Sensor alignment process and tools for active safety vehicle applications

• US 8,775,064 B2
• Filed: 05/10/2011
• Issued: 07/08/2014
• Est. Priority Date: 05/10/2011
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Zeng, Shuqing, Nickolaou, James N., Osinski, David A.
• Primary Examiner(s): Jabr, Fadey
• Assistant Examiner(s): WEEKS, MARTIN A
• Application Number:
  US13/104,704
• Publication Number:
  US 20120290169A1
• Time in Patent Office: 1,155 Days
• Field of Search: 701/1, 701/29, 701/301, 702/94
• US Class Current: 701/301
• CPC Class Codes: G01S 13/862 Combination of radar systems with sonar systems
• CPC Class Codes: G01S 13/865 Combination of radar systems with lidar systems
• CPC Class Codes: G01S 13/867 Combination of radar systems with cameras
• CPC Class Codes: G01S 13/878 Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector G01S13/874 takes precedence
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/93271 in the front of the vehicles
• CPC Class Codes: G01S 2013/93275 in the bumper area
• 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 7/4091 during normal radar operation
• CPC Class Codes: G01S 7/4972 Alignment of sensor
• CPC Class Codes: G08G 1/163 involving continuous checking

Abstract

A method and tools for virtually aligning object detection sensors on a vehicle without having to physically adjust the sensors. A sensor misalignment condition is detected during normal driving of a host vehicle by comparing different sensor readings to each other. At a vehicle service facility, the host vehicle is placed in an alignment target fixture, and alignment of all object detection sensors is compared to ground truth to determine alignment calibration parameters. Alignment calibration can be further refined by driving the host vehicle in a controlled environment following a leading vehicle. Final alignment calibration parameters are authorized and stored in system memory, and applications which use object detection data henceforth adjust the sensor readings according to the calibration parameters.

Claims

1. A method for virtually aligning object detection sensors on a host vehicle, said method comprising:

detecting a sensor misalignment condition during normal driving of the host vehicle, including determining that a set of prerequisite driving conditions exists, computing differences between readings from each of the object detection sensors, and determining if one or more of the object detection sensors is misaligned by an amount which exceeds a predefined threshold where the set of prerequisite driving conditions includes driving on a straight, road and a presence of a leading vehicle on the road ahead of the host vehicle;

determining, by a microprocessor, alignment calibration parameters for the object detection sensors using an alignment target fixture with known ground truth, including placing the host vehicle at a known location in the alignment target fixture and statically measuring a position of one or more objects with each of the object detection sensors, where an actual position of the one or more objects relative to the host vehicle is known as established by the alignment target fixture;

storing the alignment calibration parameters in memory; and

using the alignment calibration parameters by an application program to adjust readings from the object detection sensors.

2. The method of claim 1 further comprising notifying a driver of the host vehicle of the misalignment condition.

3. The method of claim 1 wherein storing the alignment calibration parameters in memory includes attaching a technician tool to the host vehicle by a service technician, and using the technician tool to authorize the storage of the alignment calibration parameters in memory.

4. The method of claim 1 further comprising refining and validating the alignment calibration parameters by driving the host vehicle in a predetermined arrangement behind a leading vehicle.

5. The method of claim 4 wherein refining and validating the alignment calibration parameters includes driving the host vehicle behind the leading vehicle on a straight road, taking a sequence of sensor readings, and minimizing a mathematical function containing the sensor readings and the alignment calibration parameter which corresponds to the sensor readings.

6. The method of claim 1 wherein the object detection sensors include a left-side short-range radar, a right-side short range radar, and a long range radar.

7. The method of claim 1 wherein the application program is a collision detection alert or collision avoidance system.

8. A method for virtually aligning object detection sensors on a host vehicle, said object detection sensors including two short-range radar sensors and a long-range radar sensor, said method comprising:

detecting a sensor misalignment condition during normal driving of the host vehicle;

determining, by a microprocessor, alignment calibration parameters for the object detection sensors using an alignment target fixture with known ground truth, including placing the host vehicle at a known location in the alignment target fixture and statically measuring a position of one or more objects with each of the object detection sensors, where an actual position of the one or more objects relative to the host vehicle is known as established by the alignment target fixture;

refining and validating the alignment calibration parameters by driving the host vehicle in a predetermined arrangement behind a leading vehicle;

authorizing the storage of the alignment calibration parameters and storing the parameters in memory; and

using the alignment calibration parameters by a collision detection alert or collision avoidance system to adjust readings from the object detection sensors.

9. The method of claim 8 wherein detecting a sensor misalignment condition includes determining that a set of prerequisite driving conditions exists, computing differences between readings from each of the object detection sensors, and determining if one or more of the object detection sensors is misaligned by an amount which exceeds a predefined threshold.

10. The method of claim 8 wherein refining and validating the alignment calibration parameters includes driving the host vehicle behind the leading vehicle on a straight road, taking a sequence of sensor readings, and minimizing a mathematical function containing the sensor readings and the alignment calibration parameter which corresponds to the sensor readings.

11. A virtual alignment system for object detection sensors on a host vehicle, said system comprising:

a plurality of object detection sensors on the host vehicle, including a left-side short-range radar, a right-side short range radar, and a long range radar;

an application program module which uses signals from the object detection sensors;

a memory module for storing parameter data for the object detection sensors;

a display unit for providing information to a driver of the host vehicle;

a controller in communication with the object detection sensors, the application program module, the memory module, and the display unit, said controller being configured to determine alignment calibration parameters and adjust the signals from the object detection sensors using the alignment calibration parameters, where the controller is configured to determine alignment calibration parameters for the object detection sensors when the host vehicle is positioned at a known location in an alignment target fixture and a position of one or more objects is measured with each of the object detection sensors, and where an actual position of the one or more objects relative to the host vehicle is known as established by the alignment target fixture; and

a technician tool adapted to communicate with the controller, said technician tool being used to authorize changes to the alignment calibration parameters.

12. The virtual alignment system of claim 11 wherein the application program module includes a collision detection alert or collision avoidance system.

13. The virtual alignment system of claim 11 wherein the controller is configured to detect a sensor misalignment condition during driving of the host vehicle under a set of prerequisite driving conditions.

14. The virtual alignment system of claim 11 wherein the controller is configured to refine and validate the alignment calibration parameters by driving the host vehicle behind a leading vehicle on a straight road, taking a sequence of sensor readings, and minimizing a mathematical function containing the sensor readings and the alignment calibration parameter which corresponds to the sensor readings.

15. A method for virtually aligning object detection sensors on a host vehicle, said method comprising:

detecting a sensor misalignment condition during normal driving of the host vehicle;

determining, by a microprocessor, alignment calibration parameters for the object detection sensors using an alignment target fixture with known ground truth, including placing the host vehicle at a known location in the alignment target fixture and statically measuring a position of one or more objects with each of the object detection sensors, where an actual position of the one or more objects relative to the host vehicle is known as established by the alignment target fixture;

refining and validating the alignment calibration parameters by driving the host vehicle in a predetermined arrangement behind a leading vehicle, including driving the host vehicle behind the leading vehicle on a straight road, taking a sequence of sensor readings, and minimizing a mathematical function containing the sensor readings and the alignment calibration parameter which corresponds to the sensor readings;

storing the alignment calibration parameters in memory; and

using the alignment calibration parameters by an application program to adjust readings from the object detection sensors.

16. A virtual alignment system for object detection sensors on a host vehicle, said system comprising:

a plurality of object detection sensors on the host vehicle;

an application program module which uses signals from the object detection sensors;

a memory module for storing parameter data for the object detection sensors;

a display unit for providing information to a driver of the host vehicle;

a controller in communication with the object detection sensors, the application program module, the memory module, and the display unit, said controller being configured to determine alignment calibration parameters and adjust the signals from the object detection sensors using the alignment calibration parameters, where the controller is configured to determine alignment calibration parameters for the object detection sensors when the host vehicle is positioned at a known location in an alignment target fixture and a position of one or more objects is measured with each of the object detection sensors, and where an actual position of the one or more objects relative to the host vehicle is known as established by the alignment target fixture, and where the controller is also configured to refine and validate the alignment calibration parameters by driving the host vehicle behind a leading vehicle on a straight road, taking a sequence of sensor readings, and minimizing a mathematical function containing the sensor readings and the alignment calibration parameter which corresponds to the sensor readings; and

a technician tool adapted to communicate with the controller, said technician tool being used to authorize changes to the alignment calibration parameters.