An intelligent control scheme for enhancing performance of the automatic ball-type balancer installed on high speed optical disc drives

This study is dedicated to synthesize an intelligent control scheme for overcoming the performance inconsistence caused by inevitable rolling friction of balancing balls of the automatic ball-type balancer system (ABB). The ABB is a device installed on some high-speed disk drives for reducing radial vibrations of motor spindle motion. The existence of rolling friction between the balancing ball and its runway may, however, results in the ball settling at undesirable angular positions, which greatly limit the performance for radial vibration reduction. The objective of study is to design an intelligent feedback scheme to overcome the aforementioned drawback of the ball-balancer system. The method of fuzzy logic control is proposed by activating the control scheme from the onset of system dynamics until the ball settles at the desired angular position. In this way the system becomes passive after the ball settles at its desired angular position, i.e., saving energy for the control effort. A mathematical model is first established. The influence of rolling resistance on the steady-state solution and stability of the ball is analyzed. The proposed fuzzy control scheme is then designed. The system augmented with the control scheme is simulated to verify the validness of the fuzzy logic control.