Manipulator controlling apparatus

• US 4,950,116 A
• Filed: 08/18/1989
• Issued: 08/21/1990
• Est. Priority Date: 08/18/1988
• Status: Expired due to Term

• Current Assignee: Nec Toshiba Space Systems, Ltd. (NEC Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Nishida, Shinichiro
• Primary Examiner(s): Spar, Robert J.
• Assistant Examiner(s): Hienz, William M.
• Application Number:
  US07/395,721
• Time in Patent Office: 368 Days
• Field of Search: 414/5, 414/909, 901/8, 901/9, 244/234, 244/236, 244/237
• US Class Current: 414/5
• 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: G01L 5/226 to manipulators, e.g. the force due to gripping
• CPC Class Codes: G05B 19/427 Teaching successive positions by tracking the position of a joystick or handle to control the positioning servo of the tool head, master-slave control G05B19/423 takes precedence
• CPC Class Codes: G05B 2219/33263 Conversion, transformation of coordinates, cartesian or polar
• CPC Class Codes: G05B 2219/37357 Force, pressure, weight or deflection
• CPC Class Codes: G05B 2219/37396 Tactile feedback, operator feels reaction, force reflection
• CPC Class Codes: G05B 2219/40195 Tele-operation, computer assisted manual operation

Abstract

Apparatus for controlling a manipulator employs a control device, first to third detectors, a producing device and a driving device. The first detector detects an operating force/torque generated by the control device and the second detector detects a deflecting amount of the control device from a reference position. The third detector detects an end force applied on an end portion of the manipulator and reaction signals are generated by the producing device. The reaction signal corresponds to a function of the deflecting amount and the end force. A force/torque corresponding to the difference between output signals from the first detector and the producing device are generated by the driving device and applied on the control device.

Claims

1. Apparatus for controlling a manipulator, which has an end portion, in response to an external force, comprising:

control means for generating an operating force/torque corresponding to the external force;

first detecting means for detecting the operating force/torque generated by the control means;

second detecting means for detecting a deflecting amount corresponding to the movement of the control means from a reference position;

third detecting means for detecting an end force applied on the end portion of the manipulator;

producing means connected to the second and third detecting means for generating reaction signals corresponding to a function of both the deflecting amount and the end force; and

driving means for generating driving signals corresponding to the difference value between values of output signals from the first detecting means and the producing means, and applying force/torque corresponding to the driving signals on the control means.

2. The apparatus of claim 1, wherein the control means includes three translation axes substantially orthogonal to one another and three rotation axes substantially orthogonal to one another.

3. The apparatus of claim 1, wherein the producing means includes means for preventing an oscillation of the reaction signals.

4. The apparatus of claim 2, wherein the second detecting means includes means for detecting the deflecting amount of the control means from a neutral position.

5. The apparatus of claim 1, wherein the producing means includes means for converting coordinates of data corresponding to the end force.

6. The apparatus of claim 1, wherein the producing means includes means for generating different reaction signals corresponding to a sign of the deflecting amount.

7. The apparatus of claim 6, wherein the producing means includes means for calculating reaction force F_R from the deflecting amount X and the end force f in accordance with the following relationship:

space="preserve" listing-type="equation">F.sub.R =0(-a<

x<

a),

space="preserve" listing-type="equation">F.sub.R =KaX-a/Ka(x≧

a);

space="preserve" listing-type="equation">F.sub.R =KbX+a/Kb(x≦

-a);

where Ka and Kb are expressed by functions of the end force f and a is constant.

8. The apparatus of claim 7, wherein Ka and Kb are related as follows,

if f≧

0, Ka=C|f|+Co and Kb=Co; and

if f<

0, Ka=Co and Kb=C|f|+Co;

where C and Co are constants.

9. The apparatus of claim 1, wherein the producing means includes means for generating different reaction signals corresponding to a sign of the end force.

10. The apparatus of claim 1, wherein the producing means includes means for generating the reaction signals corresponding to reaction force/torque which have approximately symmetrical characteristics to a reference position on a predetermined axis.

11. The apparatus of claim 1, wherein the producing means includes means for calculating the reaction signals corresponding to six degrees of freedom.

12. The apparatus of claim 1, wherein the driving means includes multiplying means for multiplying the difference value and a value corresponding to a coefficient of viscosity when the control means is considered to be supported by an elastic mechanism;

a motor driver for driving the manipulator by speed control;

sensing means for detecting rotational velocity of the motor driver;

subtracting means for detecting difference signals between outputs from the multiplying means and the sensing means; and

compensating means responsive to output from the subtracting means for generating desired torque, and producing the torque to the motor driver.

13. The apparatus of claim 1, wherein the producing means includes means for generating signals corresponding to an absolute value of reaction force which increase rapidly when an absolute value of the deflecting amount exceeds a predetermined value.

14. The apparatus of claim 1, wherein the driving means includes means for generating desired torque by a PID controller;

and

a motor driver responsive to the desired torque for driving the control means.