Robot control method based on an acceleration/deceleration time constant

• US 5,325,467 A
• Filed: 01/17/1992
• Issued: 06/28/1994
• Est. Priority Date: 05/25/1990
• Status: Expired due to Term

• Current Assignee: Fanuc Ltd (Fanuc Corporation)
• Original Assignee: Fanuc Ltd (Fanuc Corporation)
• Inventors: Kinoshita, Satoshi, Kato, Tetsuaki, Nihei, Ryo, Naito, Yasuo, Torii, Nobutoshi
• Primary Examiner(s): MacDonald, Allen R.
• Application Number:
  US07/820,881
• Time in Patent Office: 893 Days
• Field of Search: 395/95, 395/96
• US Class Current: 700/261
• CPC Class Codes: B25J 9/1651 acceleration, rate control
• CPC Class Codes: G05B 19/416 characterised by control of velocity, acceleration or deceleration G05B19/19 takes precedence
• CPC Class Codes: G05B 2219/37391 Null, initial load, no load torque detection or other parameter at no load
• CPC Class Codes: G05B 2219/43009 Acceleration deceleration for each block of data, segment
• CPC Class Codes: G05B 2219/43023 Switch from acceleration to deceleration if mid stroke speed not reached
• CPC Class Codes: G05B 2219/43046 Determine time constant from command speed and needed max acceleration torque
• CPC Class Codes: G05B 2219/43059 Accelerate, decelerate all axis as function of max, min, average speed axis
• CPC Class Codes: G05B 2219/43099 Select acceleration deceleration time constants as function of weight, load, position

Abstract

A robot control method based on an acceleration/deceleration time constant wherein the acceleration/deceleration time constant of a servomotor is set for an optimum value for each block, to thereby control the operation of the robot. A reaching speed (Vu) is determined from an amount of movement (X) of a block, and based on the reaching speed, a maximum torque (Tmax) of the servomotor is determined and then a static load torque (T_wn) is subtracted from the maximum torque (Tmax) to determine an acceleration torque (Ta_n). Thereafter, based on the acceleration torque (Ta_n) and the load inertia of the servomotor, an acceleration (a_n) is determined and an acceleration/deceleration time constant (τ) is determined from the acceleration (a_n), and accordingly, an optimum acceleration/deceleration time constant is determined.

Claims

1. A robot control method based on an acceleration/deceleration time constant wherein the acceleration/deceleration time constants of servomotors, each respectively moving an axis of a robot, are set to optimum values for each block of movement of each of said axes over time, to thereby control the operation of the robot, comprising the steps of:

determining a reaching speed from an amount of movement of a block corresponding to an amount of movement of an axis of said robot moved by a servomotor over time;

determining an output torque of said servomotor moving said axis from said reaching speed;

determining an acceleration torque by subtracting a static load torque from said output torque;

determining an acceleration from said acceleration torque and a load inertia of said servomotor;

determining an acceleration/deceleration time constant from said acceleration; and

controlling said servomotor based on said determined acceleration/deceleration time constant.

2. The robot control method based on an acceleration/deceleration time constant according to claim 1, further including the step of using said static load torque as an erasable parameter at a time of teaching so that said acceleration/deceleration time constant can be changed in accordance with a load of the robot.

3. The robot control method based on an acceleration/deceleration time constant according to claim 1, further including the step of adjusting said acceleration or said acceleration/deceleration time constant with a specific constant at each teaching point of an operating program.

4. The robot control method based on an acceleration/deceleration time constant according to claim 1, further comprising the steps of determining said acceleration/deceleration time constant for each said servomotor corresponding to a respective movement block and selecting a largest value among said acceleration/deceleration time constants to control all of said servomotors.

5. The robot control method based on an acceleration/deceleration time constant according to claim 1, further comprising the step of separately determining said acceleration/deceleration time constant for each said servomotor.