| 摘要 |
PURPOSE:To make it possible to hold displacement of an actuator in a stable state, by controlling a voltage applied to a laminated piezoelectric body in consideration also of variation in electrostatic capacity of the piezoelectric body according to temperatures. CONSTITUTION:A measuring section 3 measures total charge in a laminated piezoelectric body 2 and inputs the measured value into ar arithmetic and control section 4. The arithmetic and control section 4 calculates electrostatic capacity in the laminated piezoelectric body 2, based on the measured value from the measuring section 3 and data stored in a memory 6. According to a result of this calculation, the arithmetic and control section 4 calculates a voltage to be applied to the laminated piezoelectric body 2 according to temperatures of the piezoelectric body 2 and of atmosphere during the measurement process, and controls a voltage to be applied according to the result of the calculation. Since a voltage to be applied to the laminated piezoelectric body 2 is adjusted according to atmospheric temperatures, displacement of an actuator can be held stably at a predetermined value. |
