Patent
1992-01-17
1994-06-28
MacDonald, Allen R.
395 95, B25J 1900
Patent
active
053254678
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a robot control method based on an acceleration/deceleration time constant, by which the operation of the robot is controlled by deciding the acceleration/deceleration time constant of a servomotor, and more particularly, to a robot control method based on an acceleration/deceleration time constant in which an optimum acceleration/deceleration time constant is determined for each block of movement of the robot to thereby control the operation of the robot.
2. Description of the Related Art
When a robot is adjusted on site, an acceleration time constant and deceleration time constant are set for each servomotor which drives each arm of the robot. The acceleration time constant and the deceleration time constant are combined, and thus are referred to as an acceleration/deceleration time constant. The acceleration/deceleration time constant depends significantly on the operating conditions of the robot, and therefore, it is difficult to establish a particular time constant to be applied to all cases. Accordingly, it must be decided by empirical judgements and trial operations, and the like.
Setting those time constants with such allowances, however, prolongs the cycle times, and setting them to smaller values tends to cause vibration and the like, which has an adverse affect on the positioning accuracy. Accordingly, the time constants must be set to exact values, but it is difficult to determine a standard on which quickly made objective judgements can be based, and accordingly, it is difficult to increase the operating speed when the robot is controlled with acceleration/deceleration time constants having large allowances, even when allowances are given to the torques of the servomotors.
SUMMARY OF THE INVENTION
The present invention is intended to solve the above-mentioned problem, and the object of the present invention is to provide a robot control method based on exact acceleration/deceleration time constants, whereby optimum acceleration/deceleration time constants of servomotors are established in accordance with an amount of movement and a load, and the like. Each servomotor is controlled to move each axis in the robot.
To attain the aforementioned object, a robot control method based on an acceleration/deceleration time constant is provided, in which the acceleration/deceleration time constant of a servomotor is determined for each block of movement of the servomotor moving one axis, to thereby control the operation of the robot, and wherein a reaching speed is determined from the amount of movement of the block, the output torque of the servomotor is determined from the reaching speed of the block controlled by the servomotor, a static load torque is subtracted from the output torque to determine an acceleration torque, an acceleration is determined from a load inertia of the acceleration torque and the servomotor, and an acceleration/deceleration time constant is determined from the obtained acceleration.
Therefore, the reaching speed is determined from the amount of movement of a block to be implemented. For example, if the amount of movement is small, then the reaching speed is also small, and if the amount of movement exceeds a certain value, then the reaching speed becomes a teaching speed. The speed of the servomotor is obtained from the reaching speed, and an output torque of the servomotor can be determined from the torque curve. A viscosity loss is subtracted beforehand to obtain the speed and torque curve. The accelerating torque for accelerating a load is obtained by subtracting the static load torque consisting of a friction torque and a torque from gravity, and the like, from the output torque, and the acceleration/deceleration time constant is determined from the accelerating torque, to thereby control the acceleration and deceleration of the robot.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a flowchart of the robot control method based on the acceleration/deceleration time constant according
REFERENCES:
patent: 4554497 (1985-11-01), Nozawa et al.
patent: 4603286 (1986-07-01), Sakano
patent: 4819184 (1989-04-01), Jonsson et al.
patent: 4908556 (1990-03-01), Daggett et al.
patent: 5166872 (1992-11-01), Weaver et al.
Kato Tetsuaki
Kinoshita Satoshi
Naito Yasuo
Nihei Ryo
Torii Nobutoshi
Fanuc Ltd.
MacDonald Allen R.
LandOfFree
Robot control method based on an acceleration/deceleration time does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Robot control method based on an acceleration/deceleration time , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Robot control method based on an acceleration/deceleration time will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2383052