| 摘要 |
PURPOSE:To remove the hysteresis characteristics of a piezoelectric element and to contrive to be able to obtain a linear displacement to a command signal by a method wherein a piezoelectric element of the same kind as the above piezoelectric element is connected in series with the above piezoelectric element to detect the amount of charge of the above piezoelectric element and the voltage of the latter piezoelectric element is feeded back. CONSTITUTION:The amount of charge of a piezoelectric element 1 is detected to obtain a feedback signal. As a detecting means for the amount of charge, a piezoelectric element 2 of the same kind as the element 1 is used in series connection, for example, with the element 1 and the detected signal is feeded back by a high input impedance amplifier. Accordingly, the amounts of charge of the element 1 for an actuator and the element 2 for detection become equal to each other and when the voltage of the element 2 is feeded back, the feedback signal to correspond to the amount of charge of the element 1 can be obtained. Moreover, when the voltage of the element 2 is feeded back through a high input impedance amplifier 4, the hysteresis of the element 1 is removed. |
