FIELD OF THE INVENTION: This invention relates to the field of automobile engineering and mechanical engineering.

Particularly, this invention relates to a system for controlling movement of driven component based on movement of driver component.

BACKGROUND OF THE INVENTION:

In case of towing of equipment along long lengths of hilly areas, vehicles always face problems related to turning circle radius and road width because of U bends, short turns and narrow road widths. This results in a lot of to and fro motion of the vehicle, in order to negotiate those turns. This also results in frequent hooking, unhooking, and slow movement of equipment and vehicle; which, eventually, results in more time requirement for transport.

When any equipment is used as semi-trailer, it has a relatively bigger turning circle radius and, consequently, road width required depends on distance between tow hook and rear axle.

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. OBJECTS OF THE INVENTION:

An object of the invention is to reduce turning circle radius.

Another object of the invention is to provide an assembly for a vehicle (driver component) / trailer (driven component) in order for the vehicle (driver component) / trailer (driven component) to use its rear wheels as steer wheels.

Yet another object of the invention is to provide a system which incorporates computation / sensing of steering angle for rear wheels of a driven component to reduce overall road width and turning circle diameter.

Still another object of the invention is to provide a system which senses turning radius of a driver component in order to convert it into required turning radius for rear wheels of a corresponding driven component. SUMMARY OF THE INVENTION:

According to this invention, there is provided a system for controlling movement of driven component based on movement of driver 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; an ‘A’ frame configured to be coupled to a tow hook, said tow hook being coupled to said driver component, said A-frame being configured to be coupled to a driven component, said ‘A’ frame having multiple degrees of freedom with respect to said tow hook; draw wire sensors used to measure length between said driver component and an associated said driven component, in that, a first draw wire being coupled at its first-side end of a chassis of said driver component and being coupled at its second-side end to a first potentiometer located on an operative distal end of a first lateral member of said ‘A’ frame, and a second draw wire being coupled at its first- side end of a chassis of said driver component and being coupled at its second-side end to a second potentiometer located on an operative distal end of a second lateral member of said ‘A’ frame, said first potentiometer being configured to sense distance between said driver component and said driven component, said second potentiometer being configured to sense distance between said driver component; and a controller, in order to determine steering angle by controlling angle of turning of each of said driven steerable rear wheels, of said driven component, in response to sensed speed distance of between front operative inner wheel of said driver component and said driven component and sensed speed of front operative outer wheel of distance between said driver component and said driven component, said controller, being configured to compute difference in displacement between potentiometers and mapping said computed difference with respect to Turning Centre Distance of said vehicle in order to obtain a processed output, said processed output comprising a first angle (dϊ), 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 at least an embodiment, said ‘A’ frame comprises: a base; an eye on one side of the base; a middle shaft member / tube configured to move up and down, back and forth, and roll; - at least two lateral members extending from said base, on its other side in an

‘A’ shaped format, in that a first lateral members extending in an angularly displaced manner, in a first direction, with respect to a middle shaft member that also extends from said base and a second lateral member extending in an angularly displaced manner, in a second direction, with respect to said middle shaft member.

In at least an embodiment, a chassis end of said driver component comprises a tow hook to which said ‘A’ frame is attached.

In at least an embodiment, said controller is configured to: - receive sensed differential distance inputs from said first potentiometer and said second potentiometer each of said potentiometers being configured to provide corresponding outputs relating to corresponding changes in draw wire sensor lengths depending on turn angle and turn direction between said driver component and said driven component; - receive vehicle speed inputs; receiving instantaneous (feedback) steering wheel angle input; receiving reference steering wheel angle input; comparing received reference steering wheel angle input with said received instantaneous (feedback) steering wheel angle to obtain an angle difference output; and computing a control signal to determine said first angle (5i), being a first set point, for said steerable rear operative inner wheel of said driven component and said second angle (do), being a second set point, for said steerable rear operative outer wheel of said driven component, said first angle and said second angle being a function of said received angle and turn direction inputs, said vehicle speed inputs, and said angle difference output; in order to ensure steering, correlative to said steering angle, in a defined range, thereby avoiding oversteering or understeering.

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;

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

Figure 3 a schematic of the assembly of this invention; Figure 4 illustrates this assembly when the driver component is taking a right turn; Figure 5 illustrates this assembly when the driver component is taking a left turn; and

Figure 6 illustrates a flow diagram of a controller, used by this invention. DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS:

According to this invention, there is provided a system for controlling movement of driven component (20) based on movement of driver component (12). To overcome issues of the prior art, a new configuration is proposed in which highly loaded axle of the driven component (20) 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 / tractor) and a driven component (20) (i.e. equipment / trailer) 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 by measuring included angle, steering angle (ST), between driver component (12) and driven component (20) to maintain instantaneous centre to fulfill Ackerman steering geometry.

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) as shown in figure 2.

Figure 3 a schematic of the assembly of this invention.

In at least an embodiment, a draw wire sensor (22a, 22b) is used to measure length between a driver component (12) (i.e. a vehicle) and an associated driven component (20) (i.e. a trailer coupled to a vehicle). Draw wire sensors offer a simple solution to measure linear position. Utilizing a flexible cable, a spring- loaded spool, and a sensor (an optical encoder with incremental, absolute, analog or potentiometric output), draw wire sensors can precisely measure linear position. Draw wire sensors do not need precise linear guidance and are ideal for wet, dirty, or outdoor environments and applications where measuring range travels over harsh environments. A chassis end of the driver component (12) comprises a tow hook (14) to which an ‘A’ frame (16) is attached.

In at least an embodiment, the A’ frame comprises a base; an eye on one side of the base; a middle shaft member / tube configured to move up and down, back and forth, and roll; and at least two lateral members extending from said base, on its other side in an ‘A’ shaped format, in that a first lateral members extending in an angularly displaced manner, in a first direction, with respect to a middle shaft member that also extends from said base and a second lateral member extending in an angularly displaced manner, in a second direction, with respect to said middle shaft member.

In at least an embodiment, from a first-side end (24a) of the chassis of the driver component (12), a first draw wire (22a) is coupled at its one end and the other end of the first draw wire (22a) is coupled to a first potentiometer (30a) located on the first-side of the ‘A’ frame. The first potentiometer (30a) is configured to measure distance between the driver component (12) and the driven component (20) during a turning action. In at least an embodiment, from a second-side end (24b) of the chassis of the driver component (12), a second draw wire (22b) is coupled at its one end and the other end of the second draw wire (22b) is coupled to a second potentiometer (30b) located on the second-side of the ‘A’ frame. The second potentiometer (30b) is configured to measure distance between the driver component (12) and the driven component (20) during a turning action. Figure 4 illustrates this assembly when the driver component is taking a right turn. As the driver component (12) with driven component (20) turns one way, the distance between rear end of driver component (12) and front end of the driven component (20) changes i.e if driver component (12) turns in (right) (Refer Figure 4), the driven component’s (20) right hand side comes closer to the driver component’s (12) chassis and same change in length is added to left side draw by wire sensor (22a, 30a) of the driven component (20). These changes in distance are measured by the first potentiometer (30a) and the second potentiometer (30b) and used by a controller.

Figure 5 illustrates this assembly when the driver component is taking a left turn. As a driver component (12) with driven component (20) turns the other way, the distance between rear end of driver component (12) and the front end of the driven component (20) changes i.e if driver component (12) turns out (left) (Refer Figure 5), the driven component’s (20) left hand side comes closer to the driver component’s (12) chassis and same change in length is added to right side draw by wire sensor (22b, 30b) of the driven component (20). These changes in distance are measured by the first potentiometer (30a) and the second potentiometer (30b) and used by a controller.

When driver component (12) moves straight, the driven component’s distance between right hand draw wire (22b) and left hand draw wire (22a) is same. Output of draw wire sensor is used to control rear wheel axle angle of the driven component (20). The driven component’s (20) rear angle wheel turning is controlled by the potentiometers (30a, 30b). In order to have same path of turning as that of the driver component (12), the driven component’s (20) rear wheel angle (turning angles dϊ & do) is controlled by mapping potentiometers (30a, 30b) output with respect to Turning Center Distance (TCD). 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. Figure 6 illustrates a flow diagram of a controller, used by this invention, which receives inputs from the potentiometers (30a, 30b) and use these inputs to control rear wheel axle angle of the driven component (20).

When there is change in draw wire sensor length, its output changes proportional to change in length. This output (differential distance) is fed to the controller (50); the embedded controller has been programmed to create set point (turning angles do, dϊ) for driven component’s (20) rear wheels. Set point calculation has been decided based on draw wire length and TCD. Set point is created based on maintaining Turning Center Distance (TCD) and also avoiding wheel dragging. The controller’s (50) output comprises steering angle (ST).

Once controller (50) gets input from draw wires and potentiometers (22a, 30a, 22b, 30b), the controller sets desired set point (turning angles do, dϊ) based on look up table (Table 1), controller gives signal for turning rear wheels and feedback is taken using encoder mounted on rear wheel. Hence, this architecture ensures closed loop and gain are set as per system response which ensures smooth torque control.

Table 1

The controller comprises an ‘angle and angular velocity loop controller’ (50a) which receives vehicle speed input (51) and angle difference output (53) from a comparator (52) which compares reference steering wheel angle input (57) with a sensed feedback steering wheel angle (58), a ‘torque loop controller’ (50b) which receives vehicle speed input (51), a ‘main loop controller’ (50c) which receives inputs from the ‘angle and angular velocity loop controller’ (50a) as well as from the ‘torque loop controller’ (50b); in order to output a control signal (54) to be given to a motor drive (55a) and steering wheel motor (55b). The angle of the steering wheel is sensed by a sensor (56) and given as feedback (58) to the comparator (52).

Two draw wire sensors/ potentiometers (22a, 30a, 22b, 30b), are used and difference of both outputs are taken into system. This helps the control to differentiate the turning direction i.e. IN/Right or OUT/Left movement of driven component (20).

In order to have smooth rolling of wheel, both rear wheel angles are made to be different intentionally as suggested by Ackerman phenomenon.

The TECHNICAL ADVANCEMENT of this invention lies in providing an assembly for controlling movement of driven component based on movement of driver component. With the use of this invention’s configuration, the inventors have achieved a turning circle radius equal to and less than towing vehicle alone. The road width required was drastically reduced than earlier configuration. This configuration, due to use of flexible strings for measurement, 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.