| 摘要 |
PURPOSE:To always keep a stable control action with a controller by setting a notch filter having the frequency characteristics corresponding to a band having the natural resonance frequency of a controlled system into a control system circuit and suppressing the oscillation of a specified band which is caused by the controlled system. CONSTITUTION:A notch filter 9 has the adverse gain (attenuation) frequency characteristics equal or approximate to the natural high-degree resonance frequency of an actuator 7, i.e., a controlled system of a control circuit. This notch filter 9 is set between a compensating circuit 5 and a driving circuit 6, for example, contained in a servo loop. Thus the open loop gain is reduced by the attenuating function of the filter 9. In such a constitution, a controller having the stable working is obtained with no oscillation of a servo loop even with a controlled system like an optical pickup actuator. |
