| 摘要 |
PURPOSE:To adjust the quantity of displacement accurately by installing a common constant current source between a charging circuit and a discharging circuit for a piezoelectric actuator, and controlling the duration of the flow of current to control the quantity of displacement of the piezoelectric actuator. CONSTITUTION:A common constant current source 5 is mounted between a charging circuit and a discharging circuit including a piezoelectric actuator 2. A length measuring machine 18 and a length measuring counter 17 for measuring the quantity of displacement of a displacement member 20 for positioning controlled by the piezoelectric actuator 2 are set up. The length measuring values of these length measuring means and an aimed length measuring value are compared, and the charging circuit or the discharging circuit is selected by a control circuit 16 by a deviation among them and switch corresponding to the circuit is turned ON. The operating time of the constant current source 5 is controlled by a timer 19 in response to the deviation. Accordingly, hysteresis is eliminated in the quantity of displacement, thus improving accuracy. |
