Method of controlling steering of a ground vehicle

Patent metadata

Field	Value
Publication number	US-9254866-B2
Application number	US-201314075262-A
Country	US
Kind code	B2
Filing date	Nov 8, 2013
Priority date	Nov 8, 2013
Publication date	Feb 9, 2016
Grant date	Feb 9, 2016

Abstract

A method of controlling steering of a vehicle through setting wheel angles of a plurality of modular electronic corner assemblies (eModules) is provided. The method includes receiving a driving mode selected from a mode selection menu. A position of a steering input device is determined in a master controller. A velocity of the vehicle is determined, in the master controller, when the determined position of the steering input device is near center. A drive mode request corresponding to the selected driving mode to the plurality of steering controllers is transmitted to the master controller. A required steering angle of each of the plurality of eModules is determined, in the master controller, as a function of the determined position of the steering input device, the determined velocity of the vehicle, and the selected first driving mode. The eModules are set to the respective determined steering angles.

First claim

The invention claimed is:

1. A method of controlling steering of a vehicle through setting wheel angles of a plurality of modular electronic corner assemblies (eModules), the method comprising:
receiving a driving mode selected from a mode selection menu;
determining, in a master controller, a position of a steering input device;
determining, in the master controller, a velocity of the vehicle when the determined position of the steering input device is near center;
transmitting a drive mode request corresponding to the driving mode to a plurality of steering controllers when the steering wheel is near center and the velocity of the vehicle is below a maximum velocity;
determining, in the master controller, a required steering angle of each of the plurality of eModules as a function of the determined position of the steering input device, the determined velocity of the vehicle, and the driving mode; setting each of the eModules to an angle of 0 degrees and recording the angle setting of each of the eModules to a memory in the master controller, when the determined position of the steering input device is near 0 degrees; and
setting the eModules to the respective determined steering angles.

2. A method, as set forth in claim 1 , wherein the plurality of eModules are a left front (LF) eModule, a right front (RF) eModule, a left rear (LR) eModule, and a right rear (RR) eModule.

3. A method, as set forth in claim 2 , wherein determining, in the master controller, a required steering angle is further defined as:
calculating a steering angle when the determined position of the steering input device is not near 0 degrees;
setting an instantaneous center of rotation (ICR) to be along a centerline of rear wheels of the LR eModule and the RR eModule;
setting each of the LR and RR eModules to an angle;
calculating a coordinate position of the ICR as a function of the calculated steering angle;
calculating angles of the LF eModule and RF eModule;
calculating a wheel angle of the LF eModule and the RF eModule; and
recording the wheel angle of the LF eModule and the RF eModule to the memory in the master controller.

4. A method, as set forth in claim 3 , wherein setting each of the LR and RR eModules to an angle is further defined as setting each of the LR and RR eModules to an angle of 0 degrees when the drive mode request is a two-wheel steer (2WS) drive mode request.

5. A method, as set forth in claim 3 , further comprising:
calculating a caster wheel offset for the LF eModule and the RF eModule; and
calculating wheel angle offsets for the LF eModule and the RF eModule to align a center of each of the respective wheels to the ICR;
wherein calculating a wheel angle of the LF eModule and the RF eModule is further defined as calculating a wheel angle of the LF eModule and the RF eModule as a function of the alignment of the center of each of the respective wheels to the ICR.

6. A method, as set forth in claim 3 , wherein receiving a driving mode selected from the mode selection menu is further defined as receiving a four wheel steer (4WS) drive mode request from the mode selection menu when the vehicle is operating in a 2WS drive mode; and
wherein setting the LR and RR eModules to an angle is further defined as:
setting the LR and RR eModules to an angle of 0 degrees when the velocity of the vehicle is greater than a maximum velocity;
setting the LR and RR eModules to a desired angle when the velocity of the vehicle is no greater than a minimum velocity; and
transitioning the angle of the LR and RR eModules linearly from the angle of 0 degrees to the desired angle when the velocity of the vehicle is greater than the minimum velocity and no greater than the maximum velocity.

7. A method, as set forth in claim 2 , wherein determining, in the master controller, a required steering angle is further defined as:
calculating an ICR lateral line offset as a function of the determined velocity of the vehicle when the drive mode request is the 4WS drive mode;
calculating a steering angle when the determined position of the steering input device is not near 0 degrees;
calculating a coordinate position of the ICR as a function of the calculated steering angle;
calculating angles of the LF eModule, the RF eModule, the LR eModule, and the RR eModule;
calculating a wheel angle of the LF eModule, the RF eModule, the LR eModule, and the RR eModule; and
recording the wheel angle of the LF eModule, the RF eModule, the LR eModule, and the RR eModule to the memory in the master controller.

8. A method, as set forth in claim 7 , further comprising:
calculating a caster wheel offset for the LF eModule, the RF eModule, the LR eModule, and the RR eModule; and
calculating wheel angle offsets for the LF eModule, the RF eModule, the LR eModule, and the RR eModule to align a center of each of the respective wheels to the ICR;
wherein calculating a wheel angle of the LF eModule, the RF eModule, the LR eModule, and the RR eModule is further defined as calculating a wheel angle of the LF eModule, the RF eModule, the LR eModule, and the RR eModule as a function of the alignment of the center of each of the respective wheels to the ICR.

9. A method, as set forth in claim 7 , further comprising:
wherein calculated ICR lateral line is configured to intersect a center of the vehicle when the determined velocity of the vehicle is no greater than a minimum velocity;
wherein the calculated ICR lateral line is configured to intersect the center of the wheels of each of the LR eModule and RR eModule when the determined velocity of the vehicle is greater than a maximum velocity; and
wherein the calculated ICR lateral line is configured to transition linearly between center of the vehicle and the center of the wheels of each of the LR eModule and the RR eModule when the determined vehicle as a function of the linear transition between the determined velocity of the vehicle of between greater than the minimum velocity and no greater than the maximum velocity.

10. A method, as set forth in claim 2 , wherein determining, in the master controller, a required steering angle is further defined as:
calculating an directional vector as a function of the determined position of the steering input device;
determining a normalized yaw angle of a joystick input device about a Z-axis;
calculating a steering angle when the determined normalized yaw angle of the joystick is less than a minimum angle or greater than a maximum angle;
calculating a steering radius from the center of the vehicle;
calculating a coordinate position of the ICR as a function of the calculated steering radius and directional vector;
calculating angles of the LF eModule, the RF eModule, the LR eModule, and the RR eModule;
calculating a wheel angle of the LF eModule, the RF eModule, the LR eModule, and the RR eModule; and
recording the wheel angle of the LF eModule, the RF eModule, the LR eModule, and the RR eModule to the memory in the master controller.

11. A method, as set forth in claim 10 , further comprising:
calculating a caster wheel offset for the LF eModule, the RF eModule, the LR eModule, and the RR eModule; and
calculating wheel angle offsets for the LF eModule, the RF eModule, the LR eModule, and the RR eModule to align a center of each of the respective wheels to the ICR;
wherein calculating a wheel angle of the LF eModule, the RF eModule, the LR eModule, and the RR eModule is further defined as calculating a wheel angle of the LF eModule, the RF eModule, the LR eModule, and the RR eModule as a function of the alignment of the center of each of the respective wheels to the ICR.

12. A method, as set fo

Assignees

• Gm Global Tech Operations Inc
• Nasa

Inventors

• Dawson Andrew D
• Bluethmann William J
• Lee Chunhao J
• Vitale Robert L
• Guo Raymond
• Atluri Venkata Prasad

Classifications

• B62D6/002 Primary

  computing target steering angles for front or rear wheels (B62D7/159 takes precedence) · CPC title

• B60K17/356

  having fluid or electric motor, for driving one or more wheels · CPC title

• B60K7/0007

  the motor being electric · CPC title

• B60K17/358

  all driven wheels being steerable · CPC title

• B60K17/30

  the ultimate propulsive elements, e.g. ground wheels, being steerable · CPC title