ELECTRICAL POWER STEERING CONTROL USING SYSTEM STATE PREDICTIONS

• US 20170305458A1
• Filed: 04/25/2017
• Published: 10/26/2017
• 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.
• Granted Patent: US 10,562,561 B2
• Time in Patent Office: Days
• 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 of a vehicle;

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;

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.

2. The method of claim 1, wherein controlling includes limiting a command generated by a steering control system based on the maximum state.

3. The method of claim 1, wherein the state of the steering system is a handwheel position, and the maximum state includes a maximum achievable handwheel position.

4. The method of claim 1, wherein the state of the steering system is a motor torque generated by the steering motor, and the maximum state includes a maximum achievable motor torque.

5. The method of claim 1, wherein the one or more measurement signals include at least one of a motor position and a motor velocity, and estimating the state includes calculating a rack force based on a rack force model and calculating the system state based on the estimated rack force and a mass model of the steering system.

6. The method of claim 5, wherein the rack force model includes a bicycle model and a static tire model, and calculating the rack force includes estimating a rolling rack force based on the bicycle model and a static rack force based on the static tire model, and blending the static rack force and the rolling rack force based on vehicle speed to generate a blended rack force.

7. The method of claim 5, wherein the rack force is estimated based on a state observer in combination with a mass model of the system.

8. The method of claim 7, wherein the mass model is a one-mass model.

9. The method of claim 5, wherein determining the maximum state includes iteratively estimating the state for each of one or more successive time steps, based on a set of differential equations derived from the mass model.

10. 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.

11. 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 of a vehicle, estimate 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, and determine a maximum state achievable by the steering system at one or more times subsequent to receiving the one or more measurement signals; and

a control module configured to control the steering system based on the steering reference command and the maximum state.

12. The system of claim 11, wherein the control module is configured to limit a command generated by a steering control system based on the maximum state.

13. The system of claim 11, wherein the state of the steering system is a handwheel position, and the maximum state includes a maximum achievable handwheel position.

14. The system of claim 11, wherein the state of the steering system is a motor torque generated by the steering motor, and the maximum state includes a maximum achievable motor torque.

15. The system of claim 11, wherein the one or more measurement signals include at least one of a motor position and a motor velocity, and the processing device is configured to calculate a rack force based on a rack force model and calculate the system state based on the estimated rack force and a mass model of the steering system.

16. The system of claim 15, wherein the rack force model includes a bicycle model and a static tire model, the processing device is configured to calculate the rack force by estimating a rolling rack force based on the bicycle model and a static rack force based on the static tire model, and blending the static rack force and the rolling rack force based on vehicle speed to generate a blended rack force.

17. The system of claim 15, wherein the rack force is estimated based on a state observer in combination with a mass model of the system.

18. The system of claim 17, wherein the mass model is a one-mass model.

19. The system of claim 15, wherein the processing device is configured to determine the maximum state by iteratively estimating the state for each of one or more successive time steps, based on a set of differential equations derived from the mass model.

20. The system of claim 11, 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.