Control circuit for sensor array and related methods

• US 7,591,165 B2
• Filed: 03/29/2006
• Issued: 09/22/2009
• Est. Priority Date: 03/29/2006
• Status: Active Grant

• Current Assignee: Tekscan, Inc.
• Original Assignee: Tekscan, Inc.
• Inventors: Malacaria, Charles, Dubinsky, Boris, Papakostas, Thomas
• Primary Examiner(s): Rogers; David A.
• Application Number:
  US11/392,210
• Publication Number:
  US 20070234825A1
• Time in Patent Office: 1,273 Days
• Field of Search: 73/15.7, 73/15.9, 73/16.1, 73/16.2, 736/14, 736/15, 736/16, 324/614, 324/615, 324/616, 702/99, 702/100, 702/104
• US Class Current: 73/1.59
• CPC Class Codes: G01L 1/205 using distributed sensing elements
• CPC Class Codes: G01L 25/00 Testing or calibrating of apparatus for measuring force, torque, work, mechanical power, or mechanical efficiency
• CPC Class Codes: G01L 27/002 Calibrating, i.e. establishing true relation between transducer output value and value to be measured, zeroing, linearising or span error determination

Abstract

A control circuit for scanning a pressure or force responsive sensor array is disclosed. Pressure or force sensors formed of an array of pressure or force responsive sensor elements can be used to acquire pressure or force measurements in response to an applied load. The control circuit can sample signals from the sensor elements to detect the pressure or force at one or more sensor elements of the sensor array. The circuit herein may provide for relatively faster scan rates. A user may define a subset or subsets of sensor elements of the sensor array to be scanned. Various methods and related circuitry for adjusting for sensor characteristics are also disclosed.

Claims

1. A method of automatically adjusting gain when scanning an array of pressure or force responsive sensor elements, the method comprising:

(A) detecting a frame of received signals corresponding to a plurality of sensor elements of the array being scanned;

(B) determining a signal strength value at least partially based on the frame of received signals, the signal strength value comprising a count of a number of the received signals of the frame that are greater than a threshold signal value; and

(C) adjusting a gain applied to at least some signals received from the array based at least partially on the signal strength value.

2. The method of claim 1, wherein (C) comprises decreasing the gain applied to at least some signals received from the array as a result of the signal strength value being greater than an upper limit.

3. The method of claim 1, wherein (C) comprises increasing the gain applied to at least some signals received from the array as a result of the signal strength value being less than a lower limit.

4. The method of claim 1, wherein the frame of received signals is a first frame of received signals, and wherein (C) comprises adjusting a gain applied to at least some signals of a second frame of received signals.

5. A method of automatically adjusting gain when scanning an array of pressure or force responsive sensor elements, the method comprising:

(A) detecting a frame of received signals corresponding to a plurality of sensor elements of the array being scanned;

(B) determining a signal strength value at least partially based on the frame of received signals, wherein the signal strength value comprises an average received signal of the frame of received signals; and

(C) adjusting a gain applied to at least some signals received from the array based at least partially on the signal strength value.

6. The method of claim 5, wherein the frame of received signals is a first frame of received signals, and wherein (C) comprises adjusting a gain applied to at least some signals of a second frame of received signals.

7. The method of claim 5, wherein (C) comprises decreasing the gain applied to at least some signals received from the array as a result of the signal strength value being greater than an upper limit.

8. The method of claim 5, wherein (C) comprises increasing the gain applied to at least some signals received from the array as a result of the signal strength value being less than a lower limit.

9. A method of calibrating a sensitivity of a sensor array of pressure or force responsive sensor elements, each of the sensor elements being connected by one of one or more first electrodes and one of one or more second electrodes, the sensor elements having signals generated therethrough, the signals being characteristic of a pressure or force applied to the sensor array, the one or more second electrodes having received signals thereon associated with the sensor elements, the received signals being modified by a gain value, the method comprising:

(A) obtaining received signals associated with at least some of the sensor elements; and

(B) determining the gain value that modifies the received signals associated with the at least some of the sensor elements so that at least some of the received signals associated with the at least some of the sensor elements lie within a desired range,

wherein (B) comprises;

determining an average received signal of the received signals associated with the at least some of the sensor elements; and

determining the gain value that modifies the received signals associated with the at least some of the sensor elements so that the average received signal lies within the desired range,

wherein the desired range comprises a saturation point of the average received signal.

10. The method of claim 9, wherein the determined gain value is stored as calibration data associated with the sensor array.

11. The method of claim 9, wherein the saturation point of the average received signal is an upper limit of the desired range.

12. The method of claim 9, wherein determining the gain value that modifies the received signals associated with the at least some of the sensor elements so that the average received signal lies within a desired range comprises determining the gain value that modifies the received signals associated with the at least some of the sensor elements so that the average received signal is approximately equal to the saturation point of the average received signal.

13. The method of claim 9, wherein determining the gain value that modifies the received signals associated with the at least some of the sensor elements so that the average received signal lies within a desired range comprises determining the gain value that modifies the received signals associated with the at least some of the sensor elements so that the average received signal is less than the saturation point of the average received signal.

14. A method of calibrating a sensitivity of a sensor array of pressure or force responsive sensor elements, each of the sensor elements being connected by one of one or more first electrodes and one of one or more second electrodes, the sensor elements having signals generated therethrough, the signals being characteristic of a pressure or force applied to the sensor array, the one or more second electrodes having received signals thereon associated with the sensor elements, the received signals being modified by a gain value, the method comprising:

(A) obtaining received signals associated with at least some of the sensor elements; and

(B) determining the gain value that modifies the received signals associated with the at least some of the sensor elements so that at least some of the received signals associated with the at least some of the sensor elements lie within a desired range,

wherein the desired range comprises a saturation point of the at least some of the received signals.

15. The method of claim 14, wherein the determined gain value is stored as calibration data associated with the sensor array.

16. The method of claim 14, wherein the saturation point of the at least some of the received signals is an upper limit of the desired range.

17. The method of claim 14, wherein determining the gain value that modifies the received signals associated with the at least some of the sensor elements so that at least some of the received signals associated with the at least some of the sensor elements lie within a desired range comprises determining the gain value that modifies the received signals associated with the at least some of the sensor elements so that at least some of the received signals associated with the at least some of the sensor elements are less than the saturation point of the at least some of the received signals.