Rotary actuator and method of controlling an actuator

摘要

A piezoelectric drive body is secured to a shaft that is rotatably supported by a holder. A leaf spring is fastened to the upper end of the holder and is in resilient contact with the upper end of the shaft. Friction between the shaft and the leaf spring acts as a rotation-suppressing force on the shaft. When a sawtooth-waveform voltage is applied to the drive body, the drive body vibrates to the right and left. The drive body rotates around the shaft in a specific direction, due to the difference in inertial force resulting from the difference in the deforming speed of the body. The voltage linearly rises and falls repeatedly or has a sinusoidal waveform. In either case, the voltage rises from a minimum to a maximum for time T₁ and falls from the maximum to the minimum for time T₂ that is different from time T₁.