Research on key techniques of nanometer scale macro-micro dual-drive precision positioning

Abstract

With the development of science and technology, high precision of positioning platform is needed in many areas, for example, cell fusing in biology and precision surgery in medical area. In such areas, both high efficiency and high precision are needed in some cases, for example, semiconductor processing equipment, super precision lathe etc. In a word, precision positioning platform becomes an important tool in exploring microscope world. Precision positioning platform is a key element in microscope operation. Macro/micro dual-drive precision positioning is a key technique in high-efficiency high-precision area. By such techniques, large distance and high precision can get. In order to realize nanometer scale macro/micro dual-drive precision positioning there are some key problems. First, system structure of macro/micro combination precision positioning platform is worthy to work on. Another key work is realization method of micrometer scale macroscope motion and nanometer scale microscope motion. The third is mechanics, drive, detection and control techniques in nanometer scale positioning of piezoelectric ceramics drive, in which realization of nanometer scale microscope positioning and micro drive is important by solving hysteresis, creep deformation and non-linearity in piezoelectric ceramics driving. To solve hysteresis problem, instead of traditional Preisach algorithm, a new type hysteresis model with simple computation and identification is needed. The inverse model is also easily to get. So we can present new control method to solve hysteresis and creep deformation problem based on this inverse model. Another way, hysteresis and creep deformation problem exist in traditional voltage-feedback power source for piezoelectric ceramics. To solve this problem, a new type current feedback power source for piezoelectric ceramics is presented. In the end, a macro-micro dual-drive super precision positioning mechanism is presented. Combining macro with micro actuator, a system with large workspace and high resolution of motion is presented. The linear direct-drive motor is used in the macroscope motion and high frequency PZT-driven microscope stage is embedded in the motor and compensates the position error. A high-resolution linear encoder is integrated into the closed-loop feedback, which is used to measure the position of the end-effect in microscope scale.