Research On Three Degrees Of Freedom Rotating Inertial Piezoelectric Actuator

With the continuous progress of science and technology,many high-tech fields such as precision optics,robotics and precision machining have made great progress.As a micro actuator,piezoelectric actuator has the advantages of simple structure,no electromagnetic interference,high displacement accuracy,fast response speed,etc.,which has become a research hotspot of relevant scholars at home and abroad.However,most inertial piezoelectric actuators can only generate single or two-degree-of-freedom motion,which is difficult to meet the practical requirements of realizing multiple motion forms in a small space.Therefore,in this paper,a sandwich-type rotating inertial piezoelectric actuator with three degrees of freedom is proposed.The structure of piezoelectric actuator is designed according to the principle of inertia stick-slip drive,and the driving process of inertia stick-slip drive is analyzed.The layout of piezoelectric plate is determined.The static analysis of the piezoelectric beam is carried out and the longitudinal displacement and deflection displacement at the driving foot of the beam are obtained.The influence of the structural parameters of the beam and the parameters of the piezoelectric plate on the displacement of the driving foot of the piezoelectric vibrator beam is analyzed.The free vibration equation of piezoelectric vibrator is established and the natural frequency and mode functions of piezoelectric vibrator are solved.The influence of material parameters and structural parameters on the natural frequency of piezoelectric vibrator is analyzed.The finite element mode analysis of piezoelectric vibrator is carried out to verify the correctness of theoretical calculation.The forced vibration of piezoelectric oscillator is analyzed and the forced vibration equation of piezoelectric oscillator is established by Duhame integral.The displacement,velocity and acceleration responses of piezoelectric vibrator driving foot are obtained.The effects of different parameters on the forced response of piezoelectric vibrators were analyzed.The finite element transient analysis of piezoelectric vibrator is carried out to verify the correctness of the theoretical calculation.The machining technology of piezoelectric vibrator is studied.The prototype is fabricated and assembled.The vibration characteristics of piezoelectric vibrator are tested and the vibration displacement at the driving foot is measured.The measurement results show that the peak value of longitudinal displacement and deflection displacement at the driving foot reach 2.5μm and 1.3μm when the peak value of inlet voltage is 150 V and frequency is 320 Hz.An experimental platform for the output characteristics of the prototype was built,and the output characteristics of the piezoelectric oscillator were tested.The test results show that when the excitation voltage reaches 150 V and the signal frequency is 320 Hz,the maximum rotational speed of the spherical rotor around the x and y axes reaches 75μrad/s,and the maximum rotational speed around the z axis reaches35μrad/s.When the prototype rotates around the x and y axes,the maximum load of the prototype is 2mN.m,and when it rotates around the z axis,the maximum load of the prototype is 1.55 mN.m.