Electrical power steering control using system state predictions

• US 10,562,561 B2
• Filed: 04/25/2017
• Issued: 02/18/2020
• Est. Priority Date: 04/25/2016
• Status: Active Grant

• Current Assignee: Steering Solutions IP Holding Corporation (Nexteer Automotive Group Ltd.)
• Original Assignee: Steering Solutions IP Holding Corporation (Nexteer Automotive Group Ltd.)
• Inventors: Wang, Qi, Zhang, Xingye, Varunjikar, Tejas M., Champagne, Anthony J.
• Primary Examiner(s): Weber, Tamara L
• Application Number:
  US15/496,481
• Publication Number:
  US 20170305458A1
• Time in Patent Office: 1,029 Days
• Field of Search: None
• CPC Class Codes: B60W 50/00 Details of control systems for road vehicle drive control not related to the control of a particular sub-unit , e.g. process diagnostic or vehicle driver interfaces
• CPC Class Codes: B62D 5/0463 calculating assisting torque from the motor based on driver input
• CPC Class Codes: B62D 6/001 the torque NOT being among the input parameters

Abstract

An embodiment of a method of controlling one or more components of a vehicle includes receiving a reference steering command and one or more measurement signals related to a steering system of a vehicle, and estimating, by a processing device, a state of the steering system based on the one or more measurement signals, the steering system including at least a handwheel and a steering motor. The method also includes determining a maximum state achievable by the steering system at one or more times subsequent to receiving the one or more measurement signals, and controlling, by a control module, the steering system based on the steering reference command and the maximum state.

Claims

1. A method of controlling one or more components of a vehicle, comprising:

receiving a reference steering command and one or more measurement signals related to a steering system;

forecasting, by a processing device, a future state of the steering system, at at least one future time subsequent to a time of the receiving the one or more measurement signals, based on the one or more measurement signals, the future state being calculated using an estimated rack force and a mass model of the steering system, and the rack force being calculated using a rack force model; and

controlling, by a control module, the steering system based on the steering reference command and the future state.

2. The method of claim 1, wherein the future state of the steering system comprises a maximum state achievable by the steering system at the at least one future time.

3. The method of claim 2, wherein controlling includes limiting a command generated by a steering control system based on the maximum state.

4. The method of claim 2, wherein the steering system comprises at least a handwheel, and the maximum state comprises a maximum achievable handwheel position.

5. The method of claim 2, wherein the steering system comprises at least a steering motor, and the maximum state comprises a maximum achievable motor torque of the steering motor.

6. The method of claim 1, wherein the one or more measurement signals include at least one of a motor position and a motor velocity.

7. The method of claim 1, wherein the rack force model includes a bicycle model and a static tire model, and the rack force is a blended rack force which is a blend of a rolling rack force estimated based on the bicycle model and a static rack force estimated based on the static tire model.

8. The method of claim 1, wherein the rack force is estimated based on a state observer in combination with a mass model of the system.

9. The method of claim 8, wherein the mass model is a one-mass model.

10. The method of claim 1, wherein the forecasting the future state comprises iteratively estimating the future state for each of one or more successive time steps, based on a set of differential equations derived from the mass model.

11. The method of claim 1, further comprising receiving a motor torque command, estimating a motor torque envelope based on motor parameters including voltage and thermal limits of the motor, and limiting the motor torque command based on the motor torque envelope.

12. A control system, comprising:

a processing device configured to;

receive a reference steering command and one or more measurement signals related to a steering system,

forecast a future state of the steering system, at at least one future time subsequent to a time of the receiving the one or more measurement signals, based on the one or more measurement signals; and

a control module configured to control the steering system based on the steering reference command and the future state; and

wherein the processing device is configured to calculate the future state based on an estimated rack force and a mass model of the steering system, the estimated rack force being calculated using a rack force model.

13. The system of claim 12, wherein the future state of the steering system comprises a maximum state achievable by the steering system at the at least one future time.

14. The system of claim 13, wherein the control module is configured to

limit a command generated by a steering control system based on the maximum state.

15. The system of claim 13, wherein the steering system comprises at least a handwheel, and the maximum state comprises a maximum achievable handwheel position.

16. The system of claim 13, wherein the steering system comprises at least a steering motor, and the maximum state comprises a maximum achievable motor torque of the steering motor.

17. The system of claim 12, wherein the one or more measurement signals include at least one of a motor position and a motor velocity.

18. The system of claim 12, wherein:

the rack force model includes a bicycle model and a static tire model,

the rack force is a blended rack force which is a blend of a rolling rack force estimated based on the bicycle model and a static rack force estimated based on the static tire model.

19. The system of claim 12, wherein the rack force is estimated based on a state observer in combination with a mass model of the system.

20. The system of claim 19, wherein the mass model is a one-mass model.

21. The system of claim 12, wherein the processing device is configured forecast the future state by iteratively estimating the future state for each of one or more successive time steps, based on a set of differential equations derived from the mass model.

22. The system of claim 12, wherein the processing device is further configured to receive a motor torque command, estimate a motor torque envelope based on motor parameters including voltage and thermal limits of the motor, and limit the motor torque command based on the motor torque envelope.