Development Of Micro-positioning Platform Driven By PZT For Precision Machining

Stepping into the 21st century, with the requirement of aeronautics, integrated electronic manufacture, MEMS, manufacture technology for high precision and high quality is required. Precision machining technology is a research field mainly sponsored by the country, and micro-positioning system with high performance is the key to realize precision machining. Closely related with the practical problems in engineering, this dissertation deals with positioning worktable for precision grinding machine tool in order to improve machining accuracy. It is highly worth of researching and has real engineering value.As its inverse piezoelectricity effect, PZT ceramic may get micro position under DC power and is linear to the voltage of the driven power. PZT ceramic has superior characteristics in micro position system than other actuators, such as small volume, high motion resolution & repetition accuracy, rapid motion speed, big output force and relative simple control method, and it's a widely used actuator in micro position system. A useful micro precision table in engineering was developed based on the motion characteristics of PZT actuator, parallel flexure hinge design theory, control system theory and micro-positioning sensor. Design and application of the PZT driven micro-positioning table were studied. The main work and achievements are illustrated as follows.(1) The blue print design of the micro position system is considered as a whole.(2) Based on the right angle flexure hinge, a monolith flexure table is designed and tested. The model of the flexure hinge and the table were setup, and the vibration, static and the dynamic characteristics of the platform were deduced with the finite elements analysis.(3) The displacement characteristics of the PZT actuator is analyzed andtested. The non-linear model of the PZT actuator was also made andthe data was given. (4) Based on the analysis of the micro position close loop control system,tradition close-loop system was developed which was tested to beeffective to conquer the hysteresis, creep and the disturbance of theenvironment.The developed micro-positioning platform was used on a CNC lathe. ±0.1μm positioning precision and surface roughness of 0.4/μm were achieved in machining axis. The feasibility of the theory formula and the FEA analysis method was proved with the coincidence of the theory, FEA and the experiment results.