A comparison of vibration control strategies for a flexible-link robot arm

Flexible links in a robot arm often experience unwanted vibrations at the end points typically due to elastic deflections and system disturbances. This leads to reduced endpoint positioning accuracy, as well as negatively affects the overall control performance of the robot arm. Typical control strategies introduce active damping to reduce oscillations at the robot arm end points, whereas other methods apply interaction strategies based on closed-loop inverse kinematics. Other controllers, such as proportional-integral-derivative (PID) methods and the robust sliding mode controller (SMC), have also been applied to robot arms in an effort to minimize endpoint vibration. This paper studies two popular vibration control strategies found in literature, namely PID and SMC. Simulation results are generated based on applications to a flexible-link robot arm, and the results are compared and discussed.