Vibration Control of SCARA-Type Robot Based on .MU.-Synthesis.

Abstract

Many industrial robot manipulators have a cantilever structure at the base end of which the driving motors are located. Flexibility also exists at the transmission part between the motor and the corresponding arm. In terms of control, such structure has less rigidity so that residual vibration arises at the end point of the manipulator when it is brought to a sudden stop during operation. Our aim is to design a robust controller via μ-synthesis, which eliminates the vibration, or suppresses it to an acceptable level, at the end point of the third arm of a SCARA-type robot using available information of the motor angles of the first and the second arms. The effectiveness of the derived controller is examined through simulations and experiments in comparison with a PD controller. The experimental results show that the controller can significantly suppress the residual vibration with an excellent robust performance against the uncertainty of the robot parameters, while the PD controller gives poor performance in such a case.