Force controlling system

• US 5,012,591 A
• Filed: 10/25/1989
• Issued: 05/07/1991
• Est. Priority Date: 11/30/1983
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Asakawa, Kazuo
• Primary Examiner(s): Bucci, David A.
• Assistant Examiner(s): Underwood, Donald W.
• Application Number:
  US07/344,389
• Time in Patent Office: 559 Days
• Field of Search: 414/730, 901/9, 901/35, 901/34, 901/41, 33/561, 33/559, 33/558, 33/556, 33/832
• US Class Current: 33/832
• CPC Class Codes: B25J 13/082 Grasping-force detectors in general G01L5/16, G01L5/22
• CPC Class Codes: B25J 15/0246 actuated by an electromagnet
• CPC Class Codes: B25J 15/0253 comprising parallel grippers
• CPC Class Codes: B25J 9/1015 using additional, e.g. microadjustment of the end effector
• CPC Class Codes: G01B 7/02 for measuring length, width or thickness G01B7/004, G01B7/12 take precedence
• CPC Class Codes: G01L 5/226 to manipulators, e.g. the force due to gripping
• CPC Class Codes: Y10S 294/907 Sensor controlled device

Abstract

In a force controlling system, a movable member fixed to an elastic member applies a force in correspondence with a force information signal to an object. At this time, an additional force is applied via a driver to the movable member by the positive feedback of the displacement of the elastic member to the driver, so that the reactive force due to the displacement of the elastic member is contradicted by the additional force. As a result, the movable member applies only a force in correspondence to the force information signal to the object.

Claims

1. A tactile apparatus comprising:

a base element;

a movable member;

an elastic member movably connecting said movable member to said base element;

a contact probe, mounted on said movable member to apply a force corresponding to a predetermined force to an object;

detecting means, provided in said elastic member. for detecting elastic deformation of said elastic member in a displacement direction and for generating a displacement signal responsive to the detected elastic deformation;

driving means for driving said movable member along the displacement direction;

control means, operatively connected to said detecting means and to said driving means, for controlling said driving means by positive feedback of the displacement signal so as to contradict the reactive force due to the displacement of said elastic member applied to the object, and so that said movable member substantially applies only the predetermined force to the object; and

measuring means, operatively connected to said detecting means, for measuring the shape of the object based on the displacement signal.

2. An apparatus as set forth in claim 1, wherein said elastic member comprises leaf spring means.

3. An apparatus as set forth in claim 1, wherein said elastic member comprises parallel-plate springs.

4. An apparatus as set forth in claim 1, wherein said detecting means comprises strain gauge means.

5. An apparatus as set forth in claim 1, wherein said driving means comprises a linear motor.

6. An apparatus as set forth in claim 1, wherein said driving means comprises a voice coil motor.

12. An apparatus as set forth in claim 1, further comprising:

a movable mechanism, fixed to said base member, for moving said base member;

a further driving means for diving said movable mechanism;

a further control means, connected to said further driving means, and to said detecting means, for controlling said further driving means by the negative feedback of said elastic member thereto.

13. A system as set forth in claim 12, further comprising a further detecting means, connected to said further driving means, for detecting the displacement of said movable mechanism,

said measuring means being connected to said further detecting means thereby measuring the shape of said object by the outputs of said detecting means and said further detecting means.

14. A system as set forth in claim 12, wherein said further driving means comprises a DC motor.

7. An apparatus as set forth in claim , wherein said voice coil motor comprises:

a plate-type coil; and

at least two plate-type permanent magnets sandwiching said plate-type coil.

8. An apparatus as set forth in claim 7, wherein said permanent magnets are cobalt magnets.

9. An apparatus as set forth in claim 7, wherein said voice coil motor further comprises a bobbin of aluminum.

10. An apparatus as set forth in claim 9, wherein said bobbin is made by alumite processing.

11. An apparatus as set forth in claim 7, wherein said voice coil motor further comprises nonmagnetic plates having apertures for inserting said plate-type permanent magnets.

15. A robot system comprising:

an arm

a tactile apparatus mounted on the end of said arm, said tactile apparatus comprising;

a base element;

a movable member;

an elastic member movably connecting said movable member to said base element;

a contact probe, mounted on said movable member to apply a force corresponding to a predetermined force to an object;

first detecting means, provided in said elastic member, for detecting the elastic deformation of said elastic member in a displacement direction and for generating a displacement signal responsive to the detected elastic deformation;

first driving means for driving said movable member along the displacement direction

first control means, operatively connected to said detecting means and to said first driving means, for controlling said first driving means by positive feedback of the displacement signal so as to contradict the reactive force due to the displacement of said elastic member applied to the object and so that said movable member substantially applies only the predetermined force to the object;

second driving means for driving said arm;

second control means, operatively connected to said second driving means, and to said first detecting means for controlling said second driving means by negative feedback of the displacement signal.

16. An apparatus as set forth in claim 15, wherein said elastic member comprises leaf spring means.

17. An apparatus as set forth in claim 15, wherein said elastic member comprises parallel-plate springs.

18. An apparatus as set forth in claim 15, wherein said detecting means comprises strain gauge means.

19. An apparatus as set forth in claim 15, wherein said first driving means comprises a linear motor.

20. An apparatus as set forth in claim 15, wherein said first driving means comprises a voice coil motor.

21. An apparatus as set forth in claim 15, wherein said voice coil motor comprises:

a plate-type coil; and

at least two plate-type permanent magnets sandwiching said plate-type coil.

22. An apparatus as set forth in claim 21, wherein said permanent magnets are cobalt magnets.

23. An apparatus as set forth in claim 21, wherein said voice coil motor further comprises a bobbin of aluminum.

24. An apparatus as set forth in claim 23, wherein said bobbin of aluminum is made by alumite processing.

25. An apparatus as set forth in claim 21, wherein said voice coil motor further comprises nonmagnetic plates having apertures for inserting said plate-type permanent magnets.

26. A system as set forth in claim 15, wherein said second driving means comprises a DC motor.