Design and Simulation of a Sliding Mode Controller for Reducing Radial Vibration of an Eccentric Rotor Equipped with an Automatic Dynamic Balancer

An automatic dynamic balancer is installed on a rotor system in order to reduce radial vibrations caused by eccentricities. However, it is found that due to rolling friction between the balancing balls and race, the ball may not be able to be precisely settled at the desired equilibrium position for each rotor speed-up. This inconsistence of ball mis-positioning results in even larger residual vibrations. This study is dedicated to design a feedback control scheme to overcome this problem. The method of sliding mode control is proposed herein to accomplish this objective by activating the control scheme from the onset of system dynamics until the ball precisely settles at the desired angular position. In this way the system becomes passive after the ball finds its desired angular position, i.e., saving energy for the control effort. The system augmented with the control scheme is simulated to verify the validness of the control.