Machine sensor calibration system

• US 9,279,882 B2
• Filed: 09/19/2008
• Issued: 03/08/2016
• Est. Priority Date: 09/19/2008
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Hukkeri, Ramadev Burigsay, Edara, Thandava Krishna
• Primary Examiner(s): Satanovsky, Alexander
• Application Number:
  US12/232,565
• Publication Number:
  US 20100076708A1
• Time in Patent Office: 2,727 Days
• Field of Search: 702/94, 702/95, 702/151, 702/152, 702/153
• US Class Current: 1/1
• CPC Class Codes: G01S 7/40 Means for monitoring or calibrating
• CPC Class Codes: G01S 7/4082 using externally generated reference signals, e.g. via remote reflector or transponder
• CPC Class Codes: G01S 7/497 Means for monitoring or calibrating
• CPC Class Codes: G01S 7/4972 Alignment of sensor
• CPC Class Codes: G01S 7/52004 Means for monitoring or calibrating short-range imaging G01S7/5205

Abstract

A sensor calibration system for a mobile machine is disclosed. The sensor calibration system may have a positioning device configured to determine a desired sensing location on the mobile machine, a calibration object, and a sensor configured to sense a characteristic of the calibration object from an actual sensing location on the mobile machine and to generate a corresponding signal. The sensor calibration system may also have a controller in communication with the sensor and the positioning device. The controller may be configured to compare the characteristic sensed from the actual sensing location to a known characteristic associated with the desired sensing location, and to determine a difference between the actual sensing location and the desired sensing location based on the comparison. The controller may further be configured to correct subsequent signals generated by the sensor based on the difference.

Claims

1. A sensor calibration system for a mobile machine, comprising:

a positioning device configured to determine a position of the mobile machine;

a calibration object;

a sensor configured to sense a characteristic of the calibration object from an actual sensing location of the sensor on the mobile machine and to generate a corresponding signal; and

a controller in communication with the sensor and the positioning device, the controller including a plurality of maps including known characteristics determined at different positions of the mobile machine relative to the calibration object and sensed from a desired sensing location of the sensor on the mobile machine, the controller being configured to;

communicate with the positioning device and select a map from the plurality of maps related to the position of the mobile machine with respect to the calibration object,

compare the characteristic sensed from the actual sensing location of the sensor to the known characteristic from the map that was previously sensed from the desired sensing location of the sensor;

determine a difference between the actual sensing location of the sensor and the desired sensing location of the sensor based on the comparison; and

correct subsequent signals generated by the sensor at the actual sensing location based on the difference by applying one or more transformations to the signal.

2. The sensor calibration system of claim 1, wherein the positioning device is a global positioning device configured to determine a reference location on the mobile machine, the desired sensing location being determined as a function of the reference location.

3. The sensor calibration system of claim 2, wherein the desired sensing location includes a position and an orientation relative to the reference location.

4. The sensor calibration system of claim 1, wherein the calibration object includes a plurality of features, each feature having a different characteristic detectable by the sensor.

5. The sensor calibration system of claim 1, wherein the sensor is one of a RADAR sensor, a SONAR sensor, a LIDAR sensor, and a camera.

6. The sensor calibration system of claim 1, wherein a difference between the characteristic sensed from the actual sensing location and the known characteristic sensed from the desired sensing location corresponds with a shift of the actual sensing location in any of three orthogonal directions relative to the desired sensing location.

7. The sensor calibration system of claim 6, wherein the difference between the characteristic sensed from the actual sensing location and the known characteristic sensed from the desired sensing location also corresponds with a rotation of the actual sensing location about any of three orthogonal axis relative to the desired sensing location.

8. The sensor calibration system of claim 7, wherein the controller is configured to correct subsequent characteristics sensed from the actual sensing location by amounts corresponding to the shift and the rotation of the actual sensing location relative to the desired sensing location.

9. The sensor calibration system of claim 1, wherein the controller includes a memory having stored therein a plurality of transformation algorithms corresponding to the shift and the rotation differences between the actual sensing location and the desired sensing location.

10. The sensor calibration system of claim 1, wherein the controller includes a memory having stored therein the known characteristic as sensed by a plurality of sensor types from the desired sensing location.

11. The sensor calibration system of claim 1, wherein the controller is configured to correct subsequent signals only if the difference is greater than a threshold amount.

12. A method of calibrating a sensor mounted on a mobile machine, the method comprising:

positioning the mobile machine proximate a calibration object;

communicating with a positioning device to determine a position of the mobile machine with respect to the calibration object and selecting a map from a plurality of maps related to the position of the mobile machine with respect to the calibration object, wherein the plurality of maps include known characteristics determined at different positions of the mobile machine relative to the calibration object and sensed from a desired sensing location of a sensor on the mobile machine;

sensing with the sensor a characteristic of the calibration object from an actual sensing location of the sensor on the mobile machine;

comparing the characteristic sensed from the actual sensing location to the known characteristic associated with the desired sensing location;

determining a difference between the sensed characteristic and the known characteristic based on the comparison; and

correcting subsequent sensor input received from the actual sensing location based on the difference by applying one or more transformations to the input.

13. The method of claim 12, further including determining a global position of a reference location on the mobile machine relative to the calibration object, and calculating the desired sensing location as a function of the reference location.

14. The method of claim 13, wherein the desired sensing location includes a position and an orientation relative to the reference location.

15. The method of claim 12, wherein a difference between the characteristic sensed from the actual sensing location and the known characteristic corresponds with a shift of the actual sensing location in any of three orthogonal directions relative to the desired sensing location.

16. The method of claim 15, wherein the difference between the characteristic sensed from the actual sensing location and the known characteristic corresponds with a rotation of the actual sensing location about any of three orthogonal axis relative to the desired sensing location.

17. The method of claim 16, wherein correcting subsequent sensor input includes transforming future characteristics sensed from the actual sensing location by amounts corresponding to the shift and the rotation of the actual sensing location relative to the desired sensing location.

18. The method of claim 12, further including storing the characteristic sensed from the actual sensing location in memory as a known characteristic when the actual sensing location substantially matches the desired sensing location.