A Linear Piezoelectric Actuator Based on Working Principle of Three-Petal Mouth of a Rabbit

A ring-shaped linear piezoelectric actuator with three driving teeth is proposed and designed based on an axial-radial bending coupling vibration mode. The coupling vibration mode is neither pure axial bending mode nor pure radial bending mode, but an axial-radial bending hybrid one, which is generated by only one group of PZT elements and one exciting signal under an asymmetrical fixed boundary condition. The working principle of the proposed actuator is similar to the opening and closing actions of the three-petal mouth of a rabbit, which is analyzed by the finite element method. Then, the coupling vibration mode is verified by a scanning laser Doppler vibrometer after the fabrication of a prototype. Experimental results show that the prototype can achieve a maximum velocity of 60.46 mm/s and a displacement resolution of 0.5 
μ
m, and the velocity of the linear actuator can be smoothly adjusted in a wide range of 0.005–60.46 mm/s. In addition, the actuator can drive a hollow cylinder mover along different slopes without other auxiliary structures. The simulated and experimental results confirm that the proposed ring-shaped actuator is feasible without any guiding structure, which has great potential to realize further miniaturization of linear piezoelectric actuators.