Acceleration and Deceleration of AC and DC Servomotors in Robots

Since the axis control circuit in the robot controller has the ability to control the velocity and position of each axis the motors move, a velocity profile is used with each move signal that's sent to each robot motor to provide acceleration and deceleration during the move. This profile is shown in ill. 1. Notice that the acceleration ramp occurs for the first 10-15% of the move and the deceleration occurs for the last 10-15% of the move. After the axis has accelerated, it will operate at the program speed for the distance between the two points. The acceleration and deceleration allow smooth movement for the robot as it moves all axes between the points in its program.

The robot controller has the power to operate one axis at a time or all axes simultaneously. When all axes are operated simultaneously, the microprocessor controller in the robot calculates the speed of each individual axis so that the end effector is traveling at the programmed speed.

Above: ill.1: Diagram of an acceleration and deceleration profile.