WORK VEHICLE WITH ENHANCED IMPLEMENT POSITION CONTROL AND BI-DIRECTIONAL SELF-LEVELING FUNCTIONALITY

• US 20160153165A1
• Filed: 12/02/2014
• Published: 06/02/2016
• Est. Priority Date: 12/02/2014
• Status: Active Grant

• Current Assignee: Blue Leaf IP Incorporated (CNH Industrial N.V.)
• Original Assignee: CNH Industrial America LLC (CNH Industrial N.V.)
• Inventors: Singh, Aditya, Wu, Duqiang, Gulati, Navneet
• Granted Patent: US 9,822,507 B2
• Time in Patent Office: Days
• CPC Class Codes: E02F 3/433 horizontal, e.g. self-levelling
• CPC Class Codes: E02F 9/2029 Controlling the position of implements in function of its load, e.g. modifying the attitude of implements in accordance to vehicle speed control for hydraulic or pneumatic drives E02F9/2203, E02F9/2221 and E02F9/2253 take precedence

Abstract

A method for automatically adjusting the position of an implement of a lift assembly may generally include receiving a signal indicative of a position and/or a movement parameter of loader arms of the lift assembly and receiving a signal indicative of a pressure of a hydraulic fluid supplied within the lift assembly. The method may also include calculating a first correction signal associated with adjusting the position of the implement, wherein the correction signal is calculated by inputting the position and/or the movement parameter and the fluid pressure into a control equation based on a model of the operational dynamics of the lift assembly. In addition, the method may include generating a valve command signal based at least in part on the correction signal and transmitting the valve command signal to a valve for maintaining the implement at a fixed orientation relative as the loader arms are being moved.

Claims

1. A method for automatically adjusting the position of an implement of a lift assembly for a work vehicle, the lift assembly comprising a pair of loader arms coupled to the implement, the method comprising:

receiving, with a computing device, a signal indicative of at least one of a position or a movement parameter of the loader arms as the loader arms are being moved;

receiving, with the computing device, a signal indicative of a fluid pressure of a hydraulic fluid supplied within the lift assembly;

accessing, with the computing device, a control equation that is based at least partially on a model of operational dynamics associated with the lift assembly when moving the loader arms;

calculating, with the computing device, a first correction signal associated with adjusting the position of the implement, the first correction signal being calculated at least partially by inputting the at least one of the position or the movement parameter and the fluid pressure into the control equation;

generating, with the computing device, a valve command signal based at least in part on the first correction signal; and

transmitting, with the computing device, the valve command signal to a valve associated with the implement in order to maintain the implement at a fixed orientation relative to a given reference point as the loader arms are being moved.

2. The method of claim 1, wherein the movement parameter comprises at least one of a velocity, an acceleration or a rate of change of the acceleration.

3. The method of claim 1, wherein the fluid pressure corresponds to at least one of a rod-end pressure, a cap-end pressure, a source pressure or a tank pressure associated with the hydraulic fluid supplied to a hydraulic cylinder of the lift assembly.

4. The method of claim 1, further comprising receiving, with the computing device, a signal indicative of a fluid temperature of the hydraulic fluid.

5. The method of claim 4, wherein the first correction signal is calculated at least partially by inputting the at least one of the position or the movement parameter, the fluid pressure and the fluid temperature into the control equation.

6. The method of claim 1, further comprising:

receiving, with the computing device, a signal indicative of at least one of a position or a movement parameter of the implement as the loader arms are being moved;

comparing, with the computing device, the at least one of the position or the movement parameter for the implement to at least one of a desired position or a desired movement parameter for the implement;

calculating, with the computing device, an error signal based at least in part on the difference between the at least one of the position or the movement parameter for the implement and the least one of the desired position or the desired movement parameter for the implement; and

calculating, with the computing device, a second correction signal associated with adjusting the position of the implement based at least in part on the error signal.

7. The method of claim 6, further comprising calculating a model-based correction signal associated with adjusting the position of the implement based at least in part on the first and second correction signals.

8. The method of claim 7, wherein generating the valve command signal comprises generating the valve command signal based at least in part on the model-based correction signal.

9. The method of claim 1, further comprising:

receiving, with the computing device, a signal indicative of at least one of a position or a movement parameter of the implement as the loader arms are being moved;

comparing, with the computing device, the at least one of the position or the movement parameter for the implement to at least one of a desired position or a desired movement parameter for the implement;

calculating, with the computing device, an error signal based at least in part on the difference between the at least one of the position or the movement parameter for the implement and the least one of the desired position or the desired movement parameter for the implement; and

calculating, with the computing device, a forcing correction signal by inputting the error signal into a forcing function, the forcing function being associated with driving the error signal to zero.

10. The method of claim 9, wherein the forcing function corresponds to a sign function or a saturation function.

11. The method of claim 9, further comprising:

receiving, with the computing device, an indication of a fluid temperature of the hydraulic fluid;

determining, with the computing device, a control gain based at least in part on the fluid temperature; and

modifying, with the computing device, the forcing correction signal based on the control gain to generate a modified forcing correction signal.

12. The method of claim 11, wherein generating the valve command signal comprises generating the valve command signal based at least in part on the first correction signal and the modified forcing correction signal.

13. The method of claim 11, wherein the control equation corresponds to a sliding mode control algorithm.

14. A method for automatically adjusting the position of an implement of a lift assembly for a work vehicle, the lift assembly comprising a pair of loader arms coupled to the implement, the method comprising:

receiving, with a computing device, a signal indicative of at least one of a position or a movement parameter of the loader arms and the implement as the loader arms are being moved;

calculating, with the computing device, an error signal based at least in part on the difference between the at least one of the position or the movement parameter for the implement and at least one of a desired position or a desired movement parameter for the implement; and

receiving, with the computing device, a signal indicative of a fluid pressure of a hydraulic fluid supplied within the lift assembly;

accessing, with the computing device, a control equation that is based at least partially on a model of operational dynamics associated with the lift assembly when moving the loader arms, the control equation corresponding to a sliding mode control algorithm;

generating, with the computing device, a model-based correction signal associated with adjusting the position of the implement, the model-based correction signal being generated at least partially by inputting the at least one of the position or the movement parameter for the loader arms, the fluid pressure and the error signal into the control equation;

generating, with the computing device, a valve command signal based at least in part on the model-based correction signal; and

transmitting, with the computing device, the valve command signal to a valve associated with the implement in order to maintain the implement at a fixed orientation relative to a given reference point as the loader arms are being moved.

15. The method of claim 14, further comprising calculating, with the computing device, a forcing correction signal by inputting the error signal into a forcing function, the forcing function being associated with driving the error signal to zero.

16. The method of claim 15, wherein the forcing function corresponds to a sign function or a saturation function.

17. The method of claim 15, further comprising:

receiving, with the computing device, a signal indicative of a fluid temperature of the hydraulic fluid;

determining, with the computing device, a control gain based at least in part on the fluid temperature; and

modifying, with the computing device, the forcing correction signal based on the control gain to generate a modified forcing correction signal.

18. The method of claim 15, wherein generating the valve command signal comprises generating the valve command signal based at least in part on the model-based correction signal and the modified forcing correction signal.

19. The method of claim 14, further comprising receiving, with the computing device, a signal indicative of a fluid temperature of the hydraulic fluid, wherein the model-based correction signal is calculated at least partially by inputting the at least one of the position or the movement parameter for the loader arms, the fluid pressure, the error signal and the fluid temperature into the control equation.

20. A method for automatically adjusting the position of an implement of a lift assembly for a work vehicle, the lift assembly comprising a pair of loader arms coupled to the implement, the method comprising:

receiving, with a computing device, a signal indicative at least one of a position or a movement parameter of the loader arms as the loader arms are being moved;

receiving, with the computing device, a signal indicative of a fluid pressure of a hydraulic fluid supplied within the lift assembly;

generating, with the computing device, a valve command signal based at least in part on the fluid pressure and the at least one of the position or the movement parameter; and

transmitting, with the computing device, the valve command signal to a valve associated with the implement in order to maintain the implement at a fixed orientation relative to a given reference point as the loader arms are being moved.