Sensor assembly

• US 20030074966A1
• Filed: 10/09/2002
• Published: 04/24/2003
• Est. Priority Date: 10/09/2001
• Status: Active Grant

• Current Assignee: Continental Automotive Systems, Inc. (Continental AG)
• Original Assignee: Siemens VDO Automotive Corporation (Siemens AG)
• Inventors: Fukumura, Tomohiro, Dash, Sanjaya Kumar
• Granted Patent: US 7,127,369 B2
• Time in Patent Office: Days
• US Class Current: 73/488
• CPC Class Codes: G01D 2205/85 Determining the direction of movement of an encoder, e.g. of an incremental encoder
• CPC Class Codes: G01D 5/24476 Signal processing G01D5/2448 - G01D5/24495 take precedence
• CPC Class Codes: G01P 13/04 Indicating positive or negative direction of a linear movement or clockwise or anti-clockwise direction of a rotational movement
• CPC Class Codes: G07C 2009/00793 by Hertzian waves
• CPC Class Codes: G07C 2209/63 Comprising locating means for detecting the position of the data carrier, i.e. within the vehicle or within a certain distance from the vehicle

Abstract

A system with a sensor assembly is used to determine direction of movement of an object so that accuracy of position calculation is improved. The sensor assembly measures at least two operational characteristics and generates corresponding operational characteristic signals. A control unit monitors and compares transitions of the signals to more accurately determine direction of movement for the object.

Claims

1. A method for determining a direction in which an object is moving comprising the steps of:

(a) generating a first signal representing a first operational characteristic;

(b) generating a second signal representing a second operational characteristic;

(c) comparing the first and second signals to determine an initial direction; and

(d) monitoring transitions of the first and second signals over time to verify that the initial direction is accurate.

2. A method as set forth in claim 1 including the step of comparing an object speed to a predetermined threshold speed during step (d) to determine whether the initial direction is accurate.

3. A method as set forth in claim 1 wherein step (c) further includes comparing transitions of the first and second signals over time to determine the initial direction and storing the initial direction in memory as a direction history.

4. A method as set forth in claim 3 further including the steps of subsequently checking direction to generate a new direction, comparing the new direction to the initial direction, and checking speed if the new direction is different than the initial direction.

5. A method as set forth in claim 4 further including the step of discarding the new direction if the speed is more than a predetermined threshold speed or speed is increasing.

6. A method as set forth in claim 1 including the steps of measuring speed and changes in speed, comparing speed to a predetermined threshold speed, and only checking direction if the speed is less than the predetermined threshold speed.

7. A method as set forth in claim 6 including the step of assuming no direction change if the speed is more than the predetermined threshold speed or is increasing.

8. A method as set forth in claim 1 including the steps measuring speed and changes in speed, comparing speed to a predetermined threshold speed, and only checking direction if the speed is decreasing.

9. A method as set forth in claim 1 including the steps of measuring speed and changes in speed, comparing speed to a predetermined threshold speed, and only checking direction if the speed is decreasing and is less than the predetermined threshold speed.

10. A method as set forth in claim 1 wherein the moving object comprises a door panel.

11. A method as set forth in claim 1 wherein the moving object comprises a power window.

12. A method as set forth in claim 1 wherein the moving object comprises a vehicle wheel.

13. A method as set forth in claim 1 wherein the moving object comprises a steering wheel.

14. A system for verifying direction of movement of an object in response to an intermittent sensor phase shift comprising:

a sensor assembly for measuring at least first and second object operational characteristics as said object moves to generate first and second object operational characteristic signals; and

a control unit for comparing signal transitions of said first and second object operational characteristic signals to determine an initial direction of object movement and continuing to compare signal transitions of said first and second object operational characteristic signals over time to verify accuracy of initial direction determination.

15. A system as set forth in claim 14 wherein said control unit subsequently checks direction to generate a new direction, compares the new direction to said initial direction, checks speed if the new direction is different than said initial direction, and discards the new direction if the speed is more than a predetermined threshold speed.

16. A system as set forth in claim 14 wherein said control unit only checks direction if speed is less than a predetermined threshold speed.

17. A system as set forth in claim 14 wherein said control unit only checks direction if speed is decreasing.

18. A system as set forth in claim 14 wherein said control unit only checks direction if speed is decreasing and less than a predetermined threshold speed.

19. A system as set forth in claim 14 wherein said control unit assumes no direction change if speed is more than a predetermined threshold speed or is increasing.

20. A system as set forth in claim 14 wherein said object comprises a vehicle door controlled by a power closure system.

21. A system as set forth in claim 14 wherein said object comprises a steering wheel.

22. A system as set forth in claim 14 wherein said object comprises a power window.

23. A system as set forth in claim 14 wherein said object comprises a vehicle wheel and said sensor assembly comprises an ABS wheel sensor.