Fault tolerant wheel alignment head and system

• US 7,684,026 B2
• Filed: 07/27/2007
• Issued: 03/23/2010
• Est. Priority Date: 07/27/2007
• Status: Active Grant

• Current Assignee: Snap-On Incorporated
• Original Assignee: Snap-On Incorporated
• Inventors: Rogers, Steven C., Bryan, Eric, Brown, Adam C.
• Primary Examiner(s): Tarcza; Thomas H
• Assistant Examiner(s): Ratcliffe; Luke D
• Application Number:
  US11/829,414
• Publication Number:
  US 20090027662A1
• Time in Patent Office: 970 Days
• Field of Search: 356 301- 315, 356 401- 41, 356 501- 515, 356 6- 22, 356/28, 356/28.5, 35613901-1391
• US Class Current: 356/139.09
• CPC Class Codes: G01B 11/2755 using photoelectric detection means
• CPC Class Codes: G01B 2210/12 Method or fixture for calibrating the wheel aligner
• CPC Class Codes: G01B 2210/14 One or more cameras or other optical devices capable of acquiring a two-dimensional image
• CPC Class Codes: G01B 2210/16 Active or passive device attached to the chassis of a vehicle
• CPC Class Codes: G01B 2210/30 Reference markings, reflector, scale or other passive device
• CPC Class Codes: G01B 2210/58 Wireless transmission of information between a sensor or probe and a control or evaluation unit

Abstract

A sensing head and system utilizes fault tolerant design and self-diagnosis. Alternative operation modes are provided when one or more functional modules or components fail. Unique designs provide redundant system resources. Self-diagnoses and tests are provided to isolate and identify sources of malfunctions.

Claims

1. A sensing head for use in a wheel alignment system, comprising:

one or more functional modules, each of which is configured to perform a function usable in obtaining measurements for calculating wheel alignment parameters of a vehicle, wherein the functional modules include at least one of;

a wireless communication interface module configured to communicate in a wireless manner with a computer system or a companion sensing head attached to the vehicle;

a spatial relationship sensing module configured to measure a spatial relationship between the sensing head and the companion sensing head;

an image sensing module configured to producing image data representing an image taken of a target associated with a vehicle wheel; and

an illumination module configured to illuminate the target;

a data processor configured to calculate the measurements based on data received from the one or more functional modules;

wherein the one or more functional modules provide operation redundancy by utilizing at least one of;

providing multiple sets of illumination devices in the illumination module, wherein at least one set is independent from another set and is configured to illuminate the target independently;

providing multiple sets of illumination devices to the spatial relationship sensing module, wherein at least one set is independent from another set and is configured to independently generate a signal to the companion sensing head; and

providing multiple processing units for implementing the data processor, wherein each processing unit is configured to independently perform the functions of the data processor.

2. The sensing head of claim 1, wherein the wireless communication interface includes a first wireless communication interface configured to communicate with the computer system and a second wireless communication interface configured to communicate with the companion sensing head.

3. The sensing head of claim 1 further providing multiple paths for communication with the computer system using the wireless communication module, wherein:

at least one of the paths is different from another path, and

the one or more functional modules are configured to;

when one set of the illumination devices fails, switches operation to another set of illumination devices for illuminating the target;

when one path of the wireless communication with the computer system fails, switch to another communication path for communicating with the computer system;

when one set of the illumination devices of the spatial relationship sensing module fails, switch to another set of illumination devices for generating the signal to the companion sensing head; and

when one of the processing units fails, switch operation to another processing unit for handling tasks of the failed processing unit.

4. The sensing head of claim 1, wherein the multiple sets of illumination devices are configured to illuminate the target alternately.

5. A sensing head for use in a wheel alignment system, comprising:

one or more functional modules, each of which is configured to perform a function usable in obtaining measurements for calculating wheel alignment parameters of a vehicle; and

a data processor, coupled to the one or more functional modules, configured to process data;

wherein;

at least one of the functional modules is configured to perform a self test of a respective functional module; and

the data processor determines an operation condition of the respective functional module based on data related to the self test performed with respect to the respective functional module.

6. The sensing head of claim 5, wherein an indication signal indicating a malfunction of the sensing head is generated based on the data related to the self test performed with respect to the respective functional module.

7. The sensing head of claim 6, wherein the indication signal identifies at least one faulty functional module based on the self test performed with respect to the respective functional module.

8. The sensing head of claim 5, wherein the one or more functional modules include at least one of:

a spatial relationship sensing module for measuring a spatial relationship between the sensing head and a companion sensing head;

an image sensing module for producing image data representing an image taken of a target associated with a vehicle wheel;

an inclinometer;

a rotary sensor;

a wireless communications module; and

an illumination module configured to illuminate the target.

9. The sensing head of claim 8, wherein:

the self test with respect to the image sensing module is performed by producing a test signal associated with the image sensing module;

the spatial relationship sensing module includes an image sensor for sensing a signal projected from the companion sensing head, an emitting device for projecting a signal to be sensed by the companion sensing head, and a test emitting device configured to illuminate the image sensor on the spatial relationship sensing module;

the self test with respect to the spatial relationship sensing module is performed by commanding the test emitting device to illuminate the image sensor and determine an operation condition of the image sensor of the spatial relationship sensing module based on signals generated by the image sensor of the spatial relationship sensor in response to the illumination by the test emitting device;

the inclinometer is implemented with MEMS sensor; and

the self test with respect to the inclinometer is performed by self-generating a beam deflection in the MEMS sensor and analyzing the signal generated by the beam deflection.

10. The sensing head of claim 5, wherein responsive to at least one of the functional modules having an abnormal operation condition, the data processor generates a control signal to turn off the power to the abnormal functional module or to isolate the abnormal functional module from a data bus coupling the abnormal functional module to the data processor or another functional module.

11. The sensing head of claim 5 further comprising a user interface, wherein responsive to at least one of the functional modules having an abnormal operation condition, the user interface conveys information indicating that the sensing head is not working properly.

12. The sensing head of claim 5 further comprising a user interface, wherein if the data processor determines that the one or more functional modules are working properly, the user interface conveys information indicating that the sensing head is in a normal operation condition.

13. A sensing head for use in a wheel alignment system, comprising:

means for performing at least one function usable in obtaining measurements for calculating wheel alignment parameters of a vehicle; and

data processing means, coupled to the means for performing at least one function, for processing data; and

self test means for performing a self test of the means for performing at least one function;

wherein the data processing means determines an operation condition of the means for performing at least one function based on a result of the self test.

14. The sensing head of claim 13 further comprising user interface means for conveying information to a user, wherein:

the self test means identifies at least one component in the sensing head that is not working properly based on the result of the self test; and

the user interface means indicates that the sensing head is not working properly or conveys information identifying the at least one component that is not working properly.

15. The sensing head of claim 13 further comprising user interface means for conveying information to a user, wherein if the data processing means determines that the means for performing at least one function is working properly, the user interface means conveys information indicating that the sensing head is in a normal operation condition.

16. A sensing head for use in a wheel alignment system for producing data usable in calculating alignment parameters, the sensing head comprising:

a housing for mounting on a wheel of a vehicle to be measured by operation of the wheel alignment system;

a wireless communication module configured to communicate, in a wireless manner, with a remote computer system or a companion sensing head attached to the vehicle, wherein the wireless communication module performs a selection selecting at least one communication path from the following communication paths, for transmitting data to the remote computer;

(1) a first wireless communication path formed between the sensing head and the remote computer system; and

(2) a second wireless communication path including a communication path from the sensing head to the computer system through a companion sensing head mounted on another wheel of the vehicle;

wherein;

a failure that occurs to one of the first wireless communication path and the second wireless communication path does not affect the operation the other communication path.

17. The sensing head of claim 16, wherein:

a command from the computer system is transmitted to the sensing head via at least one of the first wireless communication path and the second wireless communication path.

18. The sensing head of claim 16, wherein:

the wireless communication module includes a first wireless communication module configured to communicate with the computer system in a wireless manner; and

a second wireless communication module configured to communicate with the companion sensing head in a wireless manner.

19. The sensing head of claim 16, wherein the data generated by the sensing head is transmitted to the computer system using both the first wireless communication path and the second wireless communication path.

20. The sensing head of claim 16, wherein:

the data generated by the sensing head is transmitted to the computer system using only one of the first wireless communication path and the second wireless communication path; and

when the one of the wireless communication paths fails, the other one of the wireless communication paths is activated to transmit the data to the computer system.

21. The sensing head of claim 18, wherein:

the second wireless communication module receives data produced by the companion sensing head; and

the first wireless communication module transmits data generated based on the received data to the computer system.

22. The sensing head of claim 18, wherein:

the first wireless communication module receives a command intended for the companion sensing head from the computer system; and

the second wireless communication module transmits signals generated based on the received command, to the companion sensing head.

23. A sensing head for use in a wheel alignment system for producing data usable in calculating alignment parameters, the sensing head comprising:

a housing for mounting on a wheel of a vehicle to be measured by operation of the wheel alignment system;

a drop sensor configured to acquire data related to a drop of the sensing head;

a data storage device, coupled to the drop sensor, configured to store the data acquired by the drop sensor; and

a data processor configured to determine an occurrence of the drop based on the data acquired by the drop sensor.

24. The sensing head of claim 23, wherein the data related to the drop includes at least one of a time duration of the drop and an acceleration value during the drop.