Robot control apparatus

• US 4,801,856 A
• Filed: 04/21/1987
• Issued: 01/31/1989
• Est. Priority Date: 04/22/1986
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Wajima, Hiroki
• Primary Examiner(s): Shoop, Jr., William M.
• Assistant Examiner(s): MARTIN, DAVID S
• Application Number:
  US07/040,873
• Time in Patent Office: 651 Days
• Field of Search: 361/23, 361/28, 361/29, 318/302, 318/563, 318/565, 318/568, 318/606, 318/362-369, 318/370-371, 318/373-382, 318/626, 901/49
• US Class Current: 318/568.22
• CPC Class Codes: G05B 19/416 characterised by control of velocity, acceleration or deceleration G05B19/19 takes precedence

Abstract

A position of an actuation unit of a robot and a speed of a motor for driving the actuation unit are detected. A speed reference is produced on the basis of a deviation between a movement value and a position detected. Further, a torque reference is produced on the basis of a deviation between the speed reference and a speed detected. The motor for driving the actuation unit is subjected to current control. The magnitude of the torque reference is limited by a limiter. This limiter operates only when a command for allowing the robot to be subjected to emergency stop is received, and carries out limiting operation on the basis of a function which rises from the time point when the command is received.

Claims

1. A robot control apparatus comprising:

a position detector for detecting a position of an actuation unit of the robot;

a position control unit for producing a speed reference on the basis of a deviation between a detection value of said position detector and a predetermined movement value;

a speed detector for detecting a speed of a motor for driving said actuation unit;

a speed control unit for producing a torque reference on the basis of a deviation between a detection value of said speed detector and said speed reference;

a current control unit for controlling a current delivered to said motor on the basis of said torque reference;

a function generator for generating a function which moderately increases its function value from a point in time when a command for allowing said robot to be subjected to an emergency stop is received;

a limiter for limiting the magnitude of said torque reference on the basis of said function; and

a switch for allowing said limiter to be operative only when said command is received.

2. A robot control apparatus as set forth in claim 1, wherein said function generator generates a function which exponentially increases.

3. A robot control apparatus as set forth in claim 2, wherein said function is generated on the basis of a time constant determined by a resistor and a capacitor.

4. A robot control apparatus as set forth in claim 1, wherein said function generator generates a function which linearly increases.

5. A robot control apparatus as set forth in claim 2, wherein said function does not increase its function value beyond a predetermined value by making use of a breakdown voltage of a Zener diode.

6. A robot control apparatus as set forth in claim 4, wherein said function does not increase its function value beyond a predetermined value by making use of a breakdown voltage of a Zener diode.

7. A robot control apparatus comprising:

a position detector for detecting a position of an actuation unit of the robot;

a position control unit for producing a speed reference on the basis of a deviation between a detection value of said position detector and a predetermined movement value;

a speed detector for detecting a speed of a motor for driving said actuation unit;

a speed control loop for producing a torque reference on the basis of a deviation between a detection unit of said speed detector and said speed reference;

a current control loop for controlling a current delivered to said motor on the basis of said torque reference;

a function generator for generating, when a command indicative of an emergency stop is produced, a function output of said torque reference which moderately increases its function value up to a predetermined function value;

a limiter for limiting the magnitude of said torque reference on the basis of said function; and

a switch for allowing said limiter to be operative only when said command is received.

8. The robot control apparatus as set forth in claim 7 wherein said function avoids an increase of its function value beyond the predetermined function value by making use of a breakdown voltage of a Zener diode.