Guidance and control of vehicle travel path and components

1. A system including a vehicle comprising a chassis having a forward and a rearward end, a traction drive comprising at least two drive wheels operatively mounted to the chassis for causing propulsion of the vehicle, a steering assembly for facilitating steering of the drive wheels when in an operating mode; a leading vehicle connected to the vehicle by a coupling assembly; a force sensor for sensing a force applied at the coupling assembly between the vehicle and the leading vehicle, and a controller; wherein in response to a displacement error of the vehicle relative to an intended travel path, the drive wheels and steering assembly are responsive to one or more control signals generated in accordance with the force sensed by the force sensor and the displacement error to substantially correct the displacement error of the vehicle relative to the intended travel path, wherein the displacement error of the vehicle is determined by the controller calculating a distance of a current position of the vehicle relative to a stored position representative of the intended travel path, wherein the intended travel path is stored in a data store associated with the controller.

2. The system according to claim 1 , comprising hydraulic motors, each motor being associated with a respective drive wheel for driving thereof to substantially correct the displacement error of the vehicle relative to the intended travel path, wherein the hydraulic motors are torque controlled to provide substantially the same torque to each hydraulic motor.

3. The system according to claim 1 , wherein the steering assembly comprises a linkage arrangement operatively interconnecting the drive wheels and a steering actuator, wherein the steering actuator is responsive to the one or more control signals to substantially correct the displacement error of the vehicle relative to the intended travel path.

4. The system according to claim 1 , further including a tool carriage assembly operatively mounted to the chassis and comprising a support section adapted to have mounted thereto a tool unit having a tool head, and an actuator; wherein in response to the displacement error of the tool head relative to the intended travel path, the actuator is responsive the one or more control signals to substantially correct the displacement error of the tool head relative to the intended travel path.

5. The system according to claim 4 , wherein the tool carriage assembly comprises:

a base section connectable to the chassis of the vehicle, wherein the support section comprises side members and cross members operatively connected together so as to provide for a pivot connection between adjacent ends of the members, the support section being pivotally mounted to the base section at pivot points intermediate the ends of opposed side members so that the side members are rotatable relative to the base section; wherein in response to the displacement error of the tool head relative to the intended travel path, the actuator is responsive to the one or more control signals to rotate the side members about the pivot points relative to the chassis to substantially correct the displacement error of the tool head relative to the intended travel path; wherein the controller is configured to determine the displacement error of the tool head by calculating a distance of a current position of the tool head relative to the stored position representative of the intended travel path.

6. The system according to claim 5 , wherein rotation of the side members about the pivot points cause a rotational movement of the tool unit about a pivot axis so that the tool head is displaced relative to the intended travel path.

7. The system according to claim 5 , wherein said support section is a parallelogram-type linkage.

8. The system according to claim 5 , wherein the vehicle is a seeding apparatus, wherein the tool unit is a seeder unit comprising a seed deposition outlet, wherein as a result of the rotation of the side members of the support section about the pivot points and relative to the chassis, the seed deposition outlet is displaced relative to the intended travel path to substantially correct seed deposition.

9. The system according to claim 1 , wherein the coupling assembly is a coupling hitch for attachment to the leading vehicle, wherein the coupling hitch includes the force sensor to sense the force applied to the coupling hitch.

10. The system according to claim 1 , wherein the drive wheels are responsive to the one or more control signals such that the propulsion of the vehicle is distributed between the drive wheels and the leading vehicle.

11. The system according to claim 1 , wherein the displacement error of the vehicle includes a linear displacement error of the vehicle relative to the intended travel path and an angular displacement error relative to the intended travel path.

12. A system according to claim 11 , wherein the controller is in communication with one or more further sensors, wherein one or more signals received from the one or more further sensors are indicative of: the current position of the vehicle; a current orientation of the vehicle; and a current offset position of the tool head; wherein the controller is configured to: calculate, based on the current position of the vehicle and the current orientation of the vehicle, the linear displacement error of the vehicle; and calculate, based on the current orientation of the vehicle, the angular displacement error of the vehicle.

13. The system according to claim 11 , wherein the controller is in communication with one or more further sensors, wherein one or more signals received from the one or more further sensors are indicative of: a current position of the leading vehicle; a current orientation of the leading vehicle; a current angular displacement between the leading vehicle and the vehicle; and wherein the controller is configured to: calculate, based on the current position of the leading vehicle and the current orientation of the leading vehicle, the current position of the vehicle; calculate, based on the current angular displacement and the current orientation of the leading vehicle, a current orientation of the vehicle; calculate, based on the current position of the vehicle and the current orientation of the vehicle, the linear displacement error of the vehicle; and calculate, based on the current orientation of the vehicle, the angular displacement error of the vehicle.

14. The system according to claim 1 , wherein the controller is configured to: receive a force signal from the force sensor; and generate at least some of the one or more controls signals to control the drive wheels based on a comparison of the force sensed as indicated by the force signal against one or more force thresholds.

15. The system according to claim 14 , wherein the one or more force threshold values include a first force threshold and a second force threshold, wherein the controller is configured to generate at least some of the one or more control signals to: increase a drive force of the drive wheels if the sensed force is greater than or equal to the first force threshold; or decrease the drive force of the drive wheels if the sensed force is less than the second force threshold.

16. A system including:

a vehicle comprising a chassis having a forward and a rearward end, a traction drive comprising at least two drive wheels operatively mounted to the chassis for causing propulsion of the vehicle, a steering assembly for facilitating steering of the drive wheels when in an operating mode, and a tool carriage assembly being operatively mounted on the vehicle chassis, the tool carriage assembly comprising a support section adapted to have mounted thereto a tool unit comprising a tool head; a leading vehicle connected to the vehicle by a coupling assembly; a force sensor for sensing a force applied at the coupling assembly between the vehicle and the leading vehicle; and

a control system including a controller and one or more further sensors in communication with the controller, the controller being associated with a data store, wherein the controller is configured to:

receive one or more signals from the one or more further sensors;

determine, based on the one or more signals and the stored position in the data store representative of the intended travel path, the displacement error of the vehicle relative to the intended travel path;

determine, based on the one or more signals and the stored position in the data store representative of the intended travel path, the displacement error of the tool head relative to the intended travel path; and

generate one or more control signals according to the displacement error of the vehicle relative to the intended travel path and the displacement error of the tool head relative to the intended travel path;

wherein the drive wheels and steering assembly are responsive to the one or more control signals generated in accordance with the force sensed by the force sensor and the displacement error of the vehicle relative to the intended travel path to substantially correct the displacement error of the vehicle relative to the intended travel path; and

wherein the support section is responsive to the one or more control signals to move relative to the vehicle chassis to substantially correct the displacement error of the tool head relative to the intended travel path.

17. The system according to claim 16 , wherein the displacement error of the vehicle includes a linear displacement error of the vehicle relative to the intended travel path and an angular displacement error of the vehicle relative to the intended travel path, and the displacement error of the tool head includes a linear displacement error of the tool head relative to the intended travel path.

18. The system according to claim 17 , wherein one or more signals received from the one or more further sensors are indicative of:

a current position of the vehicle;

a current orientation of the vehicle; and

a current offset position of the tool head;

wherein the controller is configured to:

calculate, based on the current position of the vehicle, the current orientation of the vehicle, and the current offset position of the tool head, a position of the tool head;

calculate, based on the current position of the vehicle and the current orientation of the vehicle, the linear displacement error of the vehicle;

calculate, based on the current orientation of the vehicle, the angular displacement error of the vehicle; and

calculate, based on the current position of the tool head, the linear displacement error of the tool head.

19. The system according to claim 17 , wherein the one or more signals received from the one or more further sensors are indicative of:

a current position of the leading vehicle;

a current orientation of the leading vehicle;

a current angular displacement between the leading vehicle and the vehicle; and

a current offset position of the tool head

wherein the controller is configured to:

calculate, based on the current position of the leading vehicle and the current orientation of the leading vehicle, a current position of the vehicle;

calculate, based on the current angular displacement and the current orientation of the leading vehicle, a current orientation of the vehicle;

calculate, based on the current position of the vehicle, the current orientation of the vehicle, and the current offset position of the tool head, a current position of the tool head;

calculate, based on the current position of the vehicle and the current orientation of the vehicle, the linear displacement error of the vehicle;

calculate, based on the current orientation of the vehicle, the angular displacement error of the vehicle; and

calculate, based on the current position of the tool head, the linear displacement error of the tool head.

20. The system according to claim 16 , wherein the controller is configured to:

receive a force signal from the force sensor; and

generate at least some of the one or more controls signals to control the drive wheels based on a comparison of the force sensed indicated by the force signal against one or more force thresholds.

21. The system according to claim 20 , wherein the one or more force threshold values include a first force threshold and a second force threshold, wherein the controller is configured to generate at least some of the one or more control signals to:

increase a drive force of the drive wheels if the sensed force is greater than or equal to the first force threshold; or

decrease the drive force of the drive wheels if the sensed force is less than the second force threshold.

22. The system according to claim 16 , wherein the vehicle includes a valve block having a plurality of valves which are in fluid communication with a fluid reservoir, wherein the valve block includes an electrical interface which receives the one or more control signals generated by the controller and actuates at least some of the one or more valves to hydraulically control at least one of the drive wheels, the steering assembly, and the relative movement of the support section.

23. The system according to claim 16 , wherein the support section being adapted to have mounted thereto a plurality of tool units, wherein movement of the support section relative to the chassis causes simultaneous displacement of the tool head of each tool unit relative to the intended travel path.

24. The system according to claim 16 , wherein the vehicle is a seeding apparatus, wherein the tool unit is a seeder unit comprising a seed deposition outlet, wherein as a result of the relative movement between the support section and the main body of the seeding apparatus, the seed deposition outlet is displaced relative to the intended travel path to substantially correct seed deposition.

25. The system according to claim 16 , wherein:

the drive wheels and steering assembly are responsive to the one or more control signals to cause a first lateral position adjustment of the vehicle relative to the intended travel path;

the support section is responsive to the one or more control signals to cause a second lateral position adjustment of the tool head relative to the vehicle chassis; and

the first lateral position adjustment is supplementary to the second lateral position adjustment.