| 摘要 |
PROBLEM TO BE SOLVED: To prevent a piezoelectric actuator from being vibrated in a primary natural vibration frequency, by means of a simple drive circuit.SOLUTION: In accordance with a driving method for changing a voltage to be applied to a piezoelectric element from an initial voltage to a final target voltage within a period equal to or less than 1/f for the piezoelectric actuator having a primary natural vibration frequency (f), a drive period for changing the voltage to be applied to the piezoelectric element from the initial voltage to the final target voltage includes a voltage application period. During the voltage application period, a voltage V changes in proportion to a time (t). During the voltage application period, a fixed current is made flow into the piezoelectric element as a capacitive load, and the application voltage to the piezoelectric element is raised in proportion to a current inflow time. Otherwise, a fixed current is made flow out of the piezoelectric element and the application voltage to the piezoelectric element is dropped in proportion to a current outflow time. When the fixed current is defined as I, electrostatic capacity of the piezoelectric element is defined as C and the inflow or outflow time of the fixed current is defined as (t), a voltage represented by V=tI/C is applied to the piezoelectric element in such a manner that displacement is stopped without vibration together with the end of the voltage change to the final target voltage. |
