Magneto-inductive sensor for performing tactile and proximity sensing

• US 4,950,987 A
• Filed: 03/03/1989
• Issued: 08/21/1990
• Est. Priority Date: 03/03/1989
• Status: Expired due to Fees

• Current Assignee: University of North Carolina Charlotte UNCC Station
• Original Assignee: University of North Carolina At Charlotte (University of North Carolina System)
• Inventors: Vranish, John M., Yadav, Pradeep K.
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Snow, Walter E.
• Application Number:
  US07/319,411
• Time in Patent Office: 536 Days
• Field of Search: 324/207, 324/208, 324/226, 324/227, 324/262, 901/10, 901/30, 901/33, 901/35, 901/46
• US Class Current: 324/207.23
• CPC Class Codes: G01B 7/023 for measuring distance between sensor and object G01B7/082 and G01B7/102 take precedence

Abstract

The present invention discloses a single sensor performing both tactile and proximity sensing. The sensor includes a magnetic field generator, a magnetic field sensor for sensing changes in the magnetic field in response to an object changing position with respect to the field to provide proximity sensing. By providing for relative movement between the response to the object touching the sensor, tactile sensing is provided.

Claims

1. A proximity and tactile sensor for sensing an object, comprising:

magnetic field generating means;

magnetic field proximity and tactile sensing means positioned within said magnetic field for sensing changes in the magnetic field generated by said magnetic field generating means in response to said object changing position within said magnetic field to provide proximity sensing; and

means mounting said magnetic field generating means and said magnetic field proximity and tactile sensing means for relative movement in response to said object moving at least a portion of said sensor, whereby said magnetic field proximity and tactile sensing means senses a change in the magnetic field in response to said relative movement to provide tactile sensing.

2. The sensor of claim 1 wherein said magnetic field generating means is a solenoid.

3. The sensor of claim 1 wherein said solenoid comprises a core and winding therearound and means for providing an electric current in said winding.

4. The sensor of claim 3 wherein said core comprises a hollow, nonmagnetic cylinder.

5. The sensor of claim 3 wherein said means for providing an electric current comprises means for providing sinusoidal electric current in said winding.

6. The sensor of claim 1 wherein said magnetic field proximity and tactile sensing means comprises a sensor coil for producing an induced voltage as a function of the magnetic field around said coil.

7. The sensor of claim 1 wherein said magnetic field proximity and tactile sensing means is an inductor.

8. The sensor of claim 7 wherein said inductor comprises a core and a winding for producing an induced voltage.

9. The sensor of claim 8 further comprising means for detecting the voltage in said winding to provide proximity and tactile sensing signals.

10. The sensor of claim 1 wherein said mounting means comprises a resilient member between said magnetic field generating means and said magnetic field proximity and tactile sensing means.

11. The sensor of claim 1 wherein said magnetic field generating means comprises a solenoid, wherein said magnetic field sensing means comprises an inductor, and wherein said mounting means comprises a compressible insulating ring between said inductor and said solenoid.

12. The sensor of claim 1 wherein said magnetic field proximity and tactile sensing means comprises a winding mounted adjacent said magnetic field generating means, and wherein said mounting means comprises compressible insulation on said winding.

13. A robotic system comprising:

a robot;

an array of single magneto-inductive sensing means carried by said robot, each of said single sensing means providing both tactile and proximity sensing;

means in said single magneto-inductive sensing means for generating a signal in response to a nearby object; and

means responsive to said signal for controlling said robot.

14. The robotic system of claim 13 wherein said single sensing means comprises:

a non-magnetic conductive base;

a sensor core element;

a sensor winding surrounding said sensor core element;

insulating means positioned between said conductive base and said sensor winding;

a primary winding surrounding one of said insulating means and said conductive base, said primary winding for carrying an electric current;

whereby said electric current in said primary winding produces a magnetic field which results in generation of said signal.

15. The robotic system of claim 14 wherein said array of single magneto-inductive sensing means is located on a movable arm of said robot.

16. The robotic system of claim 14 wherein said sensor windings are coated with a thin coating of insulation.

17. The robotic system of claim 14 wherein said insulating means comprises a compressible insulator.

18. A sensing apparatus performing both tactile and proximity sensing, comprising:

a base;

a proximity and tactile sensor element;

a sensor winding surrounding said tactile and proximity sensor element;

insulating means positioned between said base and said proximity and tacticle sensor element; and

a primary winding surrounding one of said insulator and said base, said primary winding for carrying an electric current

to generate a magnetic field inside and outside said sensing apparatus, to thereby produce a proximity and tactile strength signal in said sensor winding.

19. The sensor apparatus of claim 18 wherein said sensor element comprises a magnetic core.

20. The sensor apparatus of claim 18 wherein said sensor apparatus is located on a movable arm of a robot.

21. The sensor apparatus of claim 18 wherein said sensor winding is coated with a thin coating of insulation.

22. The sensor apparatus of claim 21 wherein said insulation comprises compressible insulation.

23. Apparatus for sensing both the approach of an object and contact of the object with the apparatus and comprising a single magneto-inductive sensor element means for generating a first signal in response to said object approaching said apparatus and for generating a second signal in response to said object moving at least a portion of said apparatus.

24. The apparatus of claim 23 wherein said single magneto-inductive sensor element comprises a single electromagnetic element.

25. The apparatus of claim 24 wherein said single electromagnetic element comprises a coil.

26. The apparatus of claim 24 further comprising means for generating an electromagnetic field outside said apparatus.

27. A proximity and tactile sensor for sensing an object, comprising:

magnetic field generating means;

magnetic field sensing means positioned within said magnetic field for sensing changes in the magnetic field generated by said magnetic field generating means in response to said object changing position within said magnetic field to provide proximity sensing; and

means mounting said magnetic field generating means and said magnetic field proximity and tactile sensing means for relative movement in response to said object moving at least a portion of said sensor, whereby said magnetic field proximity and tactile sensing means senses a change in the magnetic field in response to said relative movement to provide tactile sensing;

wherein said magnetic field generating means comprises a solenoid having a core and winding therearound and means for providing an electric current in said winding; and

wherein said core comprises a hollow nonmagnetic cylinder.

28. A proximity and tactile sensor for sensing an object, comprising:

magnetic field generating means;

magnetic field sensing means positioned within said magnetic field for sensing changes in the magnetic field generated by said magnetic field generating means in response to said object changing position within said magnetic field to provide proximity sensing; and

means mounting said magnetic field generating means and said magnetic field sensing means for relative movement in response to said object moving at least a portion of said sensor, whereby said magnetic field proximity and tactile sensing means senses a change in the magnetic field in response to said relative movement to provide tactile sensing;

wherein said magnetic field sensing means comprises an inductor and having a core and a winding for producing an induced voltage;

said proximity and tactile sensor further comprising means for detecting the voltage in said winding to provide proximity and tactile sensing signals.

29. A proximity and tactile sensor for sensing an object, comprising:

magnetic field generating means;

magnetic field sensing means positioned within said magnetic field for sensing changes in the magnetic field generated by said magnetic field generating means in response to said object changing position within said magnetic field to provide proximity sensing;

means mounting said magnetic field generating means and said magnetic field sensing means for relative movement in response to said object moving at least a portion of said sensor, whereby said magnetic field proximity and tactile sensing means senses a change in the magnetic field in response to said relative movement to provide tactile sensing; and

wherein said magnetic field generating means comprises a solenoid, wherein said magnetic field sensing means comprises an inductor, and wherein said mounting means comprises a compressible insulating ring between said inductor and said solenoid.

30. A robotic system comprising:

a robot;

an array of single sensing means carried by said robot, each of said single sensing means providing both tactile and proximity sensing;

means in said single sensing means for generating a single in response to a nearby object; and

means responsive to said signal for controlling said robot;

each of said single sensing means comprising;

a non-magnetic conductive base;

a sensor core element;

a sensor winding surrounding said sensor core element;

insulating means positioned between said conductive base and said sensor winding; and

a primary winding surrounding one of said insuating means and said conductive base, said primary winding for carrying an electric current;

whereby said electric current in said primary winding produces a magnetic field which results in generation of said signal.

31. The robotic system of claim 30 wherein said array of single sensing means is located on a movable arm of said robot.

32. The robotic system of claim 30 wherein said sensor windings are coated with a thin coating of insulation.

33. The robotic system of claim 30 wherein said insulating means comprises a compressible insulator.

34. Apparatus for sensing both the approach of an object and contact of the object with the apparatus and comprising a single sensor element means for generating a first signal in response to said object approaching said apparatus and for generating a second signal in response to said object moving at least a portion of said apparatus;

wherein said single sensor element comprises a single electromagnetic coil.