Independent control of vehicle wheels

• US 10,488,172 B1
• Filed: 10/18/2017
• Issued: 11/26/2019
• Est. Priority Date: 10/18/2017
• Status: Active Grant

• Current Assignee: Zoox Inc.
• Original Assignee: Zoox Inc.
• Inventors: Funke, Joseph, Edren, Johannes, Javidan, Ali
• Primary Examiner(s): Brown, Drew J
• Application Number:
  US15/787,380
• Time in Patent Office: 769 Days
• CPC Class Codes: B62D 15/0285 Parking performed automatically
• CPC Class Codes: B62D 17/00 Means on vehicles for adjusting camber, castor, or toe-in
• CPC Class Codes: B62D 6/00 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 Class Codes: B62D 6/04 responsive only to forces disturbing the intended course of the vehicle, e.g. forces acting transversely to the direction of vehicle travel
• CPC Class Codes: B62D 7/06 for individually-pivoted wheels, e.g. on king-pins
• CPC Class Codes: B62D 7/159 characterised by computing methods or stabilisation processes or systems, e.g. responding to yaw rate, lateral wind, load, road condition
• CPC Class Codes: G01B 21/26 for testing wheel alignment
• CPC Class Codes: G01B 5/255 for testing wheel alignment

Abstract

An over actuated system capable of controlling wheel parameters, such as speed (e.g., by torque and braking), steering angles, caster angles, camber angles, and toe angles, of wheels in an associated vehicle. The system may determine the associated vehicle is in a rollover state and adjust wheel parameters to prevent vehicle rollover. Additionally, the system may determine a driving state and dynamically adjust wheel parameters to optimize driving, including, for example, cornering and parking. Such a system may also dynamically detect wheel misalignment and provide alignment and/or corrective driving solutions. Further, by utilizing degenerate solutions for driving, the system may also estimate tire-surface parameterization data for various road surfaces and make such estimates available for other vehicles via a network.

Claims

1. A wheel control system for a vehicle having a longitudinal axis extending along a line between a first end of the vehicle and a second end of the vehicle opposite the first end of the vehicle, the wheel control system comprising:

a first steering assembly associated with first wheels;

a wheel controller configured to;

receive a signal indicative of at least one of torque supplied to the first wheels of the vehicle or a lateral force associated with the first steering assembly;

control, based at least in part on the signal, steering angles and one or more of a toe angle, camber angle, or caster angle of the first wheels;

determine misalignment of one or more of the first wheels while the vehicle is travelling; and

at least one of reduce or eliminate the misalignment.

2. The wheel control system of claim 1, wherein the wheel controller is configured to receive a signal indicative of the misalignment, and wherein the signal indicative of the misalignment is based at least in part on a signal generated by a localization system.

3. The wheel control system of claim 2, wherein the localization system is configured to determine one or more of a position or orientation of the vehicle based at least in part on a second signal generated by one or more inertial measurement units coupled to the vehicle.

4. The wheel control system of claim 1, wherein the wheel controller is configured to control one or more of:

toe angles of a first side wheel and a second side wheel of the first wheels, so that the toe angles are a same magnitude in opposite directions;

camber angles of the first side wheel and the second side wheel of the first wheels, so that the camber angles are a same magnitude in opposite directions;

or

caster angles of the first side wheel and the second side wheel of the first wheels, so that the caster angles are a same magnitude in the same direction.

5. The wheel control system of claim 4, further comprising:

a second steering assembly associated with second wheels and configured to control steering angles of the second wheels,

wherein the signal is a first signal, and

wherein the wheel controller is further configured to;

receive a second signal indicative of at least one of;

second torque supplied to the second wheels;

or

a second lateral force associated with the second steering assembly;

and

control, based at least in part on the second signal, steering angles of at least one of the second wheels.

6. The wheel control system of claim 1, further comprising a second steering assembly configured to control steering angles of second wheels,

wherein the signal is a first signal, and wherein the wheel controller is further configured to:

receive a second signal indicative of a direction of travel of the vehicle and a third signal indicative of a direction defined by the longitudinal axis of the vehicle;

determine, based at least in part on the second signal indicative of the direction of travel of the vehicle and the third signal indicative of a direction defined by the longitudinal axis of the vehicle, a second misalignment of one or more of at least one of the second wheels; and

at least one of reduce or eliminate the second misalignment based at least in part in part on the second signal indicative of the direction of travel of the vehicle and the third signal indicative of the direction defined by the longitudinal axis of the vehicle.

7. The wheel control system of claim 6, wherein:

the first steering assembly comprises a first steering rack configured to be coupled to each of the first wheels and control orientation of the first wheels relative to the longitudinal axis of the vehicle;

the second steering assembly comprises a second steering rack configured to be coupled to each of the second wheels and control orientation of the second wheels relative to the longitudinal axis; and

the wheel controller is configured to control operation of the first steering rack and the second steering rack to align the first wheels and the second wheels with the longitudinal axis of the vehicle.

8. The wheel control system of claim 1, further comprising:

a second steering assembly configured to control second steering angles of second wheels; and

wherein the wheel controller is configured to;

control the first steering assembly to change the first steering angles of the first wheels in a first direction; and

control the second steering assembly to change the second steering angles of the second wheels in a second direction having a same sign as the first direction.

9. A method for reducing misalignment of a wheel of a vehicle having a longitudinal axis extending along a line between a first end of the vehicle and a second end of the vehicle opposite the first end of the vehicle, the method comprising:

causing the vehicle to move along a surface;

receiving a signal generated by one or more sensors coupled to the vehicle, the one or more sensors including at least one light detection and ranging sensors (LIDAR);

determining a misalignment of one or more wheels of the vehicle while moving along the surface; and

controlling a wheel control system configured to facilitate control of a vehicle to control one or more of respective steering angles, toe angles, camber angles, or caster angles associated with the one or more wheels of the vehicle to at least one of reduce or eliminate the misalignment of the one or more wheels.

10. The method of claim 9, wherein determining the misalignment of one or more wheels of the vehicle comprises determining a discrepancy between the signal and a trajectory signal from a planner system, and

wherein the one or more sensors further comprise one or more of a global positioning system, an inertial measurement unit, or a camera.

11. The method of claim 9, further comprising, when the vehicle is travelling in a direction aligned with the longitudinal axis of the vehicle, controlling one or more of:

toe angles of a first side wheel and a second side wheel of the wheels, so that the toe angles are a same magnitude in opposite directions;

camber angles of the first side wheel and the second side wheel of the wheels, so that the camber angles are a same magnitude in opposite directions;

or

caster angles of the first side wheel and the second side wheel of the wheels, so that the caster angles are a same magnitude in the same direction.

12. The method of claim 11, wherein determining the misalignment:

is based at least in part on a signal indicative of at least one of;

torque supplied to one or more of the wheels;

a lateral force associated with at least one of a first steering assembly associated with first wheels or a second steering assembly associated with second wheels;

or

a deviation from the direction of travel aligned with the longitudinal axis of the vehicle.

13. The method of claim 9, further comprising:

receiving a second signal indicative of a direction of travel of the vehicle and a third signal indicative of a direction defined by the longitudinal axis of the vehicle; and

wherein determining the misalignment is based at least in part on the second signal indicative of the direction of travel of the vehicle and the third signal indicative of a direction defined by the longitudinal axis of the vehicle.

14. A vehicle comprising:

a chassis having a longitudinal axis extending along a line between a first end of the vehicle and a second end of the vehicle opposite the first end of the vehicle;

first wheels coupled proximate to the first end of the vehicle;

second wheels coupled proximate to the second end of the vehicle; and

a wheel control system comprising a wheel controller configured to;

control steering angles and one or more of a toe angle, a camber angle, or a caster angle of first wheels coupled proximate to the first end of the vehicle;

receive a signal, the signal indicative of at least one of torque supplied to the first wheels or a lateral force associated with at least one of the first wheels;

determine, based at least in part on the signal, misalignment of at least one of the first wheels; and

reduce or eliminate the misalignment.

15. The vehicle of claim 14, wherein the signal is based at least in part on a signal generated by a localization system.

16. The vehicle of claim 15, wherein the localization system is configured to determine one or more of a position or orientation of the vehicle based at least in part on one or more sensors coupled to the vehicle, and wherein the one or more sensors comprise one or more of a global positioning system, an inertial measurement unit, a LIDAR, or a camera.

17. The vehicle of claim 14, wherein the wheel controller is configured to at least one of reduce or eliminate the misalignment by adjusting

camber angles of one or more of at least one of the first wheels or at least one of the second wheels.

18. The vehicle of claim 17,

wherein the wheel controller is configured to control, based at least in part on the signal, one or more of the toe angles, the camber angles, or the caster angles of one or more of at least one of the second wheels.

19. The vehicle of claim 14, further comprising:

a first steering assembly coupled proximate to the first end of the vehicle and configured to control steering angles of the first wheels;

a second steering assembly coupled proximate to the second end of the vehicle and configured to control second steering angles of the second wheels,

wherein the wheel controller is configured to;

receive a second signal indicative of a direction of travel of the vehicle and a third signal indicative of a direction defined by the longitudinal axis of the vehicle and wherein determining the misalignment is based at least in part on the second signal indicative of the direction of travel of the vehicle and the third signal indicative of a direction defined by the longitudinal axis of the vehicle one of the second wheels.

20. The vehicle of claim 14, wherein the wheel controller is configured to at least one of reduce or eliminate the misalignment by adjusting one or more caster angles of one or more of at least one of the first wheels or at least one of the second wheels.