Once the vehicle is leaning the counter steering input becomes unnecessary, and potentially harmful, so is discontinued. That is, the counter steering action does not continue throughout travel of the vehicle through a bend.

The steering controller is preferably biased towards a neutral configuration in which the steering controller does not actuate counter steering of the at least one of the one or more wheels. In the neutral configuration the steering controller is movable only in the steering plane to provide steering of the wheel(s). In this way, the rider/driver is automatically encouraged to provide only a temporary counter steering input to the wheel(s). Optionally, the system comprises a biasing member arranged to bias the steering controller towards the neutral configuration. The biasing member may, for example, comprise a mechanical component such as a spring or other resilient member.

The steering controller is preferably simultaneously moveable in the steering plane and the counter steering plane. In this way, counter steer can be applied at the same time as conventional steer through a bend.

In some embodiments the steering plane is generally perpendicular to the counter steering plane. In this way, steering may be effected by a generally forward-rearward movement by the rider/driver, and counter steering by a left-right movement, or vice versa. In some embodiments the steering controller comprises a right hand portion and a left hand portion, and the right hand portion is moveable in the counter steering plane to cause the at least one of the one or more wheels to counter steer to the left, and the left hand portion is moveable in the counter steering plane to cause the at least one of the one or more wheels to counter steer to the right. Thus, the rider/driver can provide the counter steering command with the hand that is towards the inside of a bend; this arrangement is particularly intuitive.

In preferred embodiments the right hand portion of the steering controller is moveable in the counter steering plane with a component directed away from an operator of the vehicle to cause the at least one of the one or more wheels to counter steer to the left, and the left hand portion of the steering controller is moveable in the counter steering plane with a component directed away from an operator of the vehicle to cause the at least one of the one or more wheels to counter steer to the right. For example, the rider/driver may push the right hand or left hand portion of the steering controller away from him or herself. For embodiments where the steering plane is closer to horizontal than vertical (e.g. where the steering controller comprises handlebars of e.g. a motorbike or trike) the movement may have a downwards component, since this is likely to be intuitive for the rider. For embodiments where the steering plane is closer to vertical than horizontal (e.g. where the steering controller comprises a steering wheel of e.g. a car or other enclosed vehicle) the movement may have a forwards component, since this is likely to be intuitive for the rider/driver.

As an example, right-wise (e.g. clockwise) movement of the steering controller in the counter steering plane relative to the rider/driver may provide left-wise (e.g. anti-clockwise) counter steering of the at least one of the one or more wheels, and left-wise (e.g. anti-clockwise) movement of the steering controller in the counter steering plane relative to the rider/driver may provide right-wise (e.g. clockwise) counter steering of the at least one of the one or more wheels.

In some embodiments movement of the steering controller in the counter steering plane comprises rotation of the steering controller about a counter steering axis. In other embodiments movement of the steering controller in the counter steering plane comprises translation or rotation of a portion of the steering controller relative to a neutral position of the counter steering plane. In preferred embodiments a degree of counter steering of the one or more wheels is generally proportional to a degree of movement of the steering controller away from a neutral configuration in the counter steering plane. The neutral configuration is a position of the steering controller in which the steering controller does not actuate counter steering of the at least one of the one or more wheels. In the neutral configuration the steering controller is movable only in the steering plane to thereby provide steering of the wheel(s); of course, movement of the steering controller in the steering plane may also provide counter steering in the conventional way.

The system preferably includes a steering linkage connected to the steering controller and configured to be connected to the one or more wheels of the vehicle, wherein the steering linkage is arranged to control the steering direction of the one or more wheels in a steering mode in which the one or more wheels are configured to travel in a direction of travel through a bend in response to movement of the steering controller in the steering plane, and in a counter steering mode in which the one or more wheels are configured to travel away from the direction of travel in response to movement of the steering controller in the counter steering plane. Thus, a single steering linkage can be used to provide both steering and counter steering.

In some embodiments movement of the steering controller in the counter steering plane is arranged to cause counter steering of the one or more wheels until the steering controller is returned to a neutral configuration of the counter steering plane. Thus, the operator must return the steering controller to the neutral configuration, either by purposeful action or by the result of a component or mechanism acting to urge the steering controller towards the neutral configuration.

In alternative embodiments movement of the steering controller in the counter steering plane is arranged to cause counter steering for a fixed period of time. In this way, the operator does not have to concern themselves with determining how long counter steering should be applied for, making the system more intuitive and enabling its use by less experienced riders/drivers.

Preferably, said fixed period of time is independent of a period of time for which the steering controller is moved away from a neutral position of the counter steering plane. Thus, the reaction times and experience of the rider/driver are even less of a factor in control of counter steer. The fixed period of time is preferably 2 seconds or less, optionally 1 second or less. Thus, counter steer is only momentary.

Some electronically signalled embodiments may comprise a load cell configured to receive an input force from the steering controller when the steering controller is moved in the counter steering plane and to generate an output signal based on the input force for actuating counter steering of the at least one of the one or more wheels. In this way, counter steering can be actuated by electronic means, based on the generated output signal. Preferably a property, such as an amplitude, of the output signal controls a degree of counter steer of the at least one of the one or more wheels.

In some embodiments the steering controller comprises handlebars or a steering wheel, for example.

In some mechanical embodiments a gearing mechanism may be provided. The gearing mechanism may include a first gear connected to the steering controller, and a second gear that is meshed with the first gear and connected to a steering linkage that is connectable to the at least one of the one or more wheels to control a steering direction thereof, wherein the steering controller is moveable in the counter steering plane to cause relative movement between the first gear and the second gear. In this way, movement of the steering controller in the steering plane results in corresponding movement of the entire gearing mechanism and consequential steering movement of the steering linkage. During such a steering operation there is no relative movement between the meshed first and second gears. Movement of the steering controller in the counter steering plane, however, results in movement of the first gear and corresponding relative movement of the second gear, leading to counter steering movement of the steering linkage.

The first and second gears of the gearing mechanism may be bevel gears. Thus, the rotational axes of the first and second gears may be substantially perpendicular to one another.

Alternatively, the first gear may comprise a toothed rack and the second gear may comprise a pinion gear. Thus, movement of the steering controller in the counter steering plane may result in translational movement of the toothed rack, resulting in corresponding rotational movement of the meshed pinion gear and resultant counter steering movement of the steering linkage. Some electronically signalled embodiments may comprise an electronic control system arranged to control a steering direction of at least one of the one or more wheels based on an electronic signal generated by movement of the steering controller in the steering plane and/or counter steering plane. The electronic signal may comprise the output signal from a load cell, as described above.

The system may further comprise a stabilising mechanism arranged to cause a change in an angle of tilt of the vehicle in response to movement of the steering controller in the counter steering plane. In this way, the counter steering control described above can be enhanced and/or supplemented.

The steering controller is preferably moveable in the counter steering plane to first actuate counter steering of the at least one of the one or more wheels and subsequently activate the stabilising mechanism to cause a change in an angle of tilt of the vehicle. As the vehicle gains forward speed it demonstrates greater reluctance to change its tilt orientation owing to the reluctance of the spinning wheels to lean either way. By first actuating counter steer in the at least one of the one or more wheels the reluctance of the vehicle to lean will be reduced, and the stabilising counter lean mechanism should be more effective.

In some embodiments the stabilising mechanism comprises a moveable portion of a body of the vehicle that is movable relative to a remainder of the vehicle body in a direction of counter steer of the one or more wheels. For example, the moveable portion may comprise a seat, battery, oil tank or roll cage of the vehicle, or any other component(s) with sufficient mass above the centre of mass of the vehicle.

In other embodiments the stabilising mechanism comprises a tilt control device arranged to change a configuration of a portion of the vehicle such that the vehicle tilts, or has a tendency to tilt, in the manner desired by the rider/driver.

Alternatively, or in addition, the stabilising mechanism may comprise a tilt control device arranged to control tilt of a tilting axle of the vehicle relative to a surface on which the vehicle is travelling and/or a body of the vehicle, wherein the tilting axle carries one or more wheels of the vehicle. The tilt control device may be controlled by a remote device monitoring a position of the steering controller in the counter-steering plane. In some embodiments the tilt control device is arranged to resist a change in an angle of tilt of the vehicle in a direction opposed to a desired direction of tilt. Thus, the tilt control device may prevent vehicle tilt in an unwanted direction. The tilt control device may be operable in a first configuration in which it resists a change in an angle of tilt of the vehicle in a first direction, and a second configuration in which it resists a change in an angle of tilt of the vehicle in a second direction opposite to the first direction. The tilt control device may be switchable between the first and second configurations in response to a position of the steering controller in the counter-steering plane. For example, movement of the steering controller in a first direction in the counter-steering plane may result in operation in the first configuration, and movement of the steering controller in a second direction opposite to the first direction in the counter-steering plane may result in operation in the second configuration.

In resisting a change in an angle of tilt the tilt control device may oppose a tilting force applied to the axle assembly, e.g. as a result of movement of the axle assembly in response to travel over rough ground. For example, the resisting device may dampen, absorb or otherwise negate a force to the axle assembly.

Alternatively, or in addition, the tilt control device may comprise an actuator arranged to actuate a change in an angle of tilt of the vehicle in a desired direction of tilt. Thus, the tilt control device may be arranged to provide a desired vehicle tilt. The tilt control device may be operable in a first configuration in which it enables a change in an angle of tilt of the vehicle in a first direction only, and a second configuration in which it enables a change in an angle of tilt of the vehicle in a second direction opposite to the first direction only. The tilt control device may be switchable between the first and second configurations in response to a position of the steering controller in the counter-steering plane. For example, movement of the steering controller in a first direction in the counter-steering plane may result in operation in the first configuration, and movement of the steering controller in a second direction opposite to the first direction in the counter-steering plane may result in operation in the second configuration.

The tilt control device preferably receives no power supply from the vehicle. All power inputs to the tilt control device preferably result from movement of a portion of the vehicle, e.g. movement of the steering controller, and/or movement of an axle assembly relative to a vehicle chassis.

The tilt control device may comprise a hydraulic cylinder connected between a tilting axle of the vehicle and a chassis of the vehicle, and a valve arranged to control a direction of flow of hydraulic fluid within the hydraulic cylinder. For example the tilt control device may comprise a hydraulic cylinder and a valve permitting movement of the hydraulic cylinder (i.e. movement of a piston within a cylinder barrel of the hydraulic cylinder) in one direction only.

In such embodiments the system may further comprise a force acting device arranged to transmit a force to a piston or cylinder barrel of the hydraulic cylinder to cause relative movement therebetween, the force acting device being operable in response to movement of the steering controller. In this way, the‘overrun’ of hydraulic fluid in the cylinder may serve to promote vehicle tilt in the desired direction.

The tilt control device is preferably arranged to maintain a desired vehicle tilt after the steering controller has returned to the neutral position. That is, momentary movement of the steering controller in the counter steering plane may result in continued vehicle tilt in a desired direction.

The tilt control device preferably comprises a force acting device arranged to promote (i.e. magnify, accelerate or otherwise increase) the change in angle of tilt, optionally by increasing a rate of change of the angle of tilt. This arrangement enables rapid change in tilt angle and thus enables momentary (i.e. temporary) rotation of the steering controller in the counter steering plane to simultaneously activate the stabilising system and trigger counter steer.

In preferred embodiments the tilt control device is operable only at or below a threshold speed. Such a device may only have perceived benefits at such low speeds. The threshold speed may be, for example, within the range of 15 to 20 miles per hour (mph).

The tilt control device is preferably arranged to provide a gradually decreasing resistance to change in angle of tilt and/or gradually decreasing actuation of a change in angle of tilt with increase in speed of the vehicle. In this way, it is possible to control the degree to which the tilt control device can influence vehicle tilt as vehicle speed increases. The tilt control device may provide no resistance to change in angle of tilt and/or actuation of change in angle of tilt above a relatively high threshold speed. The speed of the vehicle at which there is no longer any degree of resistance to change in the angle of tilt may be moderately high, for example such as 30 mph, or 40 mph, or 50 mph, or even 60 mph. Alternatively, the system may be arranged such that when the vehicle is travelling at its top speed there is still some degree of resistance to the angle of tilt (i.e. wherein the top speed of the vehicle defines the point at which there is a minimum degree of resistance to the angle of tilt). In some embodiments, the system is arranged such that movement of the steering controller in the counter steering plane away from the neutral configuration is arranged to actuate a change in an angle of tilt of a vehicle incorporating the system, and wherein movement of the steering controller in the counter steering plane beyond a predetermined boundary is arranged to promote the change in an angle of tilt of the vehicle.

In this way the rider/driver of the vehicle has influence over the tilt of the vehicle by (relatively small) displacements of the steering controller up to and within the pre-determined boundary, until the steering controller is rotated, in the counter steering plane, beyond the pre-determined boundary (i.e. by a large displacement of the steering controller). Once the steering controller is displaced beyond the pre-determined boundary, a remote control system activates a force acting device arranged to promote (i.e. magnify, accelerate or otherwise increase) the change in angle of tilt, optionally by increasing a rate of change of the angle of tilt. This arrangement enables momentary (i.e. temporary) rotation of the steering controller in the counter steering plane to simultaneously activate the stabilising system and trigger counter steer. Advantageously, the system may be set up such that the device continues to promote the change in angle of tilt until the steering controller is returned to the neutral position (i.e. until the steering controller is no longer displaced).

For example, the system may be arranged such that rotation of the steering controller in the counter steering plane either right-wise (i.e. clockwise with respect to the rider/driver) or left- wise (i.e. anticlockwise with respect to the rider/driver) up to and including a predetermined angle from the neutral configuration actuates a change in an angle of tilt of a vehicle incorporating the system, and such that movement of the steering controller in the counter steering plane by an angle greater than the predetermined angle is arranged to promote the change in an angle of tilt of the vehicle.

In the above example, the pre-determined angle of rotation of the steering controller may be an angle of 30° or less right-wise (i.e. clockwise with respect to the rider/driver) or left-wise (i.e. anticlockwise with respect to the rider/driver) from the neutral configuration. In some embodiments, the pre-determined boundary may be an angle of 1 °, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, or 20°from the neutral configuration or any angle within the range of 1 ° to 30°.

The system may comprise an actuator arranged to actuate the change in angle of tilt. The system may further comprise a resisting device operable to resist the change in angle of tilt. Thus, such a resisting device may be any device capable of being arranged to resist the change in an angle of tilt of the vehicle. The device may, for example, comprise a hydraulic, pneumatic or electric control system. Advantageously, the device may comprise a hydraulic control system.

Movement of the steering controller in the counter steering plane beyond the predetermined boundary may be arranged to resist the change in an angle of tilt of the vehicle by applying a resistive force to oppose the change in the angle of tilt.

For example, the system may be arranged such that when the driver/rider rotates the steering controller right-wise (i.e. clockwise) the axle assembly tilts towards the right, and such that when the driver/rider rotates the steering controller right-wise (i.e. clockwise) beyond the predetermined threshold, rotation of the steering controller right-wise (i.e. clockwise) also applies a left-wise resistive force to oppose the change in angle of tilt to the right.

In some embodiments, movement of the steering controller beyond the predetermined boundary is arranged to not resist the change in the angle of tilt when the vehicle has a speed equal to or greater than a threshold speed. Such a system is particularly advantageous for vehicles that are likely to cover rough terrain or occasionally encounter large bumps at high speed. In this system, counter steer is able to function at all speeds, but is only effective at the predetermined speed and above; and the actuator does not actuate the stabilising system above the predetermined speed. The system may suitably be arranged such that the threshold speed of the vehicle is about 10 mph, or about 15 mph, or about 20 mph, or even about 25 mph.

In some embodiments, a degree of resistance to the angle of tilt may decrease gradually with increasing speed of the vehicle. The speed of the vehicle at which there is no longer any degree of resistance to the angle of tilt may be moderately high, for example such as 30 mph, or 40 mph, or 50 mph, or even 60 mph. Alternatively, the system may be arranged such that when the vehicle is travelling at its top speed there is still some degree of resistance to the angle of tilt (i.e. wherein the top speed of the vehicle defines the point at which there is a minimum degree of resistance to the angle of tilt).

In some embodiments, movement of the steering controller in the counter steering plane does not actuate counter steering when the vehicle has a speed equal to or less than a threshold speed. This is particularly advantageous for tilting vehicles negotiating very rough terrain. The driver/rider is free at low vehicle speed to maintain stability by vigorously rotating the handlebars without causing disruptive/inappropriate turning of the steerable wheel(s).

The threshold speed for counter steering may be about 10 mph, or about 15 mph, or about 20 mph, or even about 25 mph. The threshold speed for counter steering may be the same as the threshold speed at which movement of the steering controller beyond the predetermined boundary is arranged to not resist the change in the angle of tilt. Alternatively, the threshold speed for counter steering may be different to the threshold speed at which movement of the steering controller beyond the predetermined boundary is arranged to not resist the change in the angle of tilt.

In an alternative embodiment, the degree of counter steering actuated by a given movement of the steering controller in the counter steering plane may increase gradually with increasing speed of the vehicle.

In the above tilting vehicle embodiments the one or more wheels of the vehicle carried by the tilting axle of the vehicle are preferably different to the one or more wheels that are actuatable to provide steering (and, in some arrangements, counter steering) in response to movement of the steering controller in the steering plane (or counter steering plane in the previously mentioned arrangements). In this way, both the steerable wheel(s) and non-steerable wheel(s) can be controlled to contribute to control of lean through a bend.

A second aspect of the invention provides a vehicle comprising a system as defined in relation to the first aspect above, and one or more wheels, wherein the steering controller is moveable in the steering plane to actuate steering of the at least one of the one or more wheels, and moveable in the counter steering plane to actuate counter steering of the at least one of the one or more wheels.

The vehicle preferably has at least two wheels, at least one of said wheels being actuatable by the steering controller to provide steering and at least one of said wheels being actuatable by the steering controller to provide counter steering. In some embodiments the same wheel(s) are actuatable to provide both steering and counter steering. In other embodiments different wheels are actuatable to provide steering and counter steering.

In some embodiments the vehicle has at least three wheels, at least one of said wheels being actuatable by the steering controller to provide steering and at least one of said wheels being actuatable by the steering controller to provide counter steering. In some embodiments the same wheel(s) are actuatable to provide both steering and counter steering. In other embodiments different wheels are actuatable to provide steering and counter steering.

The vehicle preferably comprises a power source arranged to provide motive force to one or more wheels of the vehicle. Alternatively, the vehicle may be powered by rider input via pedals. The power source preferably does not provide power, or provides only minimal power, to any tilt control device incorporated into the vehicle. For example, the power source may provide minimal power required to control electrically actuated hydraulic valves.

The vehicle preferably comprises a tilting vehicle able to lean relative to a road surface.

The vehicle may comprise, for example, a motorcycle, a trike, a car, a quad bike, a scooter, a pedal-powered vehicle, or an electric bicycle. In some embodiments, the vehicle may comprise a three or four wheeled non-powered or pedal powered vehicle, for example a four wheeled tilting downhill mountain bike.

Tilting vehicles incorporating the invention may have many beneficial characteristics offered by both motorcycles and cars, including weather protection, roll-over protection, relatively high eye-level, and a safety harness for the rider/driver.

The vehicle may have a single seat, or may be a multi-seat vehicle in which the seats are arranged one behind the other in a tandem layout.

As an example, such a vehicle could form the basis for a lightweight monorail system whereby the vehicles are hooked onto the rail for travel over longer distances, and dropped off within busy urban areas for independent travel. The vehicle and the rail system may be electrically powered.

Alternatively, the invention could form the basis for a new racing formula where its distinctive features offer potential for a more entertaining event, e.g. more spectacular recoveries from vehicles almost skidding out of control.

In three or four wheeled vehicles incorporating the invention it is envisaged that at least one wheel axle will be able to tilt relative to a surface on which the vehicle is travelling. For example, the at least one axle may be able to tilt relative to at least a portion of the vehicle. In some embodiments, one or more of such axles may be able to tilt relative to the main chassis, frame and/or body of the vehicle.

The tilting axle may carry the steerable wheel(s) of the vehicle or be a non-steerable axle. For example, the front wheel(s) of the vehicle may be mounted on a steerable axle and the rear wheel(s) may be mounted on a tiltable axle. Preferably, at least one wheel axle will be non tilting (i.e. remain perpendicular to the main chassis). This would allow the rider/driver to control counter steering using the wheel(s) of the non-tiling axle, and to control lean of the vehicle by means of an actuator system associated with the wheel(s) of the tilting axle.

A three wheeled vehicle may have two front wheels and one rear wheel, or it may have one front wheel and two rear wheels. In an embodiment, when the vehicle is a three wheeled vehicle, the whole body and all three wheels may tilt relative to a surface on which the vehicle is travelling. In another embodiment, when the vehicle is a three wheeled vehicle, most of the vehicle including the front wheel(s) may tilt relative to the surface on which the vehicle is travelling, whilst the axle(s) of the rear wheel(s) may remain substantially perpendicular to the surface on which the vehicle is travelling. In yet another embodiment, when the vehicle is a three wheeled vehicle, most of the vehicle including the rear wheel(s) may tilt relative to the surface on which the vehicle is travelling, whilst the axle(s) of the front wheel(s) may remain substantially perpendicular to the surface on which the vehicle is travelling.

A four wheeled vehicle typically has two front wheels and two rear wheels. However, it may have three front wheels and one rear wheel, or it may have one front wheel and three rear wheels. In an embodiment, when the vehicle is a four wheeled vehicle, the whole body and all four wheels may tilt relative to a surface on which the vehicle is travelling. In another embodiment, when the vehicle is a four wheeled vehicle, most of the vehicle including the front wheel(s) may tilt relative to the surface on which the vehicle is travelling, whilst the axle(s) of the rear wheel(s) may remain substantially perpendicular to the surface on which the vehicle is travelling. In yet another embodiment, when the vehicle is a four wheeled vehicle, most of the vehicle including the rear wheel(s) may tilt relative to the surface on which the vehicle is travelling, whilst the axle(s) of the front wheel(s) may remain substantially perpendicular to the surface on which the vehicle is travelling.

A third aspect of the invention provides a method of operating the system of the first aspect to control counter steer in a vehicle comprising one or more wheels, the method including the steps of: moving the steering controller in the counter steering plane to cause counter steering of the at least one of the one or more wheels away from a direction of travel of the vehicle through a bend. The vehicle may comprise a vehicle according to the second aspect.

Throughout the description and claims of this specification, the words“comprise” and“contain” and variations of the words, for example“comprising” and“comprises”, mean“including but not limited to”, and do not exclude other components, integers or steps. Moreover the singular encompasses the plural unless the context otherwise requires: in particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

Preferred features of each aspect of the invention may be as described in connection with any of the other aspects. Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. In particular, any features described in relation to the first aspect may be applied to either the second or third aspects.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1A is a front view of a system for controlling counter steer in a motorbike;

Figure 1 B is a plan view of the system of Figure 1 A;

Figure 1 C is a sectional side view of the system of Figures 1A;

Figure 2 is a sectional view of an alternative embodiment of the bevel gear housing of the system of Figure 1A;

Figure 3A is a view on a steering controller in a system for controlling counter steer in a vehicle utilising two bevel gear units;

Figure 3B is a plan view of the system of Figure 3A;

Figure 3C is a sectional side view of the system of Figure 3A; Figure 4A is a view on a steering controller in a system for controlling counter steer in a vehicle utilising a split steering component;

Figure 4B is a plan view of the system of Figure 4A;

Figure 4C is a sectional side view of the system of Figure 4A;

Figure 5A is a view on a steering controller in a system for controlling counter steer in a vehicle utilising signals from a load cell;

Figure 5B is a side view of the system of Figure 5A;

Figure 5C is a plan view of the system of Figure 5A;

Figure 6A is a view on a steering controller in a simple mechanical system for controlling counter steer in a vehicle;

Figure 6B is a plan view of the system of Figure 6A;

Figure 6C is a sectional side view of the system of Figure 6A;

Figure 7 is a rear view of a stabilising system for a motorbike that mimics a rider counter leaning;

Figure 8 is a partially symbolic view of a front or rear axle assembly comprising a stabilising system;

Figure 9 is a rear view of a tilting axle of a three wheeled vehicle incorporating a stabilising system;

Figure 10 is a front view of part of the vehicle of Figure 9;

Figure 11 is a rear perspective view of a prior art three wheeled vehicle; and

Figure 12 is a rear view of the three wheeled vehicle of Figure 1 1 , incorporating a system for controlling counter steer according to an embodiment of the invention.

DETAILED DESCRIPTION

Referring to Figures 1A and 1 B, a system 100 for controlling counter steer in a motorbike comprises handlebars 105, bevel gear housing 1 10, and headset 1 15. Within the bevel gear housing 110, the handlebars 105 are coupled to headset 1 15 by a bevel gear connection, which is described in more detail below. Headset 115 passes through a head tube 120 and is attached to a front fork 125. Headset 115 is able to freely rotate within head tube 120. Head tube 120 forms part of the frame 140 of the motorbike (as shown in Figure 1 B), which supports a seat (not shown) for a rider of the motorbike. Front fork 125 connects to axle 130, which carries a front wheel 135 between the arms of the front fork 125. Axle 130 passes through the front wheel 135 such that front wheel 135 can rotate freely about the axle 130.

In Figure 1A, a person riding the motorbike, i.e. the rider (not shown) sits behind the handlebars 105 and faces the handlebars 105 in the plane of Figure 1A. The handlebars have a left hand side 107 and a right hand side 109 with respect to the rider. In order to steer the motorbike, the rider rotates (indicated by arrow 165) the handlebars 105 from their neutral position as (as shown in Figures 1A and 1 B) either left-wise (anti-clockwise relative to the rider) or right-wise (clockwise relative to the rider) about the steering axis 160 in the steering plane (i.e. in the plane of Figure 1 B).

Right-wise rotation 165 about the steering axis 160 can be achieved by the rider pushing the left hand side 107 of the handlebars 105 away from them and/or by pulling the right hand side 109 of the handlebars 105 back towards them. Conversely, left-wise rotation 165 about the steering axis 160 can be achieved by the rider pushing the right hand side 109 of the handlebars 105 away from them and/or by pulling the left hand side 107 of the handlebars 105 back towards them.

Rotation 165 of the handlebars 105 about the steering axis 160 causes the whole bevel gear housing 110 to rotate about the steering axis 165, which results in rotation 165 of the headset 115 about the steering axis, and thus causes front fork 125 and front wheel 135 to pivot. As a result, the motorbike changes direction and steers to the left or to the right. The motorbike will continue steering to the left or to the right until the rider moves the handlebars 105 back to the starting position, i.e. back into the plane of Figure 1A. Thus, steering of the motorbike is achieved by a conventional steering operation.

Figure 1 C shows a cross-sectional view of the bevel gear housing 110 of Figure 1A. A handlebar shaft 112 (shown in Figure 1 B) is rigidly connected to a midpoint of the handlebars 105 and extends rearwardly therefrom. The bevel gear housing 110 comprises a first opening 1 18, through which handlebar shaft 112 passes. The first opening 118 optionally includes a bush or bearing (not shown) to support the handlebar shaft 1 12 and permit rotation therein. Handlebar shaft 1 12 is rigidly joined to a first bevel gear 113 which meshes with a second bevel gear 114 that is substantially perpendicular to the first bevel gear 113 (i.e. rotates about an axis that is substantially perpendicular to the rotational axis of the first bevel gear 113). The second bevel gear 1 14 is rigidly joined to headset 115, headset 1 15 extending substantially perpendicular to the handlebar shaft 112. The bevel gear housing 110 is provided with a second opening 1 19 through which headset 115 passes. The second opening 1 19 optionally includes a bush or bearing (not shown) to support the headset 115 and permit rotation therein.

When riding the motorbike, the rider sits behind bevel gear housing 1 10, with the handlebars 105 being in front of the bevel gear housing 110, i.e. the bevel gear housing 110 is positioned between the rider and the handlebars 105. As discussed above, in order to steer the motorbike, the rider rotates 165 the handlebars 105 from their neutral position as (as shown in Figures 1A and 1 B) about the steering axis 160 in the steering plane (i.e. in the plane of Figure 1 B). Rotation 165 of the handlebars 105 about the steering axis 160 causes the whole bevel gear housing 1 10 to rotate about the steering axis 160. The teeth of bevel gears 113 and 114 are meshed, and thus rotation 165 of handlebar axle 112 about the steering axis 160 causes the whole bevel gear housing 110 and headset 115 to rotate 165 about the steering axis 160, thereby causing the front fork 125 and front wheel 135 to pivot. As a result, the motorbike changes direction and steers to the left or to the right.

In addition to steering the motorbike as described above, the rider can also press downwards (or pull upwards) on either the right hand side 109 or left hand side 107 of the handlebars 105 to effect counter steering of the motorbike. Pressing down on either the right hand side 109 or left hand side 107 of the handlebars 105 results in rotation 175 of the handlebars 105 about a counter steering axis 170 in the counter steering plane (i.e. in the plane of Figure 1A). This causes handlebar shaft 1 12 to rotate 175 about the counter-steering axis 170, thereby resulting in rotation 175 of the first bevel gear 113 about the counter steering axis 170. Rotation 175 of the first bevel gear 113 in turn results in rotation 165 of the second bevel gear 1 14 about the steering axis 160, causing the headset 1 15 to rotate 165 about the steering axis 160, thus causing the front fork 125 and front wheel 135 to pivot.

This arrangement provides that pressing down on right hand side 109 of the handlebars 105 results in left-wise rotation 165 of the headset 115 about the steering axis 160 such that the front fork 125 and front wheel 135 pivot to the left. With this set-up, as the rider steers the motorbike into a right-hand turn (optionally by right-wise rotation 160 of the handlebars 105 about the steering axis 165 to pivot the wheel 135 to the right, but alternatively or in addition by leaning the motorbike to the right), momentarily pressing down the right hand side 109 of the handlebars 105 results in left-wise (clockwise relative to the rider) rotation 175 of the handlebars 105 about the counter steering axis 170 which causes the front wheel 135 to momentarily pivot to the left, thereby resulting in counter steering of the motorbike.

Similarly, pressing down on the left hand side 107 of the handlebars 105 results in right-wise rotation of the headset 115 about the steering axis 160 such that the front fork 125 and front wheel 135 pivot to the right. In this way, as the rider steers the motorbike into a left-hand turn, momentarily pressing down on the left hand side 107 of the handlebars 105 results in left-wise (anti-clockwise relative to the rider) rotation 175 of the handlebars 105 about the counter steering axis 170 which causes the front wheel 135 to momentarily pivot to the right, thereby resulting in counter steering of the motorbike.

As mentioned previously, counter steering left when steering right into a right-hand turn (and vice versa) can be counter-intuitive to less experienced riders. Therefore, by providing a system 100 wherein pressing down on right hand side 109 of the handlebars 105 causes counter steer of the motorbike to the left, and vice versa, the system 100 presents the rider with an instinctive means of control of the motorbike. Moreover, momentarily counter steering the motorbike left, when steering right into a right-hand turn, causes the motorbike to lean towards to the right-hand turn, thereby tilting the motorbike and giving the rider better control of the motorbike in the turn.

A skilled rider, such as a racing motorcyclist, may choose not to hold the handlebars in the plane of Figure 1 A. Furthermore, as a way of adjusting to the terrain and/or to suit their riding style, the rider may choose to apply slightly more, or less, counter steer by simultaneously turning the handlebars marginally clockwise or anticlockwise about the steering axis 160.

Figure 2 shows a cross-sectional view of part of an alternative system 101 for controlling counter steer in a motorbike that is substantially identical to system 100 illustrated in Figures 1A, 1 B and 1 C, but with a different location and internal arrangement of the bevel gear housing 1 10. In this arrangement, the bevel gear housing 110 is positioned in front of (relative to the rider) the handlebars 105 i.e. handlebars 105 are positioned between the rider and the bevel gear housing 1 10. Thus, the handlebar shaft 1 12 extends through openings in opposing walls of the housing 110, those openings optionally including bushes or bearings to support the handlebar shaft 1 12 and permit rotation thereof. In systems 100 and 101 described above, headset 1 15 can alternatively be linked to an electronic steering by wire system, instead of having a direct mechanical connection to the front wheel 135. In addition to controlling the steering and counter-steering movements of the front wheel 135, the electronic steering system could also be adapted to control the movements of other wheels.

Figures 3A to 3C show a system 200 for controlling counter steer in a vehicle with a steerable front axle (not shown). System 200 is particularly suited to motor-powered vehicles. However, system 200 could also be used in a pedal-powered vehicle, for example a four-wheeled tilting mountain bike. A steering linkage 250 interconnects with the steerable axle to control the direction of travel of wheels mounted on that axle. The system 200 comprises two interconnecting bevel gear units, including an upper bevel gear housing 210 and a lower bevel gear housing 220 interconnected by headset 215. Within the upper bevel gear housing 210, the steering controller 205 is coupled to headset 215 by a bevel gear connection similar to that described above for system 100 (or system 101). The upper bevel gear housing 210 swivels with the steering controller 205. The lower gear housing 220 is fixed.

A steering controller 205 is attached to upper bevel gear housing 210 by steering controller shaft 212. Steering controller 205 has a left hand side 207 and right hand side 209 with respect to the person driving the motor-powered vehicle, i.e. the rider/driver. The steering controller 205 is of a drop-down handlebar style and has a series of undulated grips 206 on both the left and right hand sides 207, 209 to enable to the rider/driver to more comfortably and securely grasp the steering controller 205.

Also connected to the upper bevel gear housing 210 is headset 215. The upper bevel gear housing 210 comprises (see Figure 3C) a first opening 218, through which steering controller shaft 212 passes. The first opening 218 optionally includes a bush or bearing to support the steering controller shaft 212 while permitting rotation thereof. Steering controller shaft 212 is rigidly attached to a first bevel gear 213 which meshes with a second bevel gear 214 rigidly attached to headset 215. The upper bevel gear housing 210 is provided with a second opening 219 through which headset 215 passes, optionally via a bush or bearing that supports the headset 215 while permitting rotation thereof.

The lower bevel gear housing 220 contains (see Figure 3C) a third bevel gear 216 rigidly connected to the second bevel gear 214 of the upper bevel gear housing 210 via the headset 215. The third bevel gear 216 meshes with a fourth bevel gear 217 in the lower bevel gear housing 220, the fourth bevel gear 217 being rigidly connected to the steering linkage 250 to control rotation thereof.

Referring to Figure 3A the rider/driver sits in front of the steering controller 205 and faces towards the steering controller in the plane of Figure 3A. In order to steer the vehicle, the rider/driver rotates (as indicated by arrow 265) the steering controller 205 from its neutral position (as shown in Figures 3A to 3C) either clockwise (right-wise) or anticlockwise (left- wise) about the steering axis 260 in the steering plane (i.e. in the plane of Figure 3B).

Clockwise rotation 265 about the steering axis 260 can be achieved by the rider/driver pushing the left hand side 207 of the steering controller 205 forwards and/or by pulling the right hand side 209 of the steering controller 205 rearwards (relative to the plane of Figure 3A). Conversely, anticlockwise rotation 265 about the steering axis 260 can be achieved by the rider/driver pushing the right hand side 209 of the steering controller 205 forwards and/or by pulling the left hand side 207 of the steering controller 205 rearwards.

Left-wise or right-wise rotation 265 of the steering controller 205 about the steering axis 260 causes the whole upper bevel gear housing 210 to rotate 265 about the steering axis 260. The teeth of first and second bevel gears 213 and 214 are interlocked, and thus rotation 265 of the whole upper bevel gear housing 210 about the steering axis 260 causes the headset 215 to rotate. This in turn results in rotation of the third bevel gear 216 in the lower bevel gear housing 220. Rotation of the third bevel gear 216 in turn results in rotation of the fourth bevel gear 217, and consequently effects rotation of steering linkage 250.

Conveniently, the system 200 is arranged such that clockwise rotation 265 of the steering controller 205 about the steering axis 260 causes the one or more front (steerable) wheels of the vehicle to pivot to the right, resulting in steering of the vehicle to the right, and anticlockwise rotation 265 of the steering controller 205 about the steering axis 260 causes the one or more front (steerable) wheels of the vehicle to pivot to the left, resulting in steering of the vehicle to the left.

In addition to steering the vehicle as described above, the rider/driver can also rotate 275 the steering controller 205 from its neutral position (as shown in Figures 3A to 3C) about the counter steering axis 270 in the counter steering plane (i.e. in the plane of Figure 3A) to effect counter steering of the vehicle. The counter steering axis 270 is substantially perpendicular to the steering axis 260 in this embodiment, though in other embodiments the axes may be arranged at any angle relative to one another. Right-wise (clockwise) rotation 275 of the steering controller 205 about the counter steering axis 270 can be achieved by the rider/driver pushing the left hand side 207 of the steering controller 205 upwards and/or by pulling the right hand side 209 of the steering controller 205 downwards. Conversely, left-wise (anti clockwise) rotation 275 of the steering controller 205 about the counter steering axis 270 can be achieved by the rider/driver pushing the right hand side 209 of the steering controller 205 upwards and/or by pulling the left hand side 207 of the steering controller 205 downwards.

Rotation 275 of the steering controller 205 about the counter steering axis 270 causes the steering controller shaft 212 to rotate 275 about the counter steering axis 270, thereby resulting in rotation 275 of first bevel gear 313 about the counter steering axis 270. Rotation 275 of first bevel gear 213 in turn results in rotation of second bevel gear 214, causing rotation of headset 215, which in turn causes rotation of third bevel gear 216 in the steering axle lower bevel gear housing 220. Rotation of bevel gear 216 in turn results in rotation of fourth bevel gear 217, and consequently rotates steering linkage 250. Clockwise (right-wise) rotation of the steering controller 205 about the counter steering axis 270 results in anti-clockwise rotation of the steering linkage 250 (as viewed in the plane of Figure 3A), and vice versa. The steering linkage 250 may be linked to an electronic steering by wire system or by direct mechanical connection to one or more wheels of the motor-powered vehicle, optionally via a steerable axle.

The system 200 is thus arranged such that right-wise rotation 275 of the steering controller 205 about the counter steering axis 270 results in counter steering of the vehicle to the left and left-wise rotation 275 of the steering controller 205 about the counter steering axis 270 results in counter steering of the vehicle to the right, and vice versa. With this set-up, the rider/driver steers the vehicle into a right-hand turn (optionally by clockwise rotation 265 of the steering controller 205 about the steering axis 260), resulting in steering of the vehicle to the right, and can momentarily push the right hand side 209 of the steering controller 205 downwards (and/or push the left hand side 207 upwards) to cause the steerable vehicle wheel(s) to momentarily pivot to the left, thereby resulting in counter steering of the vehicle.

In an alternative embodiment, the system 200 may be arranged such that rotation of the steering controller 205 from its neutral position (as shown in Figures 3A to 3C) either clockwise (right-wise) or anticlockwise (left-wise) about counter steering axis 270 provides for steering of the vehicle, whilst rotation of the steering controller 205 from its neutral position (as shown in Figures 3A to 3C) either clockwise (right-wise) or anticlockwise (left-wise) about steering axis 260 in the plane of Figure 3B provides for counter steering of the vehicle. In other words, rotation of the steering controller 205 about the counter steering axis 270 may be used to effect steering of the vehicle, whilst rotation about the steering axis 260 effects counter steering of the vehicle. Such an arrangement of system 200 may be particularly suited to vehicles where the rider/driver is wearing a safety harness.

Figures 4A to 4C illustrate a system 300 for controlling counter steer in a vehicle with a steerable front axle (not shown). System 300 is particularly suited to motor-powered vehicles. However, system 300 could also be used in a pedal-powered vehicle, for example a four- wheeled tilting mountain bike. A steering linkage 350 interconnects with the steerable axle to control the direction of travel of wheels mounted on that axle. The system 300 incorporates a split steering component, and comprises a steering controller 305 divided into two separate parts: a left hand side 307 and a right hand side 309. The steering controller 305 is of a drop down handlebar style and has a series of undulated grips 306 on both the left and right hand sides 307, 309 to enable to the rider/driver to more comfortably and securely grasp the steering controller 305.

The system also comprises a rack and pinion housing 340. As can be seen from Figure 4B, the rack and pinion housing 340 encloses a pinion gear 342, a rack portion of the left hand side of handlebar 344, and a rack portion of the right hand side of handlebar 346. The rack portions 344 and 346 each have a row of teeth that engage (i.e. mesh) with a series of teeth on the pinion 342. The pinion gear 342 is rigidly connected to a first bevel gear 314 via a shaft so that rotation of the pinion gear 342 results in corresponding rotation of the first bevel gear 314. The first bevel gear 314 meshes with a second bevel gear 316 arranged substantially perpendicular to the first bevel gear, the second bevel gear 316 being rigidly connected to the steering linkage 350 so that rotation of the second bevel gear 316 results in corresponding rotation of the steering linkage 350. The steering linkage 350 is supported by a fixed bush, bearing or similar mounting 320 which permits rotation of the steering linkage 350 therein.

Referring to Figure 4A, the rider/driver sits in front of the steering controller 305 and faces towards the steering controller in the plane of Figure 4A. In order to steer the vehicle, the rider/driver rotates 365 the steering controller 305 either clockwise (right-wise) or anticlockwise (left-wise) about the steering axis 360.

Clockwise rotation 365 about the steering axis 360 can be achieved by the rider/driver pushing the left hand side 307 of the steering controller 305 upwards and/or by the pulling the right hand side 309 of the steering controller 305 downwards. Conversely, anticlockwise rotation 365 about the steering axis 360 can be achieved by the rider/driver pushing the right hand side 309 of the steering controller 305 upwards and/or by pulling the left hand side 307 of the steering controller 305 downwards.

Rotation 365 of the steering controller 305 about the steering axis 360 from its neutral position (as shown in Figures 4A to 4C) in the steering plane (i.e. in the plane of Figure 4A) causes the whole rack and pinion housing 340 to rotate about the steering axis 360. As can be seen from Figure 4C, within the rack and pinion housing 340, the teeth of first 314 and second 316 bevel gears are interlocked, and thus rotation 365 of the steering controller 305 about the steering axis 360 causes rotation 365 of the steering linkage 350 within the bush 320. Steering linkage 350 may be linked to an electronic steering by wire system or by direct mechanical connection to one or more wheels of the motor-powered vehicle.

As with the system 200 described above in relation to Figures 3A-C, system 300 is conveniently arranged such that clockwise rotation 365 of the steering controller 305 about the steering axis 360 causes the one or more front (steerable) wheels of the vehicle to pivot to the right, resulting in steering of the vehicle to the right, and anticlockwise rotation 365 of the steering controller 305 about the steering axis 360 causes the one or more front (steerable) wheels of the vehicle to pivot to the left, resulting in steering of the vehicle to the left, and vice versa.

In addition to steering the vehicle as described above, the rider/driver can also push or pull 380, 390 the left hand or right hand sides 307, 309, respectively, of the steering controller 305 to effect counter steering of the vehicle. Pushing or pulling 380, 390 the left hand or right hand sides 307, 309 respectively of the steering controller 305 results in linear movement of the rack 344 of the left hand side of handlebar or of the rack 346 of right hand side of handlebar, causing pinion 342 to rotate about its axis.

Clockwise rotation of pinion 342 (as viewed from above in Figure 4B) can be achieved by the rider/driver pushing 380 the left hand side 307 of the steering controller 305 away from them and/or by pulling 390 the right hand side 309 of the steering controller 305 back towards them. Conversely, anti-clockwise rotation of pinion 342 can be achieved by the rider/driver pushing 390 the right hand side 309 of the steering controller 305 away from them and/or by pulling 380 the left hand side 307 of the steering controller 305 back towards them. Rotation of the pinion 342 results in the rotation of the first bevel gear 314 inside the rack and pinion housing 340. Rotation of bevel gear 314 in turn results in rotation 365 of bevel gear 316 about the steering axis 360, thereby causing rotation 365 of steering linkage 350 within bush 320. Clockwise rotation of the pinion gear 342 (as viewed in the plane of Figure 4B) results in anticlockwise rotation of the steering linkage 350 (as viewed in the plane of Figure 4A), and vice versa.

The system 300 is arranged such that clockwise rotation 365 of the steering controller 305 about the steering axis 360 causes the steering linkage 350 to rotate clockwise (as viewed in the plane of Figure 4A) with the result that the one or more front (steerable) wheels of the vehicle pivot to the right, resulting in steering of the vehicle to the right, and such that pushing 380 the left hand side 307 of the steering controller 305 away from the rider (and/or or pulling 390 the right hand side 309 towards the rider) causes the one or more front (steerable) wheels of the vehicle to pivot to the left. With this set-up, the rider/driver steers the vehicle into a right- hand turn (optionally by clockwise rotation 365 of the steering controller 305 about the steering axis 360), resulting in steering of the vehicle to the right, and can momentarily push 380 the left hand side 307 of the steering controller 305 away from them (and/or pull 390 the right hand side 309 of the steering controller 305 towards them) causes the steering linkage 350 to momentarily rotate anti-clockwise (as viewed in the plane of Figure 4A, i.e. away from the direction of the turn), thereby resulting in counter steering of the vehicle to the left.

In some modified versions of the above embodiment, the system 300 may be arranged such that pushing 390 the right hand side 309 of the steering controller 305 away from the rider/driver (and/or or pulling 380 the left hand side 307 towards the rider/driver) causes the steering linkage 350 to momentarily rotate anti-clockwise (as viewed in the plane of Figure 4A, i.e. away from the direction of the turn), thereby resulting in counter steering of the vehicle to the left, and vice versa. That is, the inputs for counter steering may be reversed.

With such a set-up, the rider/driver steers the vehicle into a right-hand turn (optionally by clockwise rotation 365 of the steering controller 305 about the steering axis 360), resulting in steering of the vehicle to the right, and can momentarily push 390 the right hand side 309 of the steering controller 305 away from the rider (and/or or pull the left hand side 307 towards the rider) to cause the steering linkage 350 to momentarily rotate anti-clockwise (as viewed in the plane of Figure 4A, i.e. away from the direction of the turn), thereby resulting in counter steering of the vehicle to the left, and vice versa. In an alternative embodiment, the system 300 may be arranged such that pushing and/or pulling 380, 390 the left hand side 307 or right hand side 309 of the steering controller 305 provides for steering of the vehicle, whilst rotation of the steering controller 305 from its neutral position (as shown in Figures 4A to 4C) either clockwise (right-wise) or anticlockwise (left- wise) about steering axis 360 in the plane of Figure 4A provides for counter steering of the vehicle. In other words, rotation of pinion 342 (as viewed from above in Figure 4B) about the counter steering axis 370 may be used to effect steering of the vehicle, whilst rotation of the steering controller about the steering axis 360 effects counter steering of the vehicle.

Figures 5A to 5C show a system 400 for controlling counter steer in a vehicle utilising signals from a load cell 480. System 400 is particularly suited to motor-powered vehicles. However, system 400 could also be used in a pedal-powered vehicle, for example a four-wheeled tilting mountain bike. The system 400 comprises a steering controller 405 and a load cell 480 that is arranged to detect applied forces urging the steering controller 405 to rotate around a counter steering axis 470. The steering controller 405 is of a generally rectangular shape with openings at both the left and right hand sides 407, 409 to allow the rider/driver to readily grip the steering controller 405. Each opening has a series of undulated grips 406 to enable to the rider/driver to more comfortably and securely grasp the steering controller 405.

The steering controller 405 is able to rotate about a steering axis 460 (as described further below) to rotate a steering linkage 450 within its mounting bush 420 (or bearing or similar mounting) and thereby control steering of the vehicle. The steering controller 405 is also rotatable relative to a counter steering axis 470 that is approximately perpendicular to the steering axis 460 (though may be arranged at any angle to the steering axis 460 in other embodiments). Movement of the steering controller 405 relative to the counter steering axis 470 is detected by the load cell 480.

The load cell 480 is mounted between a rigid pivot arm 482 and the steering controller 405. The pivot arm 482 is connected to the steering linkage 450 so that it rotates in tandem with the steering controller 405 about the steering axis 460, but so that rotation of the steering controller 405 about the counter steering axis 470 results in relative movement between the steering controller 405 and the pivot arm 482, and so that this relative movement is detected by the load cell 480. A shock absorber 485 is mounted in series with the load cell 480 between the steering controller 405 and the pivot arm 482 to both enable this relative movement and dampen (i.e. smooth out) counter steering inputs from the controller 405. The system 400 is thus arranged such that right-wise rotation 475 (clockwise, as viewed in Figure 5C) of the steering controller 405 about the counter steering axis 470 results in a compressive force being applied to the load cell 480, and left-wise rotation 475 (anti-clockwise, as viewed in Figure 5C) of the steering controller 405 about the counter steering axis 470 results in a tensile force being applied to the load cell 480.

Referring to Figure 5A, the rider/driver sits in front of the steering controller 405 and faces towards the steering controller in the plane of Figure 5A. In order to steer the vehicle, the rider/driver rotates 465 the steering controller 405 from its neutral position (as shown in Figures 5A to 5C) either clockwise or anticlockwise about the steering axis 460 in the steering plane (i.e. in the plane of Figure 5A) to effect clockwise or anti-clockwise rotation, respectively, of the steering linkage 450 about the steering axis 460, in the same manner as for steering controller 305 described above in relation to Figures 4A-C.

Clockwise rotation 465 about the steering axis 460 can be achieved by the rider/driver pushing the left hand side 407 of the steering controller 405 upwards and/or by the puling the right hand side 409 of the steering controller 405 downwards. Conversely, anticlockwise rotation 465 about the steering axis 460 can be achieved by the rider/driver pushing the right hand side 409 of the steering controller 405 upwards and/or by the puling the left hand side 407 of the steering controller 405 downwards.

Rotation 465 of the steering controller 405 about the steering axis 465, results in rotation 465 of the steering controller shaft 412 about the steering axis 465. This in turn causes rotation of steering linkage 450 within its mounting bush 420. As with systems 200 and 300 described above, steering axle 450 may be linked to an electronic steering by wire system or by direct mechanical connection to one or more front (steerable) wheels of the motor-powered vehicle.

Conveniently, the system 400 is arranged such that clockwise rotation 465 of the steering controller 405 about the steering axis 460 causes the one or more front (steerable) wheels of the vehicle to pivot to the right, resulting in steering of the vehicle to the right, and anticlockwise rotation 465 of the steering controller 405 about the steering axis 460 causes the one or more front (steerable) wheels of the vehicle to pivot to the left, resulting in steering of the vehicle to the left.

In addition to steering the vehicle as described above, the rider/driver can also rotate 475 the steering controller 405 from its neutral position (as shown in Figures 5A to 5C) about the counter steering axis 470 in the counter steering plane (i.e. in the plane of Figure 5C) to effect counter steering of the vehicle. Right-wise rotation 475 of the steering controller 405 about the counter steering axis 470 (i.e. clockwise rotation as viewed in the plane of Figure 5C) can be achieved by the rider/driver pushing the left hand side 407 of the steering controller 405 away from them and/or by pulling the right hand side 409 of the steering controller 405 back towards them. This movement causes a compressive force to be applied to the load cell 480. Conversely, left-wise rotation 475 of the steering controller 405 about the counter steering axis 470 (i.e. anti-clockwise rotation as viewed in the plane of Figure 5C) can be achieved by the rider/driver pushing the right hand side 409 of the steering controller 405 away from them and/or by pulling the left hand side 407 of the steering controller 405 back towards them. This movement causes a tensile force to be applied to the load cell 480.

The load cell 480 generates an electrical signal indicative of the nature of the force applied to it, and this signal is used to control the steering linkage 450 to effect counter steer of the vehicle. In all embodiments the electrical signal is indicative of whether the force applied to the load cell 480 is compressive or tensile, but in some embodiments the signal may also indicate the degree of rotation of the steering controller 405 about the counter steering axis 470, and/or the rate of change of rotation about the counter steering axis 470. Thus, the signal sent by the load cell 480 can be set to actuate a pre-defined degree of counter-steer for a set period of time irrespective of the degree of rotation 475 of the steering controller 405 about the counter steering axis 470 (i.e. irrespective of the magnitude of the compressive or tensile force applied to the load cell 480). Alternatively, the load cell 480 can be set up to actuate a certain degree of counter steer for a certain length of time based on the magnitude of force applied to the load cell 480, the rate of change of that force, and/or the length of time for which said force is applied to the load cell 480.

The system 400 is set up such that clockwise rotation 465 of the steering controller 405 about the steering axis 460 causes clockwise rotation (as viewed in the plane of Figure 5A) of the steering linkage 450, resulting in the one or more front (steerable) wheels of the vehicle pivoting to the right and consequential steering of the vehicle to the right. Moreover, pushing the right hand side 409 (or pulling the left hand side 407) of the steering controller 405 results in left-wise rotation 475 (anti-clockwise as viewed in the plane of Figure 5C) of the steering controller 405 about the counter steering axis 470, which applies a tensile force to the load cell 408 and results in the generation of an electrical signal that momentarily rotates the steering linkage anti-clockwise (as viewed in the plane of Figure 5A) to cause the one or more front (steerable) wheels to momentarily pivot to the left, thereby resulting in counter steering of the vehicle. Similarly, anti-clockwise rotation 465 of the steering controller 405 about the steering axis 460 causes anti-clockwise (as viewed in the plane of Figure 5A) of the steering linkage 450, resulting in the one or more front (steerable) wheels of the vehicle pivoting to the left and consequential steering of the vehicle to the left. Pushing the left hand side 407 (and/or pulling the right hand side 409) of the steering controller 405 results in right-wise rotation 475 (clockwise as viewed in the plane of figure 5C) of the steering controller 405 about the counter steering axis 470, which applies a compressive force to the load cell 408 and results in the generation of an electrical signal that causes the steering linkage 450 to be momentarily rotated clockwise (as viewed in the plane of Figure 5A) to cause the one or more front (steerable) wheels to momentarily pivot to the right, thereby resulting in counter steering of the vehicle.

In modified arrangements of the above embodiment, the system 400 may be arranged such that pushing the left hand side 407 (or pulling the right hand side 409) of the steering controller 405 results in right-wise rotation 475 (clockwise as viewed in the plane of Figure 5C) of the steering controller 405 about the counter steering axis 470, which applies a tensile force to the load cell 408 and results in the generation of an electrical signal that momentarily rotates the steering linkage anti-clockwise (as viewed in the plane of Figure 5A) to cause the one or more front (steerable) wheels to momentarily pivot to the left, thereby resulting in counter steering of the vehicle, and vice versa. That is, the inputs for counter steering may be reversed.

In such arrangements, anti-clockwise rotation 465 of the steering controller 405 about the steering axis 460 causes anti-clockwise (as viewed in the plane of Figure 5A) of the steering linkage 450, resulting in the one or more front (steerable) wheels of the vehicle pivoting to the left and consequential steering of the vehicle to the left, whilst pushing the right hand side 409 (and/or pulling the left hand side 407) the steering controller 405 results in left-wise rotation 475 (anti-clockwise as viewed in the plane of figure 5C) of the steering controller 405 about the counter steering axis 470, which applies a compressive force to the load cell 408 and results in the generation of an electrical signal that causes the steering linkage 450 to be momentarily rotated clockwise (as viewed in the plane of Figure 5A) to cause the one or more front (steerable) wheels to momentarily pivot to the right, thereby resulting in counter steering of the vehicle.

Additionally, the load cell 480 can be used to send“plus” or“minus” signals to a control unit (not shown), which can cause the vehicle to lean, or have a tendency to lean, in the direction desired by the rider/driver. For example, the system 400 can be set-up so that the rate and degree of counter steering depends, at any given moment, respectively upon the rate of increase or decrease of the“plus” or“minus” signals and on the degree of rotation 475 of the steering controller 405 about the counter steering axis 475.

In modified arrangements of this embodiment, the system 400 may be arranged such that that rotation of the steering controller 405 from its neutral position (as shown in Figures 5A to 5C) either clockwise (right-wise) or anticlockwise (left-wise) about counter steering axis 470 provides for steering of the vehicle, whilst rotation of the steering controller 400 from its neutral position (as shown in Figures 5A to 5C) either clockwise (right-wise) or anticlockwise (left- wise) about steering axis 460 in the plane of Figure 4A provides for counter steering of the vehicle. In other words, rotation of the steering controller 405 about the counter steering axis 470 may be used to effect steering of the vehicle, whilst rotation about the steering axis 460 effects counter steering of the vehicle.

In all of the embodiments discussed above the steering controller 105, 205, 305, 405 may be biased towards its neutral position in the counter steering plane, i.e. the position in which it is not rotated, tilted or otherwise displaced relative to the counter steering axis (or steering plane) and so does not effect any counter steering of the vehicle. The steering controller may be biased to the neutral position by a spring or other resilient member, or other mechanical or electro-mechanical component that achieves a similar effect. Such an arrangement has the benefit of encouraging the rider/driver to gently let the steering system settle down and reach ‘equilibrium’ after applying the relatively sudden force which triggers counter steer. Moreover, in many embodiments, as the rider/driver initiates counter steer a down force component is provided to the steering controller; this down force working against the biasing mechanism provides a degree of‘counter lean’ of the vehicle.

Figures 6A to 6C show a relatively simple electro-mechanical system 500 for controlling counter steer in a vehicle comprising handlebars 505 and headset 510. The headset 510 comprises a generally U-shaped yoke portion having two upwardly-extending limbs between which the handlebars 505 pass. A counter steering shaft 555 interconnects the yoke portion of the headset 510 with the handlebars 505 such that the counter steering shaft 555 is rigidly connected to a midpoint of the handlebars 505 and the counter steering shaft 555 is rotatable within bushes or bearings in the headset 510. The handlebars have a left hand side 507 and right hand side 509. The counter steering shaft 555 thus provides a pin arrangement enabling the handlebars 505 to pivot relative to the headset 510 about a counter steering axis 570. Pivoting of the handlebars 505 about the counter steering axis 570 results directly in rotation of the counter steering shaft 555, and the degree of rotation from the neutral position can be monitored by a sub-system (not shown). This information can then be used to control an end actuator (not shown) to provide counter steer of the steerable wheel(s) and/or axle(s) of the vehicle. In some embodiments the speed of movement of the counter steering shaft 555 is also monitored and used to control the end actuator.

The headset 510 is rigidly connected to a steering linkage 550 that is rotatable within a fixed bush assembly 520, movement of which controls a steering direction of one or more wheels or axles of the vehicle. Thus, pivoting of the handlebars about a steering axis 560 substantially perpendicular to the counter steering axis results in rotation of the headset 510, and thus the steering linkage 550 to provide steering.

In Figure 6A, the rider/driver sits behind the handlebars 505 and faces the handlebars 505 in the plane of Figure 6A. In order to steer the vehicle, the rider/driver rotates 565 the handlebars 505 from their neutral position (as shown in Figures 6A to 6C) right-wise (clockwise) or left- wise (anti-clockwise) about the steering axis 560 in the steering plane (i.e. in the plane of Figure 6B).

Right-wise rotation 565 about the steering axis 560 can be achieved by the rider pushing the left hand side 507 of the handlebars 505 away from them and/or by pulling the right hand side 509 of the handlebars 505 back towards them. Conversely, left-wise rotation 565 about the steering axis 560 can be achieved by the rider pushing the right hand side 509 of the handlebars 505 away from them and/or by pulling the left hand side 507 of the handlebars 505 back towards them.

Rotation 565 of the handlebars 505 about the steering axis 560 causes the headset 515 to rotate about the steering axis 560, thereby causing steering linkage 550 to rotate 565 within the bush assembly 520. As with systems 200, 300 and 400 described above, steering linkage 550 may be linked to an electronic steering by wire system or by direct mechanical connection to one or more wheels of the vehicle.

Conveniently, the system 500 is arranged such that right-wise rotation 565 of the handlebars 505 about the steering axis 560 causes the one or more front (steerable) wheels of the vehicle to pivot to the right, resulting in steering of the vehicle to the right, and left-wise rotation 565 of the handlebars 505 about the steering axis 560 causes the one or more front (steerable) wheels of the vehicle to pivot to the left, resulting in steering of the vehicle to the left.

In addition to steering the vehicle as described above, the rider/driver can also rotate 575 the handlebars 505 from their neutral position (as shown in Figures 6A to 6C) about the counter steering axis 570 in the counter steering plane (i.e. in the plane of Figure 6A) to effect counter steering of the vehicle. Clockwise rotation 575 of the handlebars 505 about the counter steering axis 570 can be achieved by the rider/driver pressing the right hand side 509 of the handlebars 505 downwards and/or by pulling the left hand side 507 of the handlebars 505 upwards. Conversely, anticlockwise rotation 575 of the handlebars 505 about the counter steering axis 570 can be achieved by pressing the left hand side 507 of the handlebars 505 downwards and/or by pulling the right hand side 509 of the handlebars 505 upwards.

Rotation 575 of the handlebars 505 about the counter steering axis 570 causes the counter steering axle 555 to rotate 575 about the counter steering axis 570. As with the steering linkage 550, the counter steering axle 555 may be linked to an electronic steering by wire system or by direct mechanical connection to one or more wheels of the vehicle. Conveniently, the system 500 is arranged such that clockwise (right-wise) rotation 575 of the handlebars 505 about the counter steering axis 570 causes the one or more front (steerable) wheels of the vehicle to pivot to the left, resulting in counter steering of the vehicle to the left, and anticlockwise (left-wise) rotation 575 of the handlebars 505 about the counter steering axis 570 causes the one or more front (steerable) wheels of the vehicle to pivot to the right, resulting in counter steering of the vehicle to the right.

The system 500 is set up such that right-wise rotation 565 of the handlebars 505 about the steering axis 560 causes the one or more front (steerable) wheels of the vehicle to pivot to the right, resulting in steering of the vehicle to the right, and such that momentarily pressing down on the right hand side 509 of the handlebars 505 (and/or pulling the left hand side 507 upwards) results in clockwise rotation 575 of the handlebars 505 about the counter steering axis 570, causing the one or more front (steerable) wheels of the vehicle to momentarily pivot to the left, thereby resulting in counter steering of the vehicle.

In some embodiments, a sub system (not shown) monitors the degree of rotation 575 of the handlebars 505 from their neutral position (as shown in Figures 6A to 6C) about the counter steering axis 570 and the rate of increase or decrease in the speed of movement of the handlebars 505 about the counter steering axis 570 at any given moment. This data can be fed into a computer which controls one or more actuators connected to each of the one or more wheels of the vehicles. This can result in the vehicle leaning, or having a tendency to lean, in the direction desired by the rider/driver.

In modified versions of the illustrated embodiment, the system 500 may be arranged such that rotation of the handlebars 505 from their neutral position (as shown in Figures 6A to 6C) either clockwise (right-wise) or anticlockwise (left-wise) about counter steering axis 570 provides for steering of the vehicle, whilst rotation of the handlebars 505 from their neutral position (as shown in Figures 6A to 6C) either clockwise (right-wise) or anticlockwise (left-wise) about steering axis 560 in the plane of Figure 6B provides for counter steering of the vehicle. In other words, rotation of the handlebars 505 about the counter steering axis 570 may be used to effect steering of the vehicle, whilst rotation about the steering axis 560 effects counter steering of the vehicle.

Figure 7 shows a rear view of a stabilising system 600 for a motorbike that mimics a rider 610 counter leaning. The stabilising system 600 is appropriate for any tilting vehicle having two or more road wheels.

The stabilising system 600 is particularly suitable for use in conjunction with any of the previously described systems for controlling counter steer. In particular, the handlebars 605 of this embodiment may be configured as the steering controller or handlebars of any of the previously described embodiments, and the rotation, displacement or other movement of the steering controller or handlebars about the counter steering axis may trigger both the system for controlling counter steer 100, 200, 300, 400, 500 and the stabilising system 600.

The stabilising system 600 operates by moving a portion of the tilting vehicle a small distance towards the outside of a bend or corner around which the vehicle is travelling. In the embodiment of Figure 7, the seat 620 is mounted on linear guides 630 and can be moved by an actuator 640 in response to rotation, displacement or other movement of the steering controller or handlebars about the counter steering axis. However, the moved portion could also for example be the battery, oil tank, or roll cage of the vehicle.

Movement of the seat 620 (or other moveable portion) initiates counter lean towards the outside of the turn, and consequential tilting of the vehicle towards the inside of the turn. For example, when a rider 610 and their seat 620 temporarily move to the left in the plane of Figure 7 (as indicated by the direction of the arrow), lean of the vehicle to the right can be triggered by the rider 610 consciously or sub-consciously applying a downward force to the right hand side 609 of the handlebars 605 and/or the right hand footrest (or by actively moving the handlebars relative to the counter steering axis, as described above). The mass of the rider, and their relatively high centre of gravity, results in right hand lean of the vehicle (which has a relatively low centre of gravity). This lean to the right triggers gyroscopic precession of the steerable wheels, which, in turn, causes or has a tendency to cause turning of the vehicle to the right. Thus, stabilising system 600 mimics the effect of the known process of counter leaning.

Depending on the general design layout of the vehicle, an alternative to the electro-mechanical embodiment described above would be the use of a Bowden cable which has one end attached to the handlebars 605 and the other end attached to the rider’s seat 620.

As the tilting vehicle gains forward speed it will demonstrate greater reluctance to change its tilt orientation. This is owing to the reluctance of the spinning wheels to lean either way as their rotational speed increases. Therefore, the stabilising system 600 may be less effective when the vehicle is travelling at high speed. This problem may be alleviated by utilising a delayed counter lean response, as described below.

After the handlebars have been moved away from their“neutral” position in the counter steer plane, there could be a delay (of fractions of a second) before the counter lean system is activated. As a result, initial counter steer of the front and/or rear wheel(s) provided by the system for providing counter steer 100, 200, 300, 400, 500 will“break” the reluctance of the wheels to lean and, once the vehicle is tilting in the desired direction, the counter lean system will be more effective.

Figure 8 shows a stabilising system 700 for facilitating tilt of a vehicle having three or more road wheels. The stabilising system 700 acts to provide controlled resistance to vehicle tilt away from the desired tilt direction.

The stabilising system 700 can be applied to the front and/or back axles of a vehicle. It is particularly suitable for use in conjunction with any of the previously described systems for controlling counter steer. In particular, activation of the stabilising system 700 in the sideways direction desired by the rider/driver may be triggered by the rotation, displacement or other movement of the steering controller or handlebars of any of the previously described embodiments about the counter steering axis. Thus, the steering controller or handlebars may trigger the system for controlling counter steer and/or the stabilising system 700.

The stabilising system 700 comprises a central column 710 to which an axle assembly 720 is attached. The central column 710 also supports a main frame or chassis (not shown) of the vehicle. The axle assembly 720 is made up of four axle linkages 730 pivotally connected to each other at pivot points 740 at the ends thereof to form a four-sided polygon that comprises four bars and six pivots. When the vehicle is upright, the axle assembly 720 is generally rectangular in shape and when the vehicle is leaning generally forms a parallelogram, with the two side linkages 730 leaning relative to vertical and the upper and lower linkages 730 remaining generally horizontal. Midpoints of the upper and lower linkages are also connected pivotally to the central column 710 by two further pivot points 740. In this way, by controlling the configuration of the axle assembly 720 the tilt of the wheels 750 of the vehicle, and thereby the tilt of its main frame or chassis, can be controlled.

The stabilising system 700 comprises a hydraulic system 760, comprising a hydraulic cylinder 770 comprising a piston 771 movable within a cylinder barrel 772, the piston being rigidly connected to a piston rod 773. The piston rod 773 is connected to the upper linkage of the axle assembly 720 such that movement of the piston 771 within the cylinder barrel 772 is able to influence the geometry of the axle assembly 720. The hydraulic system thereby provides controlled resistance to movement of the axle assembly 720 away from the desired tilt direction, such that the sideways orientation of the vehicle changes or has a tendency to change only to the orientation desired by the rider/driver.

Movement of the steering controller about the counter steering axis controls the state of each of two remotely controlled hydraulic valves 765a, 765b, each of which is associated with a corresponding hydraulic check valve that acts to permit movement of hydraulic fluid in one direction only. When the steering controller is in its neutral position both valves 765a, 765b are closed. Movement of the steering controller about the counter steering axis in a first direction (e.g. clockwise movement relative to the rider/driver) causes one of the valves 765a to close and the other 765b to open, such that the axle assembly 720 is only able to change geometry to permit tilt of the vehicle in a first direction (e.g. to the right). Similarly, movement of the steering controller about the counter steering axis in a second direction opposite to the first direction (e.g. anticlockwise movement relative to the rider/driver) causes the valve 765a to open and the other valve 765b to close, such that the axle assembly 720 is only able to change geometry to permit tilt of the vehicle in a first direction opposite to the second direction (e.g. to the left). The stabilising system 700 thus provides controlled resistance to vehicle movement away from the desired tilt direction, i.e. biased damping.

Tilt in the desired direction may be facilitated by vibration within the vehicle chassis and/or movement of the axle assembly 720 relative to the chassis triggering initial movement of the piston 771 within the cylinder barrel 772, this initial movement being perpetuated by the flow of hydraulic fluid as the hydraulic cylinder 770 attempts to‘overrun’.

An electronic“by wire” system could be used such that when the relevant side of the steering control system is pushed down (i.e. the steering controller is moved with respect to the counter steering axis), the force exerted by the device is greater the further the steering controller is pushed away from the neutral position. Thus, each of the remotely controlled hydraulic valves 765a, 765b may have a continuous range of valve positions between‘closed’ and‘fully open’ positions, and the valve position may correspond to the displacement of the steering controller relative to the neutral position. When a respective one of the valves 765a, 765b is in the‘fully open’ position it offers a minimum resistance to vehicle tilt, with resistance to tilt increasing towards the‘closed’ position.

At lower speeds below a predetermined threshold the valve position of the valves 765a, 765b may be continuously varied between fully open and fully closed positions, as described above. At speeds above the threshold the valves may be always fully open.

Although the force acting device 770 is likely to be used often, most situations will dictate it is only used momentarily. Despite this, it may be necessary to ensure that when the vehicle travels at speed over rough terrain, the relevant set force, determined by the orientation of the handlebars, will be maintained despite any change in geometry of the axle assembly 720 caused by uneven ground.

Figure 9 is a schematic rear view of a rear axle assembly of a three-wheeled tilting vehicle comprising a stabilising system 800 for tilting vehicles with three or more road wheels 850. Figure 10 is a front view of a front axle assembly of the vehicle of Figure 9. Thus, the vehicle in the illustrated embodiment has a single front wheel and two rear wheels. In other embodiments the vehicle may have two front wheels and a single rear wheel, for example.

A stabilising system 800 according to this embodiment can be linked to system 100 for controlling counter steer described above in relation to Figures 1A to 1 C. In this example, wheel 135 of system 100 is the front wheel of the vehicle, and wheels 850 of system 800 are the rear wheels, and thus together form a three-wheeled vehicle.

The stabilising system 800 provides a means by which a momentary (i.e. temporary, for a limited short duration) rotation of the steering controller (handlebars) 105 in the counter steering plane (i.e. rotation in the direction of arrow 175 about counter-steering axis 170) can trigger both counter-steering of the front wheel (or rear wheel in embodiments with a single rear wheel) and tilting of the vehicle via control of the geometry of the rear axle assembly (or front axle assembly in embodiments with two front wheels). In addition, or alternatively, it enables a relatively small input force and/or relatively small degree of input movement (i.e. a relatively small movement of the steering controller) to be magnified to provide a relatively high degree of tilt of the tilting axle assembly via a purely mechanical system, without any requirement for power from the vehicle’s battery, generator, engine or other onboard power source. Thus, the stabilising system 800 is expected to be particularly beneficial for electric vehicles, where limited battery power may be available.

The vehicle has a tilting axle assembly 820 made up of four axle linkages 830 pivotally connected to each other at pivot points 840 at the ends thereof to form a four-sided polygon that comprises four bars and six pivots. When the vehicle is upright, the axle assembly 820 is generally rectangular in shape and when the vehicle is leaning generally forms a parallelogram, with the two side linkages 830 leaning relative to vertical and the upper and lower linkages 830 remaining generally horizontal. Midpoints of the upper and lower linkages are also connected pivotally to the central column 810 by two further pivot points 840. In this way, by controlling the configuration of the tilting axle assembly 820 the tilt of the wheels 850 of the vehicle, and thereby the tilt of its main frame or chassis, can be controlled.

Stabilising system 800 comprises a linear carriage 874 and linear guide 876 having an interface 872 between them such that the linear carriage 874 is movable relative to the linear guide 876 along a linear path. Movement of the linear carriage 874 relative to the linear guide 876 is thus capable of providing direct control of the tilt of the vehicle’s axle assembly 820 relative to the vehicle’s chassis (not shown). A rigid arm 881 is rigidly connected to the linear carriage 874 via fixing 880. The arm 881 connects the linear carriage 874 with a central column 810 of the vehicle chassis that itself is attached to the vehicle’s axle assembly 820 at upper and lower pivot points 840. The linear position of the carriage 874 relative to the guide 876 is controlled via the positions of tension cables 883a, 883c (see Figures 9 and 10), each of which connects the vehicle’s handlebars 105 to the linear carriage 874. The left hand cable 883c connects to the left hand side 107 of the handlebars 105 and is arranged such that tension therein causes the linear carriage 874 to be urged upwards (as viewed in Figure 9) along the linear guide 876, and the right hand cable 883a connects to the right hand side 109 of the handlebars 105 and is arranged such that tension therein causes the linear carriage 874 to be urged downwards (as viewed in Figure 9) along the linear guide 876. A cable fixing 882 connects the cables 883a, 883c to the arm 881 , to thereby provide the connection with the linear carriage 874. Each cable 883a, 883c is movable within a fixed outer cable sheath in a conventional arrangement.

The linear guide 876 is rigidly attached to the cylinder barrel 878 of hydraulic cylinder 870. The hydraulic cylinder 870 includes a piston 871 that is movable within the cylinder barrel 878. The piston 871 is connected to a piston rod 879 of the hydraulic cylinder 870 that is attached to the vehicle’s axle assembly 820 by a fixing 884. Thus, relative movement between the linear carriage 874 and linear guide 876 can directly influence movement of the piston rod 879, and thus tilting of the tilting axle assembly 820, when movement between the piston 871 and cylinder barrel 878 is prevented. Moreover, a hydraulic control system 886 can provide a greater degree of tilting, and increased rate of change of tilting, by enabling relative movement between the piston rod 879 and the cylinder barrel 878, as described further below.

Stabilising system 800 has a remote control system (not shown) that monitors the angle of rotation of the vehicle’s handlebars 105 (see Figure 10) about the counter steering axis 170, and ensures that a directional control valve 888 (see Figure 9) of the hydraulic control system 886 is in its appropriate set position. The directional control valve 888 has three set operational positions: a central (neutral) position 890n; a first valve position 890c; and a second valve position 890a.

The remote control system is configured to set the directional control valve 888 to its central position 890n when the steering controller (handlebars) 105 are in their neutral position relative to the counter-steering plane and counter steering axis 170. When the handlebars 105 are moved beyond a predetermined boundary relative to the counter-steering axis 170 in a clockwise direction (relative to the rider/driver) the remote control system is configured to set the directional control valve 888 to its first valve position 890c. Similarly, when the handlebars 105 are moved beyond a corresponding predetermined boundary relative to the counter steering axis 170 in an anti-clockwise direction (relative to the rider/driver) the remote control system is configured to set the directional control valve 888 to its second valve position 890a. An example of the predetermined boundaries discussed above is illustrated in Figure 10. When the handlebars 105 are moved anti-clockwise (relative to the rider/driver) beyond the dashed line A in the counter steering plane (i.e. in the plane of Figure 10), the directional control valve 888 is changed to the second valve position 890a. Similarly, if the handlebars are moved clockwise (relative to the rider/driver) beyond the dashed line B, directional control valve 888 will be changed to the first valve position 890c. In other words, movement of the handlebars 105 in either direction beyond a predetermined threshold triggers the directional control valve 888 to adopt the first valve position 890c or second valve position 890a. In this embodiment this is achieved by means of a remote control system connected to directional control valve 888 that monitors the angle of rotation of the vehicle’s handlebars 105 about the counter steering axis 170.

In the first valve position 890c hydraulic fluid can flow through the hydraulic control system 886 via a first check valve 892c in a first direction. Similarly, in the second valve position 890a hydraulic fluid can flow via a second check valve 892a in a second direction opposite to the first direction. In this way, the first valve position 890c allows movement of the piston 871 relative to the cylinder barrel 878 in one direction only (downwards in the plane of Figure 9), and the second valve position 809a allows movement of the piston 871 relative to the cylinder barrel 878 in the other direction only (upwards in the plane of Figure 9).

When directional control valve 888 is in the central position 890n, hydraulic fluid within the hydraulic control system 886 is unable to flow in any direction through the hydraulic control system 886 and so the piston 871 of the hydraulic cylinder 870 is prevented from moving relative to the cylinder barrel 878 (i.e. the hydraulic cylinder 870 is locked in place). Thus, movement of the handlebars 105 about the counter steering axis 170 is capable of resulting in only very limited tilting of the vehicle in the direction desired by the rider/driver as a result of relative movement between the linear carriage 874 and linear guide 876. For example, if the rider applies a downward force to the right hand side 109 of the handlebars 105 (Figure 10), then the left hand cable 883c (see both Figures 9 and 10) is put under tension. Thus the arm 881 is pulled upwards to move the linear carriage 874 upwards along the linear guide 876 in the plane of Figure 9, causing corresponding downwards movement of the hydraulic cylinder 870 and piston rod 879, and thereby resulting in a change in geometry of the vehicle’s axle assembly 820. This causes the vehicle to tilt, or to have a tendency to tilt, to the right in the plane of Figure 9 (i.e. clockwise from the rider’s perspective - the rider facing into the plane of Figure 9) into the turn. By the opposite process, the vehicle is caused to tilt, or have a tendency to tilt, to the left in response to a downward force applied to the left hand side 108 of the handlebars 105, which results in an increase in tension of the right hand cable 883a. In this configuration (when the directional control valve is in the central valve position 890n) a limited degree of tilt is directly controlled by the rider/driver.

Therefore, when the directional control valve 888 is in the central position 890n, there is a direct correlation between the degree of rotation of the handlebars 105 about the counter steering axis 170 and the angle of tilt of the vehicle throughout the range of rotation of the handlebars 105 about the counter steering axis 170. However, bearing in mind the mechanical advantage involved, and the limited angular range of rotation the handlebars 105 about the counter steering axis 170 (which could be, for example, 45° clockwise and anti-clockwise), it may not be possible for the rider to achieve the desired maximum angle of tilt (i.e., the maximum angle of tilt of the vehicle could prove to be inadequate) in this configuration. Thus, the hydraulic control system 886 described below can provide a greater degree of tilting by enabling relative movement between the piston rod 879 and the cylinder barrel 878 when the directional control valve 888 is in the first 890c or second 890a valve position.

In preferred embodiments the predetermined boundaries A and B are set such that any small (de minimis, or negligible) movement of the handlebars 105 resulting from accidental, or non- deliberate, movement relative to the counter-steering axis 170 (e.g. as a result of travelling over rough terrain) will not cause the directional control valve 888 to switch from the neutral valve position 890n to the first 890c or second 890a valve positions. This is to avoid such accidental movements resulting in rapid, unwanted switching of the directional control valve 888 that may lead to a loss of performance or system failure. Thus, in such preferred embodiments all intentional movement of the handlebars 105 relative to the counter-steering axis 170 (i.e. all movement greater than an amount considered to be likely to result from accidental or unintentional movement) will result in switching of the directional control valve 888 to either the first 890c or second 890a valve position, as appropriate.

When the directional control valve 888 is changed to the first valve position 890c, due to the rider applying a downward force to the right hand side 109 of the handlebars 105 (Figure 10) such the handlebars 105 are moved beyond the dashed line B (see Figure 10) in the counter steering plane (i.e. in the plane of Figure 10), hydraulic fluid can flow around the hydraulic control system 886 via first check valve 892c such that fluid flow in only a first direction (a clockwise direction as viewed in Figure 9). Thus, the piston 871 is able to move downwards relative to the cylinder barrel 878 only, i.e. the cylinder barrel 878 is able to move upwards relative to the piston 871 in the plane of Figure 9 to enable tilting of the vehicle to the right. Similarly, when the directional control valve 888 is changed to the second valve position 890a, due to the rider applying a downward force to the left hand side 107 of the handlebars 105 (Figure 10) such that the handlebars 105 are moved beyond the dashed line A (see Figure 10) in the counter steering plane (i.e. in the plane of Figure 10), hydraulic fluid can flow around the hydraulic control system 886 via second check valve 892a such that fluid flow in only a second direction opposite to the first direction (an anti-clockwise direction as viewed in Figure 9) is possible. Thus, the piston 871 is able to move upwards relative to the cylinder barrel 878 only, i.e. the cylinder barrel 878 is able to move downwards relative to the piston 871 in the plane of Figure 9 to enable tilting of the vehicle to the left.

In preferred embodiments the handlebars 105 (steering controller) is moved beyond the predetermined boundary A or B about the counter-steering axis only momentarily, or temporarily. The rider may apply significant force to the handlebars 105 to effect such movement, thus transmitting a correspondingly significant momentum to the linear carriage 874. This momentum is then transmitted to the hydraulic cylinder barrel 878. Since the directional control valve 888 is in the first 890c or second 890a valve position this force results in relative movement between the cylinder barrel 878 and the piston 871 , this relative movement resulting in turn in movement of the hydraulic fluid. The momentum in the fluid itself causes the hydraulic cylinder 870 to‘overrun’ by way of hydraulic check valves 892a, 892c letting hydraulic oil flow freely by. Even when the handlebars 105 are moved the slightest distance beyond either boundary A or B, the momentum triggered can be such that the vehicle continues to tilt at a rate, and in a direction, desired by the rider, after the triggering input of movement of the handlebars 105 is removed.

It is possible, therefore, for momentary, temporary, rotation of the handlebars 105 about the counter steering axis 170 to simultaneously activate the stabilising system 800 and trigger counter steering. That is, movement of the handlebars 105 relative to the counter steering plane can activate both the counter steering system as described in the above embodiments and the stabilising system 800.

Whilst the vehicle continues to tilt in the manner desired by the rider, the handlebars 105 can, optionally relatively slowly, be returned towards their neutral configuration (i.e. as shown in Figure 10). It is important to note that, in this embodiment, the hydraulic control system 886 does not return the directional control valve 888 to its central position 890n until the handlebars are returned to their neutral configuration. Once the directional control valve 888 is returned to the central position 890n further relative movement between the piston 871 and cylinder barrel 878 is prevented, and the direct control over vehicle tilt is thus maintained.

To return to an upright, non-tilted, position the rider/driver must rotate the handlebars 105 about the counter-steering axis 170 in the opposite direction to the direction of rotation applied to effect the tilt. For example, when the vehicle is tilting to the right the rider/driver would rotate the handlebars 105 anti-clockwise (relative to the rider/driver) by applying a downwards force to the left hand side 107 thereof to instigate tilt towards the left-hand direction.

Stabilising system 800 is configured such that the rider does not need to use excessive force to carry out the process described above. In other words, the points at which the left hand cable 883c and right hand cable 883a are attached to the handlebars 105, and the position of the fixing 884 of hydraulic cylinder 870 to the vehicle’s axle assembly 820, are such that there is adequate mechanical advantage (the rider does not need apply too much force to the handlebars 105 to effect leaning of the vehicle). When the rider applies a downward force to the right hand side 109 of the handlebars 105, the vehicle will continue to tilt, or to have a tendency to tilt, to the right even after the handlebars are rotated, relatively slowly, about the counter steer axis 170 back to the neutral position as shown in Figure 10.

In a situation where the rider/driver becomes aware that they are tilting too fast to the right (for example), then a relatively fast anti-clockwise rotation about the counter steer axis 170 can compensate for this. Alternatively, if circumstances permit, the steering controller can be simultaneously turned to the left (anti-clockwise) about the steering axis 160 in order to compensate for the anti-clockwise rotation about the counter steer axis. This is not such an issue for a vehicle incorporating a stabilising system as described herein, as such a vehicle would require a lesser degree of counter steer to initiate leaning than a vehicle without such a stabilising system.

The gyroscopic precession forces produced by the steerable wheel(s) of a tilting vehicle (i.e. wheel 135 in the above example), when being counter steered at low speed, are minimal. The key purpose of the stabilising system 800 is to provide vehicle stability throughout this low speed range. Ideally, to demonstrate that it will be possible for a vehicle to“seamlessly” slow down to a halt from high speed and accelerate back up to high speed without the rider/driver feeling the need to put their feet on the ground. This is to be possible while bends are negotiated. There are various ways the system 800 could be engineered, including wide use of basic mechanical components, by utilising“by wire” technology, or by the mainly hydraulic approach discussed above.

For vehicles that are likely to cover rough terrain or occasionally encounter large bumps at high speed, inclusion of a hydraulic oil flow restricting device 893 (see Figure 9) would be beneficial. A simple approach would be for hydraulic oil flow restricting device 893 to be fully closed (and directional control valve 888 therefore acting to control fluid flow as described above) unless the vehicle goes above a predefined speed, for example somewhere between 15 and 20 mph. Above this predefined speed the hydraulic oil flow restricting device 893 opens fully, thereby allowing hydraulic fluid to bypass the directional control valve 888.

When the hydraulic flow restricting device 893 is fully open the hydraulic fluid is free to flow around the hydraulic control system 886 in both the clockwise and anti-clockwise directions (in the plane of Figure 9), and so the piston 871 can move both upwards and downwards relative to the cylinder barrel 878, i.e. the cylinder barrel 878 is able to move both downwards and upwards relative to the piston 871 in the plane of Figure 9. Thus, the rate of change of tilt of the vehicle is slowed by the dampening effect of the hydraulic cylinder 870 throughout the whole range of movement of the handlebars 109 from the neutral position. In such a set-up, the counter steer system would be functioning at all speeds, but only effective at moderate speed and above; and the stabilising system 800 would not function above the predetermined speed at which flow restricting device 893 is opened, other than to optionally provide a (potentially variable; see below) damping effect to the rate of change of vehicle tilt.

A more sophisticated arrangement provides for a seamless approach where hydraulic oil flow restricting device 893 is opened gradually. One option is that hydraulic oil flow restricting device 893 is fully open only at a specific moderately high forward speed. Another option is for hydraulic oil flow restricting device 893 to never fully open, i.e. it continues to restrict oil flow, therefore the stabilising system 800 (via the directional control valve 888) continues to have some (relatively small) influence over the control of vehicle stability/tilt up to, and including, top vehicle speed. A fully automatic control system (not illustrated) may be necessary to continuously monitor the vehicle’s forward speed and ensure that hydraulic oil flow restricting device 893 is always at its pre-programmed setting for any given speed.

For tilting vehicles negotiating very rough terrain, the system 500 shown in Figures 6A to 6C, in conjunction with this stabilising system 800, could prove particularly beneficial. In particular, movement of the handlebars 505 could initiate counter steer of the front and/or rear wheel(s) but not until the vehicle travels above a pre-determined forward speed (such as between 15 and 20 mph). The rider/driver is, therefore, free at low vehicle speed to help maintain stability by vigorously rotating the handlebars to activate the stabilising system 800 without causing disruptive/inappropriate turning of the steerable wheel(s).

Figure 9A illustrates a possible alternative hydraulic control system 886a that can replace the hydraulic control system 886 illustrated in Figure 9. All other elements of the stabilising system 800 remain unchanged in this embodiment.

Movement of the steering controller about the counter steering axis controls the state of each of two remotely controlled hydraulic valves 896a, 896c, each of which is associated with a corresponding hydraulic check valve that acts to permit movement of hydraulic fluid in one direction only. A flow regulator valve 894 is operable to control the flow of hydraulic fluid in either direction.

Below a predetermined threshold forward speed of the vehicle, the flow regulator valve 894 is fully closed. Then, during a transition phase (between 10mph and 20 mph, for example) the flow regulator valve 894 opens progressively. From the end of the transition phase to maximum vehicle speed the flow regulator valve 894 is fully open (or open to a predetermined degree) and causes only minor restriction to the flow of hydraulic fluid.

When the steering controller is in its neutral position both hydraulic valves 896a, 896c are open, and offer little or no restriction to hydraulic fluid flow, and therefore little or no resistance to movement of the piston 871 within the cylinder barrel 878. As the controller is moved away from neutral, the relevant valve 896a, 896c is progressively closed to offer progressively more resistance to hydraulic fluid flow.

Thus, movement of the steering controller about the counter steering axis in a first direction (e.g. clockwise movement relative to the rider/driver) causes one of the valves 896a to progressively close and the other 896c to progressively open, such that the axle assembly 820 is only able to change geometry to permit tilt of the vehicle in a first direction (e.g. to the right). Similarly, movement of the steering controller about the counter steering axis in a second direction opposite to the first direction (e.g. anticlockwise movement relative to the rider/driver) causes the valve 896a to progressively open and the other valve 896c to progressively close, such that the axle assembly 820 is only able to change geometry to permit tilt of the vehicle in a second direction opposite to the first direction (e.g. to the left). The hydraulic control system 886a thus provides controlled resistance to vehicle movement away from the desired tilt direction.

This arrangement ensures that below the predetermined threshold forward speed the driver/rider has direct control over the angle of tilt of the vehicle via relative movement between the linear carriage 874 and linear guide 876, as described above. At speeds above this threshold they have good control over the counter steering system and the stabilising system 800. This arrangement may particularly alleviate potential problems linked to encountering bumpy terrain at high speed.

A particular advantage of this hydraulic control system 886a is that it removes the need for the predetermined boundaries A, B of the steering controller, since the absence of the directional control valve 888 in the hydraulic control system 886a means that there is no requirement to prevent accidental movements of the steering controller from resulting in rapid, unwanted switching of the directional control valve 888 as described above.

Figure 1 1 shows a known three wheeled vehicle 900, which is disclosed in EP0606191. Three wheeled vehicle 900 has a single front wheel 935 and two rear wheels 936, and comprises a balancer 940 and shock absorber 945 attached to a frame 950. The balancer 940 facilitates tilting of the rear wheels 936. The front wheel 935 is attached to front forks 925 by axle 930. The front forks are directly and rigidly attached to headset 915. Headset 915 is comprised of two plates 916 and two tubes 917. Head tube 920 is rigidly attached to headset 915, being sandwiched between plates 916. Head tube 920 is moveably attached to frame 950. Head tube 920 allows the headset 915 to be moved relative to the frame 950.

Figure 12 shows a rear view of the three wheeled vehicle 900 shown in Figure 1 1 that has been modified to comprise a system for controlling counter steer 901. The system 901 for controlling counter steer comprises handlebars 905 and bevel gear housing 910, and head portion 920. Within the bevel gear housing 910, the handlebars 905 are coupled to headset 915 by a bevel gear connection like that shown in either Figure 1C or Figure 2.

In Figure 12, a person riding the motorbike, i.e. the rider (not shown) sits in front of the handlebars 905 and faces the handlebars 905 in the plane of Figure 12. The handlebars 905 have a left hand side 907 and a right hand side 909 with respect to the rider. In order to steer the three wheeled vehicle 900, the rider rotates 965 the handlebars 905 from their neutral position (as shown in Figure 12) either left-wise (anti-clockwise) or right-wise (clockwise) about the steering axis 960.

Right-wise rotation 965 about the steering axis 960 can be achieved by the rider pushing the left hand side 907 of the handlebars 905 away from them and/or by pulling the right hand side 909 of the handlebars 905 back towards them. Conversely, left-wise rotation 965 about the steering axis 960 can be achieved by the rider pushing the right hand side 909 of the handlebars 905 away from them and/or by pulling the left hand side 907 of the handlebars 905 back towards them.

Rotation 965 of the handlebars 905 causes the whole bevel gear housing 910 to rotate about the steering axis 965, which results in rotation 965 of the headset 915 and about the steering axis, and thus causes front fork 925 and front wheel 935 to pivot. As a result, the three wheeled vehicle 900 changes direction and steers to the left or to the right. The three wheeled vehicle 900 will continue steering to the left or to the right until the rider moves the handlebars 905 back to the starting position, i.e. back into the plane of Figure 12.

In addition to steering the three wheeled vehicle 900, the rider can also press downwards (or pull upwards) on either the right hand side 909 or left hand side 907 of the handlebars 905 to effect counter steering of the three wheeled vehicle 900. Pressing down on either the right hand side 909 or left hand side 907 of the handlebars 905 results in rotation 975 of the handlebars 905 about a counter steering axis 970 in the counter steering plane (i.e. in the plane of Figure 12). This causes rotation of the bevel gears (not shown) inside the bevel gear housing 910 (as described above in relation to either Figure 1 C and Figure 2), which causes the headset 915 to rotate 965 about the steering axis 960, thereby causing the front fork 925 and front wheel 935 to pivot to either to the left or to the right.

In an embodiment, pressing down on right hand side 909 of the handlebars 905 results in left- wise rotation 965 about the steering axis 960 such that the front fork 925 and front wheel 935 pivots to the left. With this set-up, the rider steers the three wheeled vehicle 900 into a right- hand turn (optionally by right-wise rotation 960 of the handlebars 905 about the steering axis 965 to pivot the front wheels 935 to the right), and momentarily pressing down the right hand side 909 of the handlebars 905 results in rotation 975 about the counter steering axis 970 and causes the front wheel 935 to momentarily pivot to the left, thereby resulting in counter steering of the three wheeled vehicle 900. As mentioned previously, counter steering left when steering right into a right-hand turn (and vice versa) can be counter-intuitive to less experienced riders. Therefore, by providing a system 900 wherein pressing down on right hand side 909 of the handlebars 905 causes counter steer of the three wheeled vehicle 800 to the left, and vice versa, the system 901 presents the rider with an instinctive means of control of the three wheeled vehicle 900. Moreover, momentarily counter steering the three wheeled vehicle 900 left, when steering right into a right-hand turn, causes the three wheeled vehicle 900 to lean towards to the right- hand turn, thereby tilting the three wheeled vehicle 900 and giving the rider better control of the three wheeled vehicle 800 in the turn.

The systems for controlling counter steer described above should prove particularly beneficial for vehicles that are susceptible to sudden cross winds such as vehicles offering full weather protection. In such vehicles gyroscopic precession forces from the front and rear road wheels act against the resultant wind load which hits the vehicle well behind the front wheel(s).

In some embodiments, a fully enclosed vehicle offering full weather protection may include a counter lean stabilising system, a rear axle assembly capable of offering counter steer and/or a rear axle assembly linked to an actuator system. Each of these systems provides a stabilising force that is exerted well to the rear of the front wheel(s).

Furthermore, any rider/driver travelling at high speed is fearful of having a puncture, particularly in a front wheel, since a loss of control may result. In relation to any vehicle with two or more road wheels, the rider/driver finding themselves in such a circumstance will have far more control if the vehicle incorporates a counter lean stabilising system, a rear axle assembly capable of offering counter steer and/or a rear axle assembly linked to an actuator system.

Gyroscopic precession depends for its strength on the speed of movement (i.e. speed of “turn”) of the road wheel, rather than on the amount of movement. The necessary maximum “turn” of the vehicle’s rear wheel(s) should, therefore, be very small and it should be possible for the vehicle to be designed with negligible negative effect on its overall steering characteristics.

When a racing rider/driver negotiates a bend they move the steering controller relatively quickly, but over a relatively few degrees of rotation, to initiate counter steer. Then, as the vehicle leans the racer can make several other adjustments, including slower movement of the steering controller and adjusting the torque transmitted by the rear wheel. The theory behind the reasons for these adjustments is very complex and involves several factors including camber thrust, the effective cone radius of each wheel, slip angle of each wheel, the vehicle's sliding angle, and gyroscopic precession effect of the wheels.

A vehicle, for example a racing motorbike, could be designed to include a system which has a rear wheel providing counter steer, as detailed herein. Compared to a conventional motorbike racer, the rider will have a wider range of control over many variables/factors, including those listed in the preceding paragraph. Apart from controlling counter steer of the rear wheel, by moving the steering controller relatively quickly about the counter steer axis, the racer could control the steering of the rear wheel by moving the steering controller relatively slowly about the counter steer axis. In this way, the direction in which any increase or decrease in torque is transmitted from the rear wheel, relative to the position of the machine's centre of gravity, can be altered.

The average winner of a race fielding machines of this design, with so many variables under their control, is therefore likely to have greater natural racing talent than the average winner of conventional races.

An alternative racing formula, incorporating machines with pivoting rear wheels, could be based on any design of tilting vehicle having two or more road wheels. And optimally designed and developed machines could prove to be quicker at negotiating bends than conventional racing motorbikes. There could also be beneficial "spin offs" for public road motorbikes/tilting vehicles.