Force controlling system

• US 4,872,803 A
• Filed: 03/29/1988
• Issued: 10/10/1989
• 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): Spar, Robert J.
• Assistant Examiner(s): Underwood, Donald W.
• Application Number:
  US07/175,616
• Time in Patent Office: 560 Days
• Field of Search: 901/38, 901/34, 901/32, 901/31, 414/730, 414/744.2, 318/687, 318/646, 294/99.1, 294/103.1, 294/907, 294/88, 294/86.4, 294/119.1, 93/517 B
• US Class Current: 414/730
• 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 to an object in correspondence with a force reference signal. 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 counteracted by the additional force. As a result, the movable memer applies only a force in correspondence to the force reference signal to the object.

Claims

1. A force generating apparatus for applying a force to an object by receiving a force information signal, comprising:

a base member;

an elastic member fixed to said base member and producing a reactive force when it is displaced;

a movable member, fixed to said elastic member, for applying said force corresponding to said force information signal to said object;

detecting means, provided on said elastic member, for detecting the displacement thereof, so that said detecting means generates a displacement signal corresponding to the displacement;

driving means for driving said movable member, comprising a linear motor having a stator side fixed to said base member and a movable side fixed to said movable member; and

control means, connected to said detecting means and to said driving means for controlling said driving means by said force information signal to move said movable member along a displacement direction, thereby applying a force to said object, and for controlling said driving means by said displacement signal to move said movable member along said displacement direction, thereby counteracting said reactive force of said elastic member, wherein said reactive force is counteracted and said movable member applies only a force corresponding to said force information signal to said object.

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 moving coil motor.

6. An apparatus as set forth in claim 5, wherein said moving coil motor comprises:

a plate-type coil; and

at least one plate-type permanent magnet located in the vicinity of said plate-type coil.

7. An apparatus as set forth in claim 6, wherein said permanent magnets are cobalt magnets.

8. An apparatus as set forth in claim 6, wherein said moving coil motor further comprises a bobbin of aluminum.

9. An apparatus as set forth in claim 8, wherein said bobbin of aluminum is made by alumite processing.

10. An apparatus as set forth in claim 6, wherein said moving coil motor further comprises at least one nonmagnetic plate having a respective aperture for inserting each said plate-type permanent magnet.

11. An object processing system having a movable mechanism and receiving a predetermined force information signal, comprising:

a force generating apparatus mounted on said movable mechanism, said force generating apparatus comprising;

a base member;

an elastic member attached to said base member and producing a reactive force when it is displaced;

a movable member, attached to said elastic member, applying a force corresponding to said force information signal to an object;

first detecting means, provided on said elastic member, for detecting the displacement of said elastic member, so that said detecting means generates a displacement signal corresponding to the displacement; and

first driving means for driving said movable member, comprising a linear motor having a stator side fixed to said base member and a movable side fixed to said movable member;

first control means, connected to said first detecting means and to said first driving means, for controlling said first driving means by said force information signal to move said movable member along a displacement direction, thereby applying a force to said object, and for controlling said driving means by said displacement signal to move said movable member along said displacement direction, counteracting said reactive force of said elastic member and applying through said movable member substantially only the force corresponding to said force information signal to said object;

means for applying said force information signal to said first control means;

second driving means for driving said movable mechanism; and

second control means, connected to said second driving means, for controlling said second driving means.

12. A system as set forth in claim 11, comprising:

second detecting means, connected to said second driving means, for detecting the displacement of said movable mechanism;

wherein said second control means receives an externally supplied position indication signal and a position detecting signal from said second detecting means, and controls said second driving means so that said position detecting signal coincides with said position indication signal.

13. A system as set forth in claim 11, wherein said second control means is connected to said first detecting means, and controls said second driving means by negative feedback of the displacement of said elastic member.

14. A system as set forth in claim 11, wherein said elastic member comprises leaf spring means.

15. A system as set forth in claim 11, wherein said elastic member comprises parallel-plate springs.

16. A system as set forth in claim 11, wherein said first detecting means comprises strain gauge means.

17. A system as set forth in claim 11, wherein said first driving means comprises a moving coil motor.

18. A system as set forth in claim 11, wherein said moving coil motor comprises;

a plate-type coil; and

at least one plate-type permanent magnet located in the vicinity of said plate-type coil.

19. A system as set forth in claim 18, wherein said permanent magnets are cobalt magnets.

20. A system as set forth in claim 18, wherein said moving coil motor further comprises a bobbin of aluminum.

21. A system as set forth in claim 20, wherein said bobbin of aluminum is made by alumite processing.

22. A system as set forth in claim 18, wherein said moving coil motor comprises at least one non-magnetic plate having a respective aperture for inserting each said plate-type perment magnet.

23. A system as set forth in claim 11, wherein said movable mechanism comprises a feed screw on which said force generating apparatus is mounted.

24. A system as set forth in claim 23, wherein said movable mechanism comprises at least one nut, mounted on said feed screw, for adjusting said force generating apparatus.

25. A system as set forth in claim 24, wherein said movable mechanism comprises a further elastic member inserted between said force generating apparatus and said nut.

26. A system as set forth in claim 11, wherein said second driving means comprises a DC motor.

27. A robot system including means for providing a force information signal, comprising:

an arm;

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

a base member;

an elastic member attached to said base member;

a movable member, attached to said elastic member, applying a force corresponding to said force information signal to an object;

first detecting means provided in said elastic member, for detecting the displacement of said elastic member, so that said first detecting means generates a displacement signal corresponding to the displacement; and

first driving means for driving said movable member, comprising a linear motor having a stator side fixed to said base member and a movable side fixed to said movable member;

first control means, connected to said detecting means and to said first driving means, for controlling said first driving means by said force information signal, to move said movable member along a displacement direction thereby applying a force to said object, and for controlling said driving means by said displacement signal to move said movable member along said displacement direction, counteracting said reactive force counteracted and applying through said movable member substantially only a force corresponding to said force information signal to said object;

second driving means for driving said arm; and

second control means, connected to said second driving means, for controlling said second driving means.

28. A system as set forth in claim 27, comprising:

second detecting means, connected to said second driving means, for detecting the displacement of said arm;

wherein said second control means receives a position indication signal and a position detecting signal from said second detecting means, and controls said second driving means so that said position detecting signal coincides with said position indication signal.

29. A system as set forth in claim 27, wherein said second control means is connected to said first detecting means, and controls said second driving means by negative feedback of said displacement of said elastic member.

30. A system as set forth in claim 27, wherein said elastic member comprises leaf spring means.

31. A system as set forth in claim 27, wherein said elastic member comprises parallel-plate springs.

32. A system as set forth in claim 27, wherein said first detecting means comprises strain gauge means.

33. A system as set forth in claim 27, wherein said first driving means comprises a moving coil motor.

34. An apparatus as set forth in claim 33, wherein said moving coil motor comprises:

a plate-type coil; and

at least one plate-type permanent magnet located in the vicinity of said plate-type coil.

35. A system as set forth in claim 34, wherein said permanent magnets are cobalt magnets.

36. A system as set forth in claim 34, wherein said moving coil motor further comprises a bobbin of aluminum.

37. A system as set forth in claim 36, wherein said bobbin of aluminum is made by alumite processing.

38. An apparatus as set forth in claim 27, wherein said moving coil motor further comprises a non-magnetic plate having a respective aperture for inserting each said plate-type permanent magnet.

39. A system as set forth in claim 27, wherein said arm comprises a feed screw on which said force generating apparatus is mounted.

40. A system as set forth in claim 39, wherein said arm further comprises a nut, mounted on said feed screw, for adjusting said force generating apparatus.

41. A system as set forth in claim 40, wherein said arm comprises a further elastic member inserted between said force generating apparatus and said nut.

42. A system as set forth in claim 27, wherein said second driving means comprises a DC motor.

43. A system as set forth in claim 27, wherein said force generating apparatus generates forces in two dimensions.

44. A system as set forth in claim 27, wherein said force generating apparatus generates forces in three dimensions.

45. A gripping apparatus for gripping an object, said gripping apparatus comprising:

two fingers for applying force to said object by gripping said object between said two fingers, at least one of said two fingers including a base member, elastic member, movable member, detecting means and driving means, said elastic member being attached to said base member and producing a reactive force when it is displaced, said movable member being attached to said elastic member and applying a force corresponding to said force information signal to said object, and said detecting means being provided in said elastic member, and for detecting the displacement of said elastic member, so that said detecting means generates a displacement signal corresponding to the displacement; and

said driving means for driving said movable member, comprising a linear motor having a stator side fixed to said base member and a movable side fixed to said movable member; and

control means, connected to said detecting means and to said driving means, for controlling said driving means by said force information signal to move said movable member along a displacement direction thereby applying a force to said object, and for controlling said driving means by said displacement signal to move said movable member along said displacement direction, counteracting said reactive force and applying through said movable member substantially only the force corresponding to said force information signal to said object.

46. An apparatus as set forth in claim 45, wherein said elastic member comprises leaf spring means.

47. An apparatus as set forth in claim 45, wherein said elastic member comprises parallel-plate springs.

48. An apparatus as set forth in claim 45, wherein said detecting means comprises strain gauge means.

49. An apparatus as set forth in claim 45, wherein said driving means comprises a moving coil motor.

50. An apparatus as set forth in claim 49, wherein said moving coil motor comprises:

a plate-type coil; and

at least one plate-type permanent magnet located in the vicinity of said plate-type coil.

51. An apparatus as set forth in claim 50, wherein said permanent magnets are cobalt magnets.

52. An apparatus as set forth in claim 50, wherein said moving coil motor further comprises a bobbin of aluminum.

53. An apparatus as set forth in claim 52, wherein said bobbin of aluminum is made by alumite processing.

54. An apparatus as set forth in claim 50, wherein said moving coil motor further comprises a non-magnetic plate having a respective for inserting each said plate-type permanent magnet.

55. An object processing system, comprising:

means for providing a force information signal;

a movable mechanism having a gripping apparatus, including two fingers, mounted thereon, at least one of the two fingers including;

a base member;

an elastic member attached to said base member and producing a reactive force when it is displaced;

a movable member, attached to said elastic member, applying a force corresponding to said force information signal to an object;

first detecting means, provided in said elastic member, for detecting the displacement of said elastic member so that said first detecting means generates a displacement signal corresponding to the displacement; and

first driving means for driving said movable member, comprising a linear motor having a stator side fixed to said base member and a movable side fixed to said movable member;

first control means, connected to said first detecting means and to said first driving means, for controlling said first driving means by said force information signal to move said movable member along a displacement direction, thereby applying a force to said object, and for controlling said driving means by said displacement signal to move said movable member along said displacement direction, counteracting said reactive force and applying through said movable member substantially only force corresponding to said force information signal to said object;

second driving means for driving said movable mechanism; and

second control means, connected to said second driving means, for controlling said second driving means.

56. A system as set forth in claim 55, further comprising second detecting means, connected to said second driving means, for detecting the displacement of said movable mechanism, said second control means receiving an externally supplied position indication signal and a position detecting signal from said second detecting means, and controlling said second driving means so that said position detecting signal coincides with said position indication signal.

57. A system as set forth in claim 55, wherein said second control means is connected to said first detecting means, and controls said second driving means by negative feedback of the displacement of said elastic member.

58. A system as set forth in claim 55, wherein said elastic member comprises leaf spring means.

59. A system as set forth in claim 55, wherein said elastic member comprises parallel-plate springs.

60. A system as set forth in claim 55, wherein said first detecting means comprises strain gauge means.

61. A system as set forth in claim 55, wherein said first driving means comprises a moving coil motor.

62. A system as set forth in claim 61, wherein said moving coil motor comprises:

a plate-type coil; and

at least one plate-type permanent magnet located in the vicinity of said plate-type coil.

63. A system as set forth in claim 62, wherein said permanent magnets are cobalt magnets.

64. A system as set forth in claim 62, wherein said moving coil motor further comprises a bobbin of aluminum.

65. A system as set forth in claim 64, wherein said bobbin of aluminum is made by alumite processing.

66. A system as set forth in claim 62, wherein said moving coil motor further comprises non-magnetic plates having apertures for inserting said plate-type permanent magnets.

67. A system as set forth in claim 55, wherein said movable mechanism comprises a feed screw on which said base member is mounted.

68. A system as set forth in claim 67, wherein said movable mechanism further comprises a nut, mounted on said feed screw, for adjusting said base member.

69. A system as set forth in claim 68, wherein said movable mechanism comprises a further elastic member inserted between said base member and said nut.

70. A system as set forth in claim 55, wherein said movable mechanism comprises a feed screw having a left-hand screw portion and a right-handed screw portion, on one of which portions said base member is mounted, the other portion being mounted on the other finger.

71. A system as set forth in claim 70, wherein said movable mechanism further comprises two nuts, mounted on said feed screw, for adjusting said base member and the other finger.

72. A system as set forth in claim 71, wherein said movable mechanism comprises tow further elastic members inserted respectively between said base member and the other finger, and the respective one of said nuts.

73. A system as set forth in claim 55, wherein said second driving means comprises a DC motor.

74. A robot system comprising:

means for providing a force information signal;

an arm having a gripping apparatus including two fingers, mounted thereon, at least one of the two fingers including;

a base member;

an elastic member attached to said base member and producing a reactive force when it is displaced;

a movable member, attached to said elastic member, applying a force corresponding to an externally supplied force information signal to an object;

first detecting means, provided in said elastic member, for detecting the displacement of said elastic member, so that said first detecting means generates a displacement signal corresponding to the displacement; and

first driving means for driving said movable member, comprising a linear motor having a stator side fixed to said base member and a movable side fixed to said movable member;

first control means, connected to said first detecting means and to said first driving means, for controlling said first driving means by said force information signal to move said movable member along a displacement direction, thereby applying a force to said object, and for controlling said driving means by said displacement signal to move said movable member along said displacement direction, counteracting said reactive force and applying through said movable member substantially only said force corresponding to said force information signal to said object;

second driving means for driving said movable mechanism; and

second control means, connected to said second driving means, for controlling said second driving means.

75. A system as set forth in claim 74, further comprising:

second detecting means, connected to said second driving means, for detecting the displacement of said arm,

wherein said second control means receives a position indication signal and a position detecting signal from said second detecting means, and controls said second driving means so that said position detecting signal coincides with said position indication signal.

76. A system as set forth in claim 74, wherein said second control means is connected to said first detecting means, and controls said second driving means by negative feedback of said displacement of said elastic member.

77. A system as set forth in claim 74, wherein said elastic member comprises leaf spring means.

78. A system as set forth in claim 74, wherein said elastic member comprises parallel-plate springs.

79. A system as set forth in claim 74, wherein said first detecting means comprises strain gauge means.

80. A system as set forth in claim 74, wherein said first driving means comprises a moving coil motor.

81. A system as set forth in claim 80, wherein said moving coil motor comprises:

a plate-type coil; and

at least one plate-type permanent magnet located in the vicinity of said plate-type coil.

82. A system as set forth in claim 81, wherein said permanent magnets are cobalt magnets.

83. A system as set forth in claim 81, wherein said moving coil motor further comprises a bobbin of aluminum.

84. A system as set forth in claim 83, wherein said bobbin of aluminum is made by alumite processing.

85. A system as set forth in claim 83, wherein said moving coil motor further comprises non-magnetic plates having apertures for inserting said plate-type permanent magnets.

86. A system as set forth in claim 74, wherein said arm comprises a feed screw on which said base member is mounted.

87. A system as set forth in claim 86, wherein said arm comprises a nut, mounted on said feed screw, for adjusting said base member.

88. A system as set forth in claim 87, wherein said arm comprises a further elastic member inserted between said base member and said nut.

89. A system as set forth in claim 74, wherein said arm comprises a feed screw having a left-hand screw portion and a right-hand screw portion, on one of which portions said base member is mounted, the other finger being mounted on the other mounting portion.

90. A system as set forth in claim 89, comprising two nuts, mounted on said feed screw, for adjusting said movable member and the other finger.

91. A system as set forth in claim 90, wherein said arm comprises two further elastic members each inserted between a respective one of said base member and the other finger, and the respective one of said nuts.

92. A system as set forth in claim 74, wherein said second driving means comprises a DC motor.