Study On Planar Inertia Piezoelectric Moving Mechanism

This paper is supported by combined funds, which includes the national nature science foundation project"The theoretical and experimental research on a new micro piezoelectric translation mechanism"and the special fund for doctoral subject of college and university"The research on micro stick-slip mechanism driven by piezoelectric elements".Along with the developing of micro / nano-science and technology, the research area of the people has continued to deepen, having expanded the object of operation from the macro area to micro area. For completing of a more subtle and sophisticated operation, the Movement system accuracy has been put a higher standard, especially in biomedical engineering, precision machining, robotics, computer, automation, precision measurement and precision devices micro-fabrication and ultra-precision processing and so on, the micro/nano-precision positioning/driving technology are also in increasing demand, researching and development of the precision actuators that based on the different principles and structure attracted more people's attention. Based on the summarization of domestic situation and abroad, at present, most inertial piezoelectric moving mechanism realize directional motion by using the appropriate mechanical structure with combination of the inverse piezoelectric effect of piezoelectric elements, which is cotrolled orderly by the suitable circuit system. The working principle of the driven mechanism which is driven by the inertial impact force using of the rapid deformation of piezoelectric elements is: piezoelectric elements can produce rapid elongation, slow shortening, or slow elongation and rapid shortening when are applied by the input signal similar to sawtooth through the design of electrical systems, so in the role of the turn signal the driven mechanism realize single direction movement in the macro level. In this paper, under the premise of research institutions in the full analysis of the piezoelectric driven mechanism both at home and abroad, making use of the surface friction and piezoelectric materials of the inertial force changing orderly to form micro-displacement principle, we developed a new inertia piezoelectric actuator. And we have developed and researched for the new driver through theoretic analysis, finite element analysis, tribology analysis and test methods.1. Key technology analysis of planar inertial piezoelectric moving mechanism The drive elements of planar inertia piezoelectric moving mechanism are the critical factors, so the piezoelectric stack is necessary to be analyzed deeply. The mathematical model of piezoelectric stack is established using energy method and the transfer function of piezoelectric stack is obtained; the simplified model of piezoelectric stack is obtained based on the equivalent circuit theory; the FE model is established by FEM, and the output displacement characteristics, open-circuit stiffness and short-circuit stiffness is analyzed. The natural frequency and modal is analyzed with the modal analysis; the dynamic model of piezoelectric stack is established, the characteristics of frequency,the output displacement and inertial force are simulated, The nonlinear hysteresis characteristics of piezoelectric stack is analyzed, focused on Preisach modeling technology and Preisach modeling process, the predicted curve of Preisach model is obtained.The contact surface friction is analyzed, three kinds of typical friction models are given, analyzed the heysteresis phenomenon of the friction and the influence of the inertia impact, combined with Leuven model and Bouc-Wen model, dynamic model of simple inertia piezoelectric drive mechanism is established, analyzed the movement characteristics and hysteresis characteristics of friction, laying a foundation for the experimental study.2. The design and experimental study of planar linear inertial piezoelectric stack moving mechanismBased on the analysis of the current domestic and foreign common inertial piezoelectric drive mechanism, by using of changing the contact surface with the positive pressure to change the friction force, combined with the horizontal direction of the inertial force of orderly changes, a kind of novel planar inertial piezoelectric stack moving mechanism was proposed, the movement principle and condition of mechanism are analyzed; the dynamic of the mechanism is established, which is based on the movement principle and force analysis of planar inertial piezoelectric stack moving mechanism, the dynamics simulation of the mechanism is carried out by using of MATLAB, and the dynamic characteristics of moving mechanism is analyzed;The planar inertial piezoelectric stack moving mechanism prototype are designed and manufactured on the basis of simulation results, the experimental test system is set up to carry out the basic experimental research, the curve of the output displacement, the relationship of velocity and driving voltage, frequency are obtained, as well as the mechanism load characteristic curve, at the same time the deviation error from the straight-line movement is analyzed; with regard to the larger deviation error from the straight-line of planar inertia piezoelectric stack moving mechanism, the moving mechanism based on V-shaped Groove is designed, the improved moving mechanism experimental prototype is manufactured and relate experiment tests are carried out, the experiment result shows that the performance of the improved moving mechanism in the low-frequency conditions is stable, the output displacement, velocity curve have better linearity, at the same time deviation error from a straight line have a very good control. 3.The design and experimental study of planar inertial piezoelectric stack rotary mechanismA new type of inertia piezoelectric stack rotary mechanism is proposed, the force and movement condition of rotary mechanism are analyzed, the dynamic model of rotary mechanism is established; a rotary mechanism prototype are designed and manufactured, the kinematics simulation and experiment study of rotary mechanism are carried out, through contrast simulation and experimental curves, which verified the dynamic model of the rotary mechanism is correct; At the same time, the performance of the rotary mechanism are tested; according to the existence of large radial run-out error of the rotary mechanism, the improved rotary mechanism is designed, the piezoelectric stack angle of the improved rotary mechanism is adjustable, the contact surface of stator and rotor is cone, through experiment test, it is shown that the existence of large radial run-out error are effectively resolved, the impact on stability and repeatability error of plane inertia piezoelectric stack rotary mechanism is analyzed, the impact of the accuracy of the processing, installation, measurement, environmental and other factors on the performance of rotary mechanism is studied.4. Study of planar 3-DOF inertial piezoelectric stack moving mechanismPlanar 3-DOF inertial piezoelectric stack moving mechanism is designed, the movement principle of the mechanism is analyzed; the dynamics model of the mechanism is established, the movement performance of the system is analyzed by simulation in detailed; Planar 3-DOF inertial piezoelectric stack moving mechanism experimental prototype is produced, the curve of the relationship between the mechanism movement performance and impact parameters are obtained through the system experimental test; Because of the existence of the interfere phenomenon in the course movement of the mechanism, the movement performance of the mechanism are affected, the output coupling control system of the mechanism is set up, and the test results show that the system can effectively reduce the interference error of the movement and positioning accuracy are very good.5. Study on planar inertial piezoelectric stack moving mechanism control systemThe impact of plane inertial moving mechanism positioning accuracy have two main factors: one is the residual oscillation, the other is the steady-state error, in this chapter the two major factors for the elimination of the residual oscillation and reduce the steady-state error of are studied.(l) analysis of the basic concepts of input shaper and the input shaper design method are analyzed; the input shaper is designed based on the zero-pole cancellation, and the elimination effects of the residual oscillation is tested through relative experiment, the experimental results showed that the residual oscillation controller based on the input shaper technology can well eliminate the residual oscillation micro-displacement working platform .(2) In order to meet the needs of open-loop control, the double feed-forward control based on input shaping techniques and piezoelectric ceramic hysteresis non-linear Preisach model is analyzed, the input shaping techniques are used to solve the residual oscillation in c feed-forward control, Preisach hybrid model is used to speed up the system positioning speed and eliminate the steady-state error. The control method eliminates the residual oscillation in the general open-loop control.(3)In order to meet the needs of high-precision closed-loop control, in the basis of analyzing double feed-forward control of input shaping techniques and piezoelectric ceramic hysteresis non-linear Preisach model, hybrid PID feedback controller based on double feed-forward compensation is designed.Experiments show that the controller can effectively eliminate the residual oscillation and reduce the steady-state error and improve the micro-displacement of the positioning accuracy.The research paper covers much knowledge in various fields such as piezoelectricity, mechanics, electricity, vibration analysis, tribology, so the research integrates multi-disciplinary knowledge. The study of this project provides a new way to study the type of actuator, will further promote the development of piezoelectric actuator technology research to a new level. The study providing valuable ideas for miniature machines, robots and other aspects of body movement, has important significance to promoting the development of new machinery.