Method of controlling a differential motor torque steering system of a working machine and system thereof

Patent metadata

Field	Value
Publication number	US-11317556-B2
Application number	US-202017011078-A
Country	US
Kind code	B2
Filing date	Sep 3, 2020
Priority date	Sep 3, 2020
Publication date	May 3, 2022
Grant date	May 3, 2022

Abstract

A steering system for controlling an agricultural machine having a pair of front and rear wheels includes a controller and a steer input sensor for detecting a change in an operator steer input corresponding to a steer command. The system includes a displacement input for communicating a motor displacement associated with an operating mode. A primary differential steering system includes a drive motor for operably controlling the pair of front wheels and a secondary steering system controls the pair of rear wheels. The controller determines if the motor displacement is being controlled according to a first motor displacement or a second motor displacement, and outputs a control signal to actuate first and second actuators as a function of the steer command. The control signal includes a rear steering gain that is a function of machine speed and either the first motor displacement or the second motor displacement.

First claim

The invention claimed is:

1. A steering system for controlling an agricultural machine having a front traction mechanism and a pair of rear wheels, comprising:
a controller;
a steer input sensor in communication with a steer input and the controller, the steer input sensor configured to detect a change in the steer input corresponding to a steer command;
a displacement input in communication with the controller for communicating a first motor displacement associated with a first operating mode and a second motor displacement associated with a second operating mode;
a speed sensor for detecting a machine speed, the speed sensor disposed in communication with the controller;
a primary differential steering system including a drive motor for operably controlling the front traction mechanism, the drive motor being selectively operable according to the first motor displacement and the second motor displacement; and
a secondary steering system for operably controlling the pair of rear wheels, the secondary steering system comprising a first actuator for controlling a first rear wheel of the pair of rear wheels and a second actuator for controlling a second rear wheel of the pair of rear wheels;
wherein, the controller determines if the motor displacement is being controlled according to the first motor displacement or the second motor displacement;
further wherein, the controller outputs a control signal to operably actuate the first and second actuators as a function of the steer command, wherein the control signal comprises a rear steering gain that is a function of machine speed and either the first motor displacement or the second motor displacement.

2. The steering system of claim 1 , wherein the controller outputs a second control signal to operably control the primary differential steering system based on the steer command.

3. The steering system of claim 2 , wherein the primary differential steering system comprises:
the front traction mechanism comprises a first front wheel and a second front wheel;
a first pump and a first motor for operably controlling the first front wheel of the pair of front wheels;
a second pump and a second motor for operably controlling the second front wheel of the pair of front wheels; and
a mechanical mechanism for varying a displacement of the first and second pumps based on the second control signal.

4. The steering system of claim 2 , wherein the primary differential steering system comprises:
the traction mechanism comprises a first front wheel and a second front wheel;
a first pump and a first motor for operably controlling the first front wheel of the pair of front wheels; and
a second pump and a second motor for operably controlling the second front wheel of the pair of front wheels;
wherein, the controller determines a gain for an electronic swash plate control for each of the first and second pumps;
further wherein, the second control signal comprises a first portion of flow to the first motor and a second portion of flow to the second motor as a function of the gain.

5. The steering system of claim 1 , wherein the first and second actuators are operably controlled independently from one another.

6. The steering system of claim 1 , wherein the rear steering gain comprises a first linear steering gain profile and a second linear steering gain profile, the first linear steering gain profile associated with the first motor displacement and the second linear steering gain profile associated with the second motor displacement.

7. The steering system of claim 6 , wherein:
a slope of the first linear steering gain profile decreases as machine speed increases; and
a slope of the second linear steering gain profile increases as machine speed increases.

8. The steering system of claim 1 , wherein the rear steering gain comprises a first non-linear steering gain profile and a second non-linear steering gain profile, the first non-linear steering gain profile associated with the first motor displacement and the second non-linear steering gain profile associated with the second motor displacement.

9. The steering system of claim 8 , wherein:
the rear steering gain decreases as machine speed increases according to the first non-linear steering gain profile; and
the rear steering gain increases as machine speed increases according to the second non-linear steering gain profile.

10. The steering system of claim 8 , wherein the controller outputs a second control signal to operably control the primary differential steering system based on the steer command, the second control signal comprising a front steering gain that is a function of machine speed and either the first motor displacement or the second motor displacement;
further wherein, the front steering gain comprises a third non-linear steering gain profile and a fourth non-linear steering gain profile, the third non-linear steering gain profile associated with the first motor displacement and the fourth non-linear steering gain profile associated with the second motor displacement.

11. The steering system of claim 10 , wherein, at any given machine speed, a slope of the first non-linear steering gain profile is approximately the same as a slope of the third non-linear steering gain profile, and a slope of the second non-linear steering gain profile is approximately the same as a slope of the fourth non-linear steering gain profile.

12. The steering system of claim 1 , wherein the rear steering gain comprises a non-linear steering gain profile having a first portion and a second portion, the first portion associated with the first motor displacement and the second portion associated with the second motor displacement.

13. The steering system of claim 12 , wherein the controller operably adjusts the rear steering gain between the first portion and the second portion at a pre-defined machine speed.

14. The steering gain of claim 12 , wherein:
the rear steering gain decreases as machine speed increases according to the first portion of the non-linear steering gain profile; and
the rear steering gain increases as machine speed increases according to the second portion of the non-linear steering gain profile.

15. A steering system for controlling an agricultural machine having a front traction mechanism and a pair of rear wheels, comprising:
a controller configured to output a steer command;
a displacement input in communication with the controller for communicating a first motor displacement associated with a first operating mode and a second motor displacement associated with a second operating mode;
a speed sensor for detecting a machine speed, the speed sensor disposed in communication with the controller;
a primary differential steering system including a drive motor for operably controlling the front traction mechanism, the drive motor being selectively operable according to the first motor displacement and the second motor displacement; and
a secondary steering system for operably controlling the pair of rear wheels, the secondary steering system comprising a first actuator for controlling a first rear wheel of the pair of rear wheels and a second actuator for controlling a second rear wheel of the pair of rear wheels;
wherein, the controller determines if the motor displacement is being controlled according to the first motor displacement or the second motor displacement;
wherein, the controller outputs a first control signal to operably actuate the first and second actuators as a function of the steer command, wherein the control signal comprises a rear steering gain that is selected from a first s

Assignees

• Deere & Co

Inventors

• Karst Austin J
• Wanner Jason J

Classifications

• A01B69/006

  derived from the steering of the tractor · CPC title

• B62D11/24

  Endless track steering specially adapted for vehicles having both steerable wheels and endless track · CPC title

• A01B69/007 Primary

  Steering or guiding of agricultural vehicles, e.g. steering of the tractor to keep the plough in the furrow · CPC title

• B62D6/00

  Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits (means for initiating a change in direction B62D1/00; steering valves B62D5/06; combined with means for inclining the vehicle body or wheels on bends B62D9/00) · CPC title

• B62D5/06

  fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle · CPC title