This invention relates to the field of electrical engineering.

Particularly, this invention relates to a system for synchronizing speed- dependent and tuming-radius-dependent movement between a driver component and a driven component.

BACKGROUND OF THE INVENTION:

Towing is coupling two or more objects together so that they may be pulled by a designated power source or sources. The towing source may be a motorized land vehicle, vessel, animal, or human, the load anything that can be pulled.

These may be joined by a chain, rope, bar, hitch, three-point, fifth wheel, coupling, drawbar, integrated platform, or other means of keeping the objects together while in motion.

A trailer, coupled to the tractor / towing vehicle, is a driven component while the tractor / towing vehicle is a driver component. The driver component and the driven component are not necessarily, always, in sync. In case of towing of equipment, in long length in hilly areas, towing vehicles always face problems of turning circle radius and road width because of U bends, short turns, and narrow road width. This results in a lot of to and fro motion to negotiate turns, frequent hooking, and unhooking and slow movement of the unit which results in more time requirement.

When any equipment is used as a semi-trailer it has a bigger turning circle radius and, subsequently, road width required depends on distance of tow hook to rear axle. To reduce the turning centre radius and road width, it is proposed to tow equipment with a towing trailer with rear wheels as steer wheels.

Figure 1 illustrates a configuration of the prior art where equipment (10) is towed by a vehicle / semi-trailer (12) with rear axle wheels in non-steered mode.

It was noticed that the achieved turning circle radius and road width, in this configuration of the prior art, was more than what was generally found in hilly areas with U bends and short turns. This issue needs to be solved.

Therefore, an intelligent system is required to synchronise movements, using pre defined parameters, of driver component and driven component; with the driver component leading the driven component. OBJECTS OF THE INVENTION:

An object of the invention is to synchronise movements of a driver component and a driven component.

Another object of the invention is to achieve turning circle radius equal to and less than towing vehicle alone. An object of the invention is to provide a system for synchronizing parameter dependent movement between a driver component and a driven component, said parameter being speed parameter. Another object of the invention is to provide a system for synchronizing parameter dependent movement between a driver component and a driven component, said parameter being turning radius parameter.

SUMMARY OF THE INVENTION: According to this invention, there is provided a system for synchronizing speed- dependent and tuming-radius-dependent movement between a driver component and a driven component, said system comprises:

- a steerable axle being provided on said driven component, with rear wheels of said driven component being coupled to said steerable axle; - a first speed sensor configured to sense speed of a front left wheel of a driven component;

- a second speed sensor configured to sense speed of a front right wheel of a driven component;

- a processor, with a traction controller, in order to determine steering angle for controlling angle of turning of each of said driven steerable rear wheels of said driven component in response to sensed speed and angle of turn of front operative inner wheel of said driven component and sensed speed and angle of turn of front operative outer wheel of said driven component, said processor, with said traction controller, being configured to compute difference in speed between said front operative outer wheel and said front operative inner wheel and providing a processed output, said processed output comprising a first angle (5i), being a first set point, for said steerable rear operative inner wheel of said driven component and a second angle (do), being a second set point, for said steerable rear operative outer wheel of said driven component, in that, said processor being configured to: o map difference between sensed speed and angle of said front operative inner wheel of said driven component and sensed speed and angle of said front operative outer wheel of said driven component with respect to turning circle diameter; o determine steering angle for said steerable rear operative inner wheel and said steerable rear operative outer wheel as a function of Ackerman steering condition; o obtain feedback signal of change in angle of each of said rear wheels, of said driven component, and corresponding change in speed in each of said front wheels, of said driven component; and o ensure closed loop signal and gain based on difference between determined steering angle, and obtained feedback signal in order to ensure steering, correlative to said steering angle (ST), in a defined range, thereby avoiding oversteering or under steering.

In at least an embodiment, said front operative inner wheel of said driven component is coupled with a first phonic wheel having a first proximity sensor for sensing teeth on said corresponding first phonic wheel, thereby detecting speed using a speed sensor.

In at least an embodiment, said front operative outer wheel of said driven component is coupled with a second phonic wheel having a second proximity sensor for sensing teeth on said corresponding second phonic wheel, thereby detecting speed using a speed spensor. In at least an embodiment, a first converter is configured to receive sensed speed from said front operative inner wheel of said driven component before passing on said sensed data to said traction controller.

In at least an embodiment, a second converter is configured to receive sensed speed from said front operative outer wheel of said driven component before passing on said sensed data to said traction controller. In at least an embodiment, an encoder, communicably coupled to said rear wheels, is configured to obtain said feedback signals.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:

Figure 1 illustrates a configuration of the prior art where equipment is towed by a vehicle / semi-trailer with rear axle wheels in non-steered mode.

The invention will now be described in relation to the accompanying drawings, in which: Figure 2 illustrates a configuration of a driver component (i.e. a vehicle / semi trailer) and a driven component (i.e. equipment) according to this current invention;

Figure 3 illustrates a control flow diagram of this invention; and Figure 4 illustrates relationship between the Steering Angle (ST) (on X axis) and the turning angles or set points of rear outer wheel and rear inner wheel (on Y axis) and set point angles calculated using three degree polynomial equations, considering TCD 20 Meters. DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS: According to this invention, there is provided a system for synchronizing speed- dependent and turning-radius-dependent movement between a driver component and a driven component.

To overcome issues of the prior art, a new configuration is proposed in which highly loaded axle is taken in front side and rear light axle with low loads is converted to steerable axle. In at least an embodiment, a steerable axle is provided on said driven component (20).

Figure 2 illustrates a configuration of a driver component (12) (i.e. a vehicle / semi-trailer) and a driven component (20) (i.e. equipment) according to this current invention.

In at least an embodiment, the rear wheels, of the driven component (20) are made steerable and are steered with an assembly of this invention.

The term, ‘steering angle’ (ST) is defined as an angle between a median of a driver component (12) and a median of a driven component (20).

Using the assembly of this invention, the rear wheels are steered with measuring included angle between towing vehicle and equipment (termed as Steering Angle or ST) to maintain instantaneous centre to fulfill Ackerman steering condition.

Figure 3 illustrates a control flow diagram of this invention. In at least an embodiment, a first speed sensor senses speed (in RPM) of a front operative inner wheel of a driven component (20). In at least an embodiment, a second speed sensor senses speed (in RPM) of a front operative outer wheel of a driven component (20). A processor computes difference in speed between the front operative inner wheel and the front operative outer wheel and provides an output.

As a driver component (12) (vehicle) with driven component (20) (trailer) turns towards left or right, the speed (rpm) between the front left (i.e. operative inner) wheel and the front right (i.e. operative outer) wheel changes. If vehicle turns right, the speed (rpm) of the front left (i.e. operative outer) wheel is more compared to the speed (rpm) of the front right (i.e. operative inner) wheel of the driven component (20) (trailer). If vehicle turns left, the speed (rpm) of the front left (i.e. operative inner) wheel is less compared to the speed (rpm) of the front right (i.e. operative outer) wheel of the driven component (20) (trailer).

Measuring pulse period method is used for measuring speed using low PPR sensors such as proximity sensors (21a, 21b) for sensing teeth on corresponding phonic wheels (22a, 22b), mounted on the front left and right wheel hubs, of the driven component (20), of the vehicle system. Width of teeth and space between teeth is equal. Preferably, positive fitment is done for phonic wheel (22a, 22b) and wheel hub to ensure no relative motion between phonic wheel (22a, 22b) and hub. Period is the time from the start of one pulse to the start of the next pulse.

Reference numeral 19 refers to rear wheel, with mounted / coupled encoder, of driven component (20). When vehicle (12, 20) moves straight, speed difference between front left wheel and front right wheel is zero. Output signals (25) of corresponding converters (24a, 24b) is fed to a traction controller (26) to control angle of driven component (20). Driven component’s angle for rear wheel turning is controlled by difference between analog signals (AO) of converters. In order to have same path of driver component (12) turning, driven component’s (20) rear wheel turning angle is controlled by mapping difference between analog signals (AO) of converters (24a, 24b) with respect to turning circle diameter (TCD). Using the Ackermanns steering principle, from the difference between AO, the steering angle (ST) (refer Figure 2) is ascertained. Once the steering angle (ST) is ascertained, the angle of turning of the rear wheels (i.e. dϊ and do) is taken from the lookup table given below. The steering motors on the steering columns of the trailers rear wheel are then activated in such a way that the rear wheels are turned by the required angle (i.e. dϊ and do).

Here, dϊ is the angle of turning of the inner wheel (refer Figure 2) and do is the angle of turning of the outer wheel (refer figure 2). In case of a right turn the right wheel is the inner wheel while the left wheel is the outer wheel. Similarly, during a left turn (which is shown in Figure 2), the left wheel is the inner wheel while the right wheel is the outer wheel.

When vehicle (12, 20) turns towards right or left, there is change in speed of front left wheel of driven component (20) with respect to front right wheel of driven component (20). Therefore, the output of converter (24a, 24b) changes proportional to change in speed. This converter output is fed to the traction controller (26). The traction controller (26) has been programmed to create a set point (turning angles do, dϊ) for driven component’s rear wheels. Set point (do, dϊ) calculation has been decided based on difference between analog signals of converters and TCD. Typically, a “set point” is created based on maintaining turning circle diameter (TCD) and also avoiding wheel dragging. According to a non-limiting exemplary embodiment, set point (do, dϊ) with respect to steering angles (ST) for TCD 20 m is as below.

The set points (do, dϊ), with respect to steering angle (ST), is defined as turn angle of rear wheel and this angle is calculated using three degree polynomial equations, considering TCD 20 Meters, as shown in Figure 4 of the accompanying drawings.

Once controller (26) gets input (25) from converters (24), the controller (26) sets desired set points based on look up table already available and configured in the controller (26). The traction controller (26) commands with signal (27) for controlling rear wheels through a hybrid control system (29) coupled with rear wheel (19). Feedback (33) is taken using encoders (19) mounted on each of the rear wheels. Hence, this architecture ensures closed loop and gain can be set as per system response, which ensures smooth torque control (30) to the rear wheels. The controller’s (26) output comprises steering angle (ST).

Two converters are used and difference of both outputs is fed to the traction controller (26).

In at least an embodiment, the processor, with the traction controller (26), is configured to determine steering angle (ST) for controlling angle of turning of each of said driven steerable rear wheels of said driven component (20) in response to sensed speed and angle of turn of front operative inner wheel of said driven component (20) and sensed speed and angle of turn of front operative outer wheel of said driven component (20), said processor, with said traction controller (26), is configured to compute difference in speed between said front operative outer wheel and said front operative inner wheel and providing a processed output, said processed output comprising a first angle (6i), being a first set point, for said steerable rear operative inner wheel of said driven component (20) and a second angle (do), being a second set point, for said steerable rear operative outer wheel of said driven component (20), in that, said processor being configured to: o map difference between sensed speed and angle of said front operative inner wheel of said driven component (20) and sensed speed and angle of said front operative outer wheel of said driven component (20) with respect to turning circle diameter (TCD); o determine steering angle (ST) for said steerable rear operative inner wheel and said steerable rear operative outer wheel as a function of Ackerman steering condition; o obtain feedback signal of change in angle of each of said rear wheels, of said driven component (20), and corresponding change in speed in each of said front wheels, of said driven component (20); and o ensure closed loop signal and gain based on difference between determined steering angle (ST), and obtained feedback signal in order to ensure steering, correlative to said steering angle (ST), in a defined range, thereby avoiding oversteering or under steering.

In order to have smooth rolling of wheel, both rear wheel angles are made to be different intentionally suggested by Ackerman steering phenomenon. The TECHNICAL ADVANCEMENT of this invention lies in providing a system for synchronizing speed-dependent and tuming-radius-dependent movement between a driver component and a driven component. The assembly of this invention assists in achieving turning circle radius equal to and less than towing vehicle alone. The road width required was drastically reduced than that required for prior art configurations. The assembly of this invention uses flexible strings for measurement and can be used in any terrain with side and ground slopes.

The above description of exemplary embodiments of the present invention is not intended to be exhaustive or to limit the embodiments of the invention to the precise forms disclosed above. Although specific embodiments and examples are described herein for illustrative purposes and to allow others skilled in the art to comprehend their teachings, various equivalent modifications may be made without departing from the spirit and scope of the disclosure, as will be recognized by those skilled in the relevant art.