Three Degree of Freedom Piezoelectric Actuator for Precise Positioning

A novel three degrees of freedom actuator is introduced and investigated in this paper. Actuator comprises a single cylinder type piezoelectric transducer with a disc shaped resonator glued on the top of the cylinder and a reflecting mirror. Ring shaped permanent magnet is used to clamp mirror on a steel hemisphere that is located in the center of the disc resonator. Actuator can realize up to three degrees of freedom i.e. to rotate the mirror about three axes independently. Harmonic vibrations of the resonator are excited by piezoelectric transducer and are employed to rotate the mirror. Bi-directional rotation of the mirror is obtained by switching excitation signals between different electrodes of the transducer. Both numerical simulation and physical prototype are used to verify the operating principle and results. Numerical investigation of the piezoelectric actuator was performed to investigate modal-frequency and harmonic response analysis of the piezoelectric actuator. Experimental study was used to measure electrical and mechanical output characteristics of the piezoelectric actuator. Results are analyzed and discussed.