Design, analysis and experimental research of a novel single-phase driven rod-type rotary piezoelectric actuator.

Piezoelectric actuators operated by single-phase excitation are widely studied for precision drive applications, attributed to their reduced control complexity, adaptable design, and small form factor. Nevertheless, these actuators are primarily designed for linear motion, which is plagued by structural complexity, severe wear, and frequency drift. Monophase-driven rotational piezoelectric actuators face challenges in the construction of operating mode, actuation stability, and bidirectional rotation. To address these limitations, a novel single-phase driven rod-type rotary piezoelectric actuator is proposed, which adopts a dual rotor symmetrical structure. The stator is constructed as a rod-type piezoelectric composite beam formed by two piezoelectric ceramic (PZT) groups embedded in a metal matrix. The single-phase signal excites the coupled longitudinal-torsional vibration mode of the stator, realizing the continuous circumferential rotational motion of the rotors, and bidirectional continuous rotation is achieved by exciting different PZT groups. Firstly, the motion trajectory equation of the driving foot is established, and the stator's geometry and operating modes are determined using finite element analysis (FEA). Secondly, the vibration characteristic experiment obtains the amplitude frequency characteristics and vibration mode of the stator of the principle prototype, compares the finite element calculation results, and verifies the accuracy of the finite element analysis. The amplitude-frequency characteristics and vibration mode of the stator are acquired via vibration characteristic experiments, compares the finite element calculation results, and verifies the accuracy of the FEA. Finally, assemble the actuator prototype and conduct experimental research. The results show that under the excitation voltage of 300 V, the maximum no-load speed, torque, and minimum rotational resolution of the actuator are measured as 200 rpm, 1.7 mN m, and 0.6 mrad, respectively. Both finite element analysis and experimental research have verified the correctness of the operating principle and the feasibility of the structural scheme of the proposed actuator, providing a new driving scheme for applications in narrow space environments.