Structural Design and Dynamic Characteristic Analysis of Short-column Micro Piezoelectric Power Actuator

Abstract

Background:: With the rapid development of science and technology, industrial products continue to develop towards the direction of lightweight and miniaturization, and the demand for power sources to drive micromachinery is increasing, so the patents related to microactuators are also increasingly valued. The microactuator based on a piezoelectric drive converts the deformation energy of the piezoelectric body into the kinetic energy of the transmission mechanism to drive the output shaft rotation. The stator and the rotor of the existing actuator are the surface contact with a certain preload force. After working for a long time, the contact surface will be lost due to friction, which will reduce the response speed and rotation accuracy and even cause the rotor to slip, affecting the actuator operating life. Objective:: In order to solve the above technical problems, the author innovates the driving mode between stator and rotor and proposes a novel short-column micro piezoelectric actuator based on multi-tooth alternating meshing transmission. Methods:: Firstly, the structure and operating principle of short-column micro piezoelectric power actuator, which can realize linear motion into rotary motion, and has three main advantages: compactness in size, multi-tooth meshing drive and large driving torque, are proposed and elucidated. Secondly, the structure size of each component of the actuator is determined to complete the 3D structure design. Thirdly, the modal analysis and the harmonic response analysis of the actuator are studied. The frequency range of the sawtooth wave voltage excitation signal applied to the actuator is determined. Finally, the prototype is made, and the performance test is carried out. Results:: In this paper, a micro piezoelectric power actuator different from the existing patent is proposed, which is assembled by a drive module, a transmission module, an elastic element, an output shaft, a base module and a shell. The results show that when the excitation frequency applied by the actuator is 157Hz, the amplitude of the tooth column along the axis of the actuator is 3.071mm, the axial amplitude of the output shaft is zero, and there is no axial motion. At this time, the displacement of the tooth column is the largest, and the driving performance is the best. From the experimental results, it can be seen that the prototype appears to have intermittent rotation under this frequency excitation. Conclusion:: The proposed micro piezoelectric power actuator adopts multi-tooth alternating meshing between the stator and the rotor to transfer power, which changes the transmission mode relying on friction in the existing technology, reduces the friction loss, avoids rotor slip, and improves the response speed, rotation accuracy and operating life of the actuator. The research work in this paper provides a new idea and a new method for the research and design of micromechanical power sources.