Six axis force feedback input device

• US 5,828,813 A
• Filed: 10/23/1996
• Issued: 10/27/1998
• Est. Priority Date: 09/07/1995
• Status: Expired due to Term

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Ohm, Timothy
• Primary Examiner(s): Davis, George B.
• Application Number:
  US08/734,966
• Time in Patent Office: 734 Days
• Field of Search: 395/95, 901/28
• US Class Current: 700/260
• CPC Class Codes: A61B 2034/742 Joysticks
• CPC Class Codes: A61B 34/30 Surgical robots
• CPC Class Codes: A61B 34/35 for telesurgery
• CPC Class Codes: A61B 34/37 Master-slave robots A61B34/35 takes precedence
• CPC Class Codes: A61B 34/71 Manipulators operated by drive cable mechanisms
• CPC Class Codes: A61B 34/74 Manipulators with manual electric input means
• CPC Class Codes: A61B 34/77 Manipulators with motion or force scaling
• CPC Class Codes: B25J 13/02 Hand grip control means handles or pedals for crane control B66C13/56; for measuring the force applied to control members G01L5/22; hand-held casings for switching devices, e.g. joy-sticks H01H9/0214
• CPC Class Codes: B25J 17/0241 One-dimensional joints
• CPC Class Codes: B25J 19/02 Sensing devices
• CPC Class Codes: B25J 3/04 involving servo mechanisms servo-actuated heads B25J15/02
• CPC Class Codes: B25J 9/1045 comprising tensioning means
• CPC Class Codes: B25J 9/1607 Calculation of inertia, jacobian matrixes and inverses
• CPC Class Codes: B25J 9/1689 Teleoperation
• CPC Class Codes: G05B 2219/39457 Tendon drive
• CPC Class Codes: G05B 2219/41032 Backlash
• CPC Class Codes: G05B 2219/45123 Electrogoniometer, neuronavigator, medical robot used by surgeon to operate

Abstract

The present invention is a low friction, low inertia, six-axis force feedback input device comprising an arm with double-jointed, tendon-driven revolute joints, a decoupled tendon-driven wrist, and a base with encoders and motors. The input device functions as a master robot manipulator of a microsurgical teleoperated robot system including a slave robot manipulator coupled to an amplifier chassis, which is coupled to a control chassis, which is coupled to a workstation with a graphical user interface. The amplifier chassis is coupled to the motors of the master robot manipulator and the control chassis is coupled to the encoders of the master robot manipulator. A force feedback can be applied to the input device and can be generated from the slave robot to enable a user to operate the slave robot via the input device without physically viewing the slave robot. Also, the force feedback can be generated from the workstation to represent fictitious forces to constrain the input device'"'"'s control of the slave robot to be within imaginary predetermined boundaries.

Claims

1. A robot manipulator coupled to an external device, said robot manipulator comprising:

an actuator base with plural actuators and having a mechanism for receiving forces generated by said external device;

an end effector interactive with an operator;

a force feedback sensor coupled between said end effector and said actuator base for receiving said forces from said actuator base, converting said forces into feedback forces, and providing said feedback forces to said operator;

plural arms extending seriatim between said end effector and said actuator base; and

plural joints connected between pairs of adjacent arms;

wherein each one of said plural joints comprises a coupling device for mechanically coupling respective ones of said actuators to respective ones of said joints through intermediate ones of said joints, and wherein said coupling device is decoupled from said intermediate joints.

2. The invention as set forth in claim 1, wherein said external device is an output robot manipulator.

3. The invention as set forth in claim 1, wherein said external device is a programmed processor for producing fictitious forces.

4. The invention as set forth in claim 3, wherein said coupling device comprises:

a first keying drive component coupled to a second keying drive component;

a first passing drive component coupled to respective ones of said actuators for receiving rotational motion; and

a second passing drive component coupled to said first passing drive component for receiving said rotational motion from said first passing drive component and for transmitting said received rotational motion to one of said plural joints;

wherein said first and second keying drive components are constrained to rotate about one another to define an instantaneous center of rotation;

wherein said first passing drive component rotates with respect to said second passing drive component about said instantaneous center of rotation.

5. The invention as set forth in claim 4, wherein said first keying drive component is a first keying pulley and said second keying drive component is a second keying pulley.

6. The invention as set forth in claim 5, further comprising plural keying cables for rotatably coupling said first keying pulley to said second keying pulley and for rotationally constraining said first keying pulley to said second keying pulley so that said first and second keying pulleys rotate with respect to one another about said instantaneous center of rotation.

7. The invention as set forth in claim 4, wherein said first and second keying drive components are keying spur gears.

8. The invention as set forth in claim 4, wherein said first and second passing drive components are passing spur gears.

9. The invention as set forth in claim 4, wherein said first passing drive component is a first passing pulley and said second passing drive component is a second passing pulley.

10. The invention as set forth in claim 9, further comprising plural passing cables for rotatably coupling said first passing pulley to said second passing pulley and for rotationally constraining said first passing pulley to said second passing pulley so that said first and second passing pulleys rotate with respect to one another about said instantaneous center of rotation.

11. The invention as set forth in claim 3, wherein all actuators drives of said manipulator are located within said actuator base.

12. The invention as set forth in claim 3, wherein each of said joints comprises dual independent antibacklash drive transmission preloaded with respect to one another.

13. The invention as set forth in claim 3, wherein said plural joints further comprises an antibacklash mechanism for transmitting motion without backlash from respective ones of said plural actuator drives to respective ones of said joints, said antibacklash mechanism comprising:

at least a first transmission stage comprising first dual drive components, wherein both of said first dual drive components are rotatably coupled to said respective ones of said plural actuator drives and are independently rotatable with respect to one another; and

at least a second transmission stage comprising a second dual drive reduction mechanism, wherein each one of said second dual drive reduction mechanism is rigidly attached to one of said first dual drive components and is rotatably coupled to said respective ones of said joints, so that rotational motion of said respective ones of said plural actuator drives is transmitted through said first and second stages, to said respective ones of said joints without backlash.

14. The invention as set forth in claim 1, further comprising a universal joint coupled to said end effector.

15. The invention as set forth in claim 14, wherein said universal joint includes dual bearing rings attached to pitch and yaw actuation links to provide decoupling of said pitch and yaw actuation links and zero backlash in all axes.

16. A robot manipulator coupled to an external device, said robot manipulator comprising:

an actuator base with plural actuators and having a mechanism for receiving forces generated by said external device;

an end effector interactive with an operator;

a force feedback sensor coupled between said end effector and said actuator base for receiving said forces from said actuator base, converting said forces into feedback forces, and providing said feedback forces to said operator; and

a plurality of joints each coupled to said actuators, wherein each one of said joints comprises,

an input link having at least an input keying drive component rotatable on an input axis,

an output link coupled to said input link and having at least an output keying drive component rotatable on an output axis,

wherein said input and output keying drive components are constrained to rotate about one another to define an instantaneous center of rotation,

at least an input passing drive component rotatable on said input link and coupled to said actuator for receiving rotational motion, and

at least an output passing drive component rotatable on said output link and coupled to said input passing drive component for receiving said rotational motion decoupled from said one joint.

17. The invention as set forth in claim 16, wherein said input passing drive component rotates with respect to said output passing drive component about said instantaneous center of rotation.

18. The invention as set forth in claim 16, wherein said input keying drive component is an input keying pulley and said output keying drive component is an output keying pulley.

19. The invention as set forth in claim 18, further comprising plural keying cables for rotatably coupling said input keying pulley to said output keying pulley and for rotationally constraining said input keying pulley to said output keying pulley so that said input and output keying pulleys rotate with respect to one another about said instantaneous center of rotation.

20. The invention as set forth in claim 16, wherein said input and output keying drive components are keying spur gears.

21. The invention as set forth in claim 16, wherein said input and output passing drive components are passing spur gears.

22. The invention as set forth in claim 16, wherein said input passing drive component is an input passing pulley and said output passing drive component is an output passing pulley.

23. The invention as set forth in claim 22, further comprising plural passing cables for rotatably coupling said input passing pulley to said output passing pulley and for rotationally constraining said input passing pulley to said output passing pulley so that said input and output passing pulleys rotate with respect to one another about said instantaneous center of rotation.

24. The invention as set forth in claim 16, wherein said input and output links are coupled to each other by hinged side struts.

25. The invention as set forth in claim 16, wherein said input link further comprises plural input idler pulleys and said output link further comprises corresponding plural output idler pulleys, wherein each corresponding pair of said input and output idler pulleys drives one of said joints.

26. A robot manipulator coupled to an external device, said robot manipulator comprising:

an actuator base with plural actuators and having a mechanism for receiving forces generated by said external device;

an end effector interactive with an operator;

a force feedback sensor coupled between said end effector and said actuator base for receiving said forces from said actuator base, converting said forces into feedback forces, and providing said feedback forces to said operator; and

a plurality of joints each coupled to said actuators, wherein each one of said joints comprises,

an input link having an input keying pulley,

an output link coupled to said input link and having an output keying pulley,

a keying cable for rotatably coupling said input keying pulley to said output keying pulley, wherein said input and output keying pulleys are constrained to rotate about one another thereby defining an instantaneous center of rotation,

at least one input idler pulley rotatable on said input link and coupled to said actuator for receiving rotational motion,

at least one output idler pulley rotatable on said output link, and

at least one passing cable coupled to each input and output idler pulley for transmitting rotational motion of said input idler pulley and said output idler pulley decoupled from said one joint.

27. The invention as set forth in claim 26, wherein said input idler puller rotates with respect to said output idler pulley about said instantaneous center of rotation.

28. The invention as set forth in claim 26, wherein said input and output links are coupled to each other by hinged side struts.

29. The invention as set forth in claim 26, wherein said input and output links are displaced by at least a diameter of each of said input and output links to facilitate 180 degree rotation.

30. The invention as set forth in claim 26, wherein rotation of each of said joint is dependant upon a diameter ratio between said input and output keying pulleys.

31. The invention as set forth in claim 26, wherein all of said keying pulleys have the same diameter.

32. The invention as set forth in claim 26, wherein said input link further comprises plural input keying pulleys and said output link further comprises plural output keying pulleys.