Design And Performance Of Non-resonant Fiction Driven Piezoelectric Stack Linea Motor

Linear piezoelectric motors are widely used in the field of optical instruments,medical devices,nanotechnology and high-precision manufacturing technology due to its advantage of high precision,fast response and anti-interference ability.In recent years,the non-resonant linear piezoelectric motor has been developing rapidly in the advantages of low machining precision and high precision and good stability.However,there are still problems with the stability of large strokes and high-precision positioning.In order to solve the problem of high precision and stability in a large stroke of a linear piezoelectric motor,the linear piezoelectric motor based on friction differential drive principle.High precision friction drive technology had been achieved utilizing piezoelectric stacks with their outstanding features of large output force,large amplitude and good stability.The main contributions of this dissertation are as follows:Firstly,the research status and development trend of resonant linear motors and non-resonant linear motors are compared and analyzed.The electrical characteristics and mechanical output characteristics of piezoelectric stacks are analyzed,providing the basis for the flexible design method of piezoelectric stack actuation system.Secondly,the dynamic characteristics of piezoelectric stack system are researched.In order to improve the mechanical output characteristics of piezoelectric stacks,three flexible piezoelectric stack actuation systems is designed based on the method of the actuation system.It shows that the bilateral parallel cantilever flexible mechanism is beneficial for the protection of piezoelectric stacks and for output performance of piezoelectric stacks.Thirdly,the friction drive type non-resonant piezoelectric stack liner motor is proposed by the analysis of friction differential drive principle,then the asymmetrical voltage signal is designed.The operational principle of friction differential drive motor is researched on,and the drive foot with displacement decoupling characteristics is proposed.Further,the structure of a single foot linear piezoelectric motor is designed.Experimental results show that the motor can run steadily when the frequency varies from 1Hz to 400 Hz and realize the characteristic of wide frequency domain from the frequency response characteristic of the motor.The stroke of the motor is 200 mm,and the minimum resolution is 11 nm,which achieves the goal of high accuracy and good stability in large stroke.Finally,the biped liner piezoelectric motor is proposed because of the good mechanical output characteristics of single foot linear piezoelectric motor.Experimental results showed that the biped linear piezoelectric motor run stably when the frequency varies from 10 Hz to 1200 Hz,and the maximum thrust is 5.3N.The velocity of the motor ranges from 1.03μm/s to 609.6μm/s.All in all,the friction differential drive piezoelectric stack linear motors proposed in the paper have good mechanical output characteristics and operation stability and are almost not affected by environmental factors,which can achieve the goal of wide frequency domain,large stroke and high accuracy.