METHOD FOR DETERMINING MISALIGNMENT OF AN OBJECT SENSOR

• US 20160209211A1
• Filed: 01/16/2015
• Published: 07/21/2016
• Est. Priority Date: 01/16/2015
• Status: Active Application

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Zhang, Xian, Song, Xiaofeng Frank, Zeng, Shuqing
• Application Number:
  US14/598,894
• Publication Number:
  US 20160209211A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01B 21/24 for testing alignment of axes
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 17/931 of land vehicles
• CPC Class Codes: G01S 2013/9323 Alternative operation using light waves
• CPC Class Codes: G01S 2013/93271 in the front of the vehicles
• CPC Class Codes: G01S 2013/93272 in the back of the vehicles
• CPC Class Codes: G01S 2013/93274 on the side of the vehicles
• CPC Class Codes: G01S 7/4026 Antenna boresight
• CPC Class Codes: G01S 7/403 in azimuth, i.e. in the horizontal plane
• CPC Class Codes: G01S 7/4972 Alignment of sensor

Abstract

A vehicle system and method that can determine object sensor misalignment while a host vehicle is being driven, and can do so within a single sensor cycle through the use of stationary and moving target objects and does not require multiple sensors with overlapping fields of view. In an exemplary embodiment where the host vehicle is traveling in a generally straight line, one or more object misalignment angle(s) α_o between an object axis and a sensor axis are calculated and used to determine the actual sensor misalignment angle α.

Claims

1. A method for determining misalignment of an object sensor on a host vehicle, comprising the steps of:

determining if the host vehicle is traveling in a straight line;

receiving object sensor readings from the object sensor, and obtaining object parameters from the object sensor readings for at least one object in the object sensor field of view;

when the host vehicle is traveling in a straight line, using the object parameters to calculate an object misalignment angle α

_o between an object axis and a sensor axis for the at least one object; and

using the object misalignment angle α

_o to determine a sensor misalignment angle α

.

2. The method of claim 1, wherein the step of determining if the host vehicle is traveling in a straight line further comprises receiving vehicle sensor readings from at least one of a yaw rate sensor, a wheel speed sensor, or a steering angle sensor, and using the vehicle sensor readings to determine if the host vehicle is traveling in a straight line.

3. The method of claim 1, wherein the step of determining if the host vehicle is traveling in a straight line further comprises determining if a turn signal switch is activated, and using the activation status of the turn signal switch to determine if the host vehicle is traveling in a straight line.

4. The method of claim 1, wherein the object parameters include a coordinate and a coordinate rate for the at least one object.

5. The method of claim 4, wherein the coordinate comprises a range from the host vehicle to the at least one object and an azimuth between the sensor axis and the direction of the at least one object, and the coordinate rate comprises a rate of change of the range and of the azimuth.

6. The method of claim 4, wherein the coordinate comprises an X axis position for the at least one object and a Y axis position for the at least one object, and the coordinate rate comprises a rate of change of the position.

7. The method of claim 5, wherein the following equation is used to calculate the object misalignment angle α

_o;

8. The method of claim 1, wherein the at least one object includes one or more moving objects and one or more stationary objects.

9. The method of claim 1, wherein a plurality of object misalignment angles α

_o are used to determine a cycle misalignment angle α

_c, and the cycle misalignment angle α

_c is used to determine the sensor misalignment angle α

.

10. The method of claim 9, wherein stationary objects are weighted in favor of moving objects when determining the cycle misalignment angle α

_c.

11. The method of claim 9, wherein the object misalignment angle α

_o, the cycle misalignment angle α

_c, or both the object misalignment angle α

_o and the cycle misalignment angle α

_c are used to determine a long term misalignment angle α

_lt, and the long term misalignment angle α

_lt is used to determine the sensor misalignment angle α

.

12. The method of claim 11, wherein a moving average is used to determine the long term misalignment angle α

_lt.

13. The method of claim 11, wherein a first order digital filter is used to determine the long term misalignment angle α

_lt.

14. The method of claim 13, wherein a filter coefficient of the first order digital filter is a calibrated parameter that varies depending on the number of valid objects analyzed in a particular sensor cycle.

15. The method of claim 11, wherein one or more of the following remedial actions are executed based on the long term misalignment angle α

_lt;

compensating for the sensor misalignment angle α

, sending a warning message regarding the sensor misalignment angle α

, establishing a diagnostic trouble code (DTC) representative of the sensor misalignment angle α

, or disabling a device, module, system and/or feature of the host vehicle based on the sensor misalignment angle α

.

16. The method of claim 1, wherein the sensor misalignment angle α

is determined while the host vehicle is being driven and without the need for multiple object sensors with overlapping fields of view.

17. A method for determining misalignment of an object sensor on a host vehicle, comprising the steps of:

determining if the host vehicle is traveling in a straight line;

receiving object sensor readings from the object sensor, and obtaining object parameters from the object sensor readings for at least one object in the object sensor field of view;

determining if the at least one object is a valid object;

when the host vehicle is traveling in a straight line and the at least one object is a valid object, using the object parameters to calculate an object misalignment angle α

_o between an object axis and a sensor axis for the at least one valid object;

using the object misalignment angle α

_o to establish a long term misalignment angle α

_lt; and

using the long term misalignment angle α

_lt to determine a sensor misalignment angle α

.

18. The method of claim 17, wherein the step of determining if the at least one object is a valid object is includes comparing a range rate of the object to a range rate threshold.

19. The method of claim 17, wherein the step of determining if the at least one object is a valid object is includes implementing a reduced field of view for the object sensor comprising an angular threshold, a distance threshold, or both an angular threshold and a distance threshold.

20. The method of claim 19, wherein the distance threshold is determined by comparing a road curvature radius to a road curvature radius threshold.

21. A vehicle system on a host vehicle, comprising:

one or more vehicle sensors providing vehicle sensor readings, the vehicle sensor readings indicate whether or not the host vehicle is traveling in a straight line;

one or more object sensors providing object sensor readings, wherein the object sensor readings include object parameters for at least one object in an object sensor field of view; and

a control module being coupled to the one or more vehicle sensors for receiving the vehicle sensor readings and being coupled to the one or more object sensors for receiving the object sensor readings, wherein the control module is configured to use the object parameters to calculate an object misalignment angle α

_o for the at least one object, the object misalignment angle α

_o being defined by an object axis and a sensor axis, and using the object misalignment angle α

_o to determine a sensor misalignment angle α

.