Study On Resonant-type Piezoelectric Inertial Drive Linear Motor Based On Flexible Amplification Mechanism

Resonant impact piezoelectric motors use their own natural vibration modes to synthesize asymmetric periodic vibrations,which makes up for the defects of traditional impact piezoelectric motors and greatly improve the power driving ability.However,it is very difficult to match several natural vibration modes of resonant motor with specific frequency and amplitude ratios.In this paper,a high-performance resonant-type piezoelectric inertial linear motor with matched vibration mode is designed,analyzed and tested.Two flexible amplification mechanisms excited by piezoelectric stacks are used to connect three inertial mass blocks to form an asymmetric structure.Through matching the anti-phase and in-phase longitudinal natural vibration modes of,approximate saw-tooth wave vibration is synthesized,so as to realize the high-power output capability under the resonant impact drive.The main contents and innovations of this paper are as follows:（1）Based on the theory of waveform synthesis and the principle of resonant impact drive,the asymmetric basic structure of inertial mover is proposed.Kinematic model of the inertial mover is established to analysis the natural vibration characteristics and frequency matching method.（2）Based on the inertial drive mechanism and flexible amplification mechanism,mechanical structure of the linear motor is designed.Finite element simulation model of the inertial mover is established to match their two natural vibration modes.（3）Based on the spring-mass system and friction model,system dynamics equations of the linear motor are established.Simulink numerical simulation model is established to analyze vibration characteristics of the inertial mover and motion characteristics of the linear motor.（4）A prototype is manufactured and its experimental platform is built.Frequency matching process and natural vibration characteristics of the inertial mover are tested.Output characteristics of the prototype under resonant and stepping driving states are tested,analyzed and compared.The experimental results indicate that the prototype possesses a no-load velocity of 14.6 mm/s,a stalling force of 350 mN,and a maximum output power of 1.02 mW with sinusoidal driving voltages of 40 V_p-p at 400 Hz and 19V_p-p at 800 Hz,while it also provides a stepping displacement with 0.61μm resolution with saw-tooth wave driving voltages of 10 V_p-p at 10 Hz.The experimental results confirm the effectiveness of theoretical model and dynamic analysis.This paper enriches the structure form and analysis method of resonant impact piezoelectric motor,and provides theoretical and technical support for the structure optimization and performance improvement of such kind of piezoelectric motor.