Capacitor array sensors tactile and proximity sensing and methods of use thereof

• US 4,766,389 A
• Filed: 09/03/1986
• Issued: 08/23/1988
• Est. Priority Date: 09/03/1986
• Status: Expired due to Term

• Current Assignee: The ExOne Company (Desktop Metal, Inc.)
• Original Assignee: Extrude Hone Corporation
• Inventors: Rhoades, Lawrence J., Resnick, Ralph L., Risko, Donald
• Primary Examiner(s): Tolin, G. P.
• Assistant Examiner(s): WILLIAMS, HOWARD L
• Application Number:
  US06/903,178
• Time in Patent Office: 720 Days
• Field of Search: 324/61 QS, 324/61 QL, 324/61 R, 324/61 P, 340/870.37, 901/33, 901/46, 901/9, 901/10, 901/34, 901/35, 73/862.04, 73/862.05, 73/862.68, 361/278, 361/280, 361/283, 361/287, 361/290, 414/5, 414/6
• US Class Current: 324/662
• CPC Class Codes: B25J 13/083 fitted with slippage detectors
• CPC Class Codes: B25J 13/084 Tactile sensors in general G01L5/16, G01L5/22
• CPC Class Codes: B25J 13/086 Proximity sensors
• CPC Class Codes: B25J 19/02 Sensing devices
• CPC Class Codes: G01B 7/023 for measuring distance between sensor and object G01B7/082 and G01B7/102 take precedence
• CPC Class Codes: G01D 5/2417 by varying separation
• CPC Class Codes: G01L 1/146 for measuring force distributions, e.g. using force arrays G01L1/148 takes precedence
• CPC Class Codes: G01L 5/228 using tactile array force sensors

Abstract

An arrangement for a tactile sensing system involved in the determination of object shape, contour, orientation and detection of slip finding one use in real time control of robotically manipulated tools. The sensor uses contact between the object and a gripper upon which the sensor is disposed wherein the object surface forms one plate of the sensing electrode.

Claims

1. A capacitance sensor array for proximity and tactile sensing of properties of an object comprising a plurality of capacitor plate elements formed in an array of known topology, means for actively connecting each of said plate elements and said object to one of a plurality of corresponding oscillator circuits so that the oscillation frequency of each said circuit is a function of the capacitance between each said plate element and said object, when said sensor array and said object are in contact, and means for generating an output from said sensor which is a function of the tactile properties of said object from the said plurality of oscillator circuits.

2. The sensor of claim 1 wherein said output from said sensor responds to a changes in the capacitance of said individual capacitor plate elements and is thereby a function of slip between said sensor and said object.

3. The sensor of claim 2 wherein said output is a function of a relative movement between said sensor and said object with a lower limit of about 1000 micrometers.

4. The sensor of claim 2 wherein said output is a function of a relative movement between said sensor and said object with a lower limit of about 100 micrometers.

5. The sensor of claim 2 wherein said output is a function of a relative movement between said sensor and said object with a lower limit of about 2.5 micrometers.

6. The sensor of claim 2 wherein said output detects slip in about 50 milliseconds or less.

7. The sensor of claim 2 wherein said output detects slip in about 30 milliseconds or less.

8. The sensor of claim 2 wherein said output detects slip in about 10 milliseconds or less.

9. A capacitance sensor for detecting relative movement between said sensor and an object capable of detecting movements of about 2.5 micrometers and greater in a time of about 10 milliseconds or less, when said sensor and said object are in contact with one another, comprising means for capacitively coupling said sensor and said object, oscillator means having a frequency rate which is a function of the capacitance between said sensor and said object, and means for generating a output signal which is a measure of slip from a change in the frequency of said oscillator representing a change in capacitance between said sensors and said object.

10. The sensor of claim 9 wherein said output is a plurality of signals corresponding to the oscillation frenquency of each said oscillator.

11. The sensor of claim 10 wherein said output is a continuous parallel output.

12. The sensor of claim 10 wherein said output is a serial output of each of said plurality of oscillators taken in sequence.

13. The sensor of claim 10 wherein said output is a serial plurality of sequential parallel outputs of a plurality of said oscillators.

14. A detector for determining tactile and proximity information concerning an object in contact therewith, comprising a sensor having a plurality of capacitor plate elements formed in an array of known topology and signal processing means for employing said sensor signals resulting from variations in capacitance between the individual capacitor plate elements and said object to determine tactile and proximity information about said object.

15. The detector of claim 14 wherein said signal processing means evaluates the change in capacitance between said detector and said object as a function of the distance between them.

16. The detector of claim 14 wherein said signal processing means evaluates the capcitance signals to detect the shape of said object.

17. The detector of claim 14 wherein said signal processing means evaluates the capacitance signals to detect the orientation of said object.

18. The detector of claim 14 wherein said signal processing means evaluates the capacitance signals to detect the location and orientation of edges of the object.

19. The detector of claim 14 wherein said signal processing means evaluates the capacitance signals to detect a relative movement between the sensor and said object.

20. The detector of claim 14 wherein said signal processing means is employed to generate control signals for a tool which is operatively associated with said object.

21. The detector of claim 20 wherein said control signals are generated as real time controls of said tool.

22. The detector of claim 20 wherein said control signals are real time closed loop feedback control signals.

23. The detector of claim 22 wherein said tool is a robotic gripper which engages and manipulates said object.

24. A capacitance sensor array for tactile sensing of quality control properties of an object comprising a plurality of capacitor plate elements formed in an array of topology conforming to the topology of the design of said object, means for actively connecting each of said plate elements and said object to one of a plurality of corresponding oscillator circuits so that the oscillation frequency of each said circuit is a function of the capacitance between each said plate element and said object, and means for generating an output from said sensor which is a function of the conformity of the shape of said object to the shape of said design topology of said object determined by response of the said plurality of oscillator circuits.