2013 Volume 7 Issue 4 Pages 595-606
Motion analysis of balancing balls of an auto-balancer is performed in order to reduce the residual positioning error when the device passes the critical speed. The rotation speed profile control method improves the performance of an auto-balancer by providing a variable-speed period in the middle of motor acceleration at a rotation speed that passes through the critical speed. In order to confirm its effect, equations of motion of the auto-balancer mechanism including balancing balls are modeled based on a non-stationary vibration model. Time-variant dynamics of an auto-balancer in accelerating the motor are simulated by using MATLAB and the balls are confirmed to move toward the balancing position. Optimal conditions of the variable-speed period of the rotation speed profile are explored and comprehensively simulated as a parameter of start time, transit time and profile shape. It is shown that residual balancing is eliminated by the driving force of the balls. Furthermore, an experimental study is performed on an optical disc drive with an auto-balancer and vibration amplitude caused by an unbalanced disc is measured to be suppressed by the method.
