Flat Small Size Piezoelectric Actuator Operating in Several Modes

Abstract:
A new piezoelectric actuator is proposed and analyzed. It can operate in rotary and linear modes. The actuator consists of four beams that are composed in a cross-type structure. Four bimorph piezoelectric plates are located at the end of each beam and are used to excite in-plane or out-of-plane vibrations of the structure. Dimensions of the actuator are 32x32x0.7mm. The piezoelectric actuator can operate as a stator of rotary or linear type motor depending on the vibration mode of the actuator. Four harmonic signals with phase-shifted by π/2 are used for obtaining rotation motion, while two sawtooth or rectangular waveform signals shifted by π are used for generating linear motion. Both in-plane and out-of-plane vibration modes can be employed to obtain rotary motion, while just out-of-plane mode is used for linear movement of the slider. Different type of moving element is needed to get linear and rotary motions. The numerical and experimental investigation was performed to validate the operation principle of the motor and to measure mechanical output characteristics. Experimental results showed that maximum average rotation speed of 731.23 rpm and 1068.29 rpm were obtained at 90 Vp-p and 120 Vp-p when actuator operated at in-plane and out-of-plane bending modes, respectively. Moreover, the maximum average linear velocity of 4.75 mm/s was obtained at 200 Vp-p while the preload force was 1 mN.