SYSTEM AND METHOD FOR VEHICLE LATERAL CONTROL

• US 20130253767A1
• Filed: 03/26/2012
• Published: 09/26/2013
• Est. Priority Date: 03/26/2012
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Lee, Jin-Woo, Litkouhi, Bakhtiar Brian
• Granted Patent: US 9,168,924 B2
• Time in Patent Office: Days
• US Class Current: 701/42
• CPC Class Codes: B60W 2540/18 Steering angle
• CPC Class Codes: B60W 30/12 Lane keeping
• CPC Class Codes: B60W 50/04 Monitoring the functioning of the control system
• CPC Class Codes: B62D 15/025 Active steering aids, e.g. helping the driver by actively influencing the steering system after environment evaluation B62D1/28 takes precedence

Abstract

A lane controller system installed on a vehicle may include components for self-diagnosing malfunctions on the vehicle. The system may include a desired path generator for generating a desired path that keeps the vehicle within a road lane; a steering controller for providing steering a steering correction to keep the vehicle within the road lane; a vehicle state estimator for estimating the state of the vehicle; a lane marking detector for detecting position of road lane markings; a path predictor for predicting a path actively followed by the vehicle; a virtual dynamics module for modeling the anticipated path of the vehicle following input of the steering controller; a comparer that compares the results of actual steering corrections applied with those predicted by the virtual dynamics module, and a diagnostic system that determines a root cause of malfunctions, based on the comparison by the comparer.

Claims

1. A lane controller system installed on a vehicle, comprising:

(i) a path generator for generating a desired path for controlling the vehicle within a lane of a road;

(ii) a steering controller for applying a steering correction in order to maintain the vehicle'"'"'s movement on the desired path as determined by the path generator;

(iii) a vehicle state estimator for estimating a state of the vehicle;

(iv) a lane marking detector for detecting lane markings indicating the lane'"'"'s boundaries, wherein said desired path is based on feedback from the lane marking detector and said state of the vehicle;

(v) a path predictor for predicting a path actively followed by the vehicle, based on the vehicle'"'"'s current speed, acceleration, yaw rate, and steering angle, wherein said steering correction is to modify the vehicle'"'"'s predicted path, if the predicted path is different from the desired path;

(vi) a virtual dynamics module for modeling an anticipated path of the vehicle based on the steering corrections applied by the steering controller;

(vii) a comparer for comparing an actual path taken by the vehicle when the steering correction is applied with the anticipated path modeled by the virtual dynamics module; and

(viii) a diagnostic system for diagnosing a cause of differences between the actual path taken and the anticipated path, if the differences are above a threshold.

2. The lane controller system of claim 1, wherein said lane controller system is linked to at least one sensor for monitoring the road.

3. The lane controller system of claim 2,

wherein the at least one sensor comprises at least one of the group consisting of video sensors in visual domain, laser sensors, infrared sensors, stereo cameras, and radar sensors;

and

wherein the at least one sensor monitors at least one of dashed lane markings, solid white lines, double lines, colored lines, or road curb.

4. The lane controller system of claim 1, wherein said lane controller system is a component of a lane keeping assist, lane centering, and lane changing system.

5. The lane controller system of claim 1, wherein the threshold is a variable threshold dependent on at least one factor selected from the group consisting of vehicle speed, a road condition, curvature of the road, steering system dynamics and type of vehicle.

6. The lane controller system of claim 1, wherein the cause diagnosed by the diagnostic system is selected from the group consisting of externalities, mechanical malfunctioning of the steering system and sensor misalignment.

7. The lane controller system of claim 1, wherein the cause diagnosed by the diagnostic system is selected from the group consisting of wheel imbalance, wheel mis-alignment, flat tires, EPS torque imbalance, lane sensor mis-positioning, camera mis-positioning and camera misalignment in yaw angle.

8. The lane controller system of claim 1, wherein the comparer receives input concerning actual steering correction from at least one vehicle dynamics measurement device wherein the at least one vehicle dynamics measurement device monitors at least one of the group comprising steering angle, steering torque, steering direction, angular acceleration, linear acceleration, yaw-rate, velocity, speed and wheel rotation.

9. The lane controller system of claim 1, wherein the comparer receives input concerning actual steering correction from at least one vehicle dynamics measurement device including at least one of the group consisting of steering angle sensors and steering torque sensors associated with a component of the steering system.

10. The lane controller system of claim 9, wherein the component of the steering system is selected from the group comprising steering wheels, steering columns, steering rack and pinions and vehicle axles.

11. The lane controller system of claim 1, wherein the comparer receives input concerning actual steering correction from at least one vehicle dynamics measurement device selected from the group consisting of accelerometers, speedometers, wheel speed sensors, and inertial measurement units (IMU).

12. The lane controller system of claim 1, wherein measured vehicle dynamics are received from at least one vehicle dynamics measurement device via at least one of a wire link and a wireless link.

13. The lane controller system of claim 1, wherein said lane controller system is part of a system for lane monitoring or lane keeping, wherein said system comprises at least one processor, memory, long term storage, at least one user input component, and at least one output component.

14. The lane controller system of claim 13 further comprising a data base selected from the group of freestanding databases, memory and long term storage.

15. A method for self-diagnosing malfunctions on a vehicle comprising the steps of:

(d) upon receiving a request from a driver for lane centering assistance, checking that lane centering functionality is actually available and, engaging a lane centering system;

(e) calculating an appropriate lane centering adjustment;

(f) applying an adjustment to the vehicle'"'"'s motion via a steering controller;

(g) applying the adjustment of step (e) to a virtual vehicle dynamics module, thereby calculating an anticipated vehicle motion;

(h) recording actual vehicle motion resulting from the steering adjustment of step (0;

(i) comparing the actual vehicle motion and the anticipated vehicle motion, over an appropriate distance;

(j) if, based on the comparison, a difference between the actual vehicle motion and the anticipated vehicle motion is less than a threshold amount, recalculating the appropriate lane centering adjustment;

(k) if, based on the comparison, a difference between the actual vehicle motion and the anticipated vehicle motion is greater than a threshold amount, diagnosing a cause for the difference, wherein the cause comprises at least one of wheel imbalance, wheel mis-alignment, flat tires, torque imbalance, lane sensor mis-positioning, camera mis-positioning and camera mis-alignment.

16. The method of claim 15, further comprising steps of:

(a) determining whether the lane centering system is engaged or disengaged;

(b) if the lane centering system is disengaged, checking if the driver is requesting lane centering assistance;

if the driver is not requesting lane centering assistance, rerunning the lane centering disengagement, and

(c) rerunning stages ‘

a’ and

‘

b’

according to a schedule selected from the group consisting of;

continuously during a journey;

when the vehicle moves from a substantially stationary position;

when an onboard computer detects freeway or highway driving;

when a GPS system is activated;

during on-road driving;

intermittently at a predetermined distance interval; and

intermittently at a predetermined time interval.

17. The method of claim 15, wherein said diagnosing comprises comparing a bias in steering torque to a predetermined limit, if the bias in steering torque is greater than the predetermined limit, then diagnosing a cause as attributable to a steering malfunctioning, if the bias in steering torque is less than the predetermined limit, then diagnosing a cause as attributable to a sensor system.

18. The method of claim 17, wherein if the bias in steering torque exceeds the predetermined limit, further comprising:

if a match is detected in the vehicle'"'"'s rack and pinion system, then diagnosing the cause as related to wheel imbalance or under-pressured tires; and

if a mismatch is detected in the vehicle'"'"'s rack and pinion system, then diagnosing the cause as steering bias or inaccurate angle sensor;

wherein if the bias in the steering torque is less than predetermined limit, further comprising;

if the driver'"'"'s preferred lane offset is such that the offset is always biased, then diagnosing the cause as lane sensor mis-positioning, and

if the driver'"'"'s preferred lane offset is such that there is continuous oscillatory motion even when travelling on relatively straight roads, then diagnosing the cause as a camera misalignment in yaw angle.

19. A computer software product for installing on a processor of a vehicle, the computer software product including a medium readable by a processor, the medium having stored thereon:

(ii) a second set of instructions for receiving a request, from a driver, for lane centering assistance, checking that lane centering functionality is actually available and engaging a lane centering system;

(iii) a third set of instructions for calculating an appropriate steering adjustment;

(iv) a fourth set of instructions for applying the adjustment to a steering mechanism of the vehicle;

(v) a fifth set of instructions for providing a vehicle dynamics simulation;

(vi) a sixth set of instructions for applying the adjustment to the vehicle dynamics simulation;

(vii) a seventh set of instructions for recording actual vehicle motion caused by the steering adjustment;

(viii) an eighth set of instructions for calculating an anticipated vehicle motion;

(ix) a ninth set of instructions for comparing the actual recorded motion and the calculated anticipated vehicle motion, over an appropriate distance;

(x) a tenth set of instructions, wherein if the difference detected based on the ninth set of instructions is less than a threshold amount, then recalculating the appropriate lane centering adjustment; and

if the difference detected based on the ninth set of instructions is greater than a threshold amount, then diagnosing a cause for the detected difference.

20. The computer software product of claim 19 wherein the diagnosable root cause is selected from the group consisting of wheel imbalance, wheel mis-alignment, flat tires, EPS torque balance, lane sensor mis-positioning, camera mis-positioning and camera misalignment in yaw angle.