Research Of A Planar Two-Dimensional Nano-positioner Driven By Shear Piezoelectric Actuators

With the rapid development of the nano technology, nano electromechanics system(NEMS) has been widely used in optics, electronics, precision measurement, manufacturing and other fields. Nano positioning technology is a leading edge discipline and a significant branch of NEMS. The purpose of this technology is to make the working stage to realize a minute movement on a high resolution, meanwhile, it is one of the essential tools for the researches to explore the microscopic worlds. The positioner with the nano scale resolution and high response frequency, has been widely applied in scanning electron microscopes, atomic force microscopes and precision optical platforms. In order to ensure the accuracy and reliability of the system, a two-dimentional nano-positioner in this paper has been designed.Shear piezoelectric actuator(SPA) has a good performance, i.e. compact-sized, fast response. Moreover, it can drive the working stage directly. Therefore, as the actuators of the nano-positioner, instead of the traditional extension piezoelectric actuators, SPAs have a less load and make the positioner more compact. In this way, the nano-positioner system owns higher resolution, faster response and better reliability. As the actuators, two SPAs have been superimposed, and the direction of motion of them are perpendicular. When driven by the different driving signals separately, the surface of the SPA module will realize a two-dimension motion in the horizontal plane. On the base of the stick-slip theory model, the working stage can be driven to make precise location in a nanoscale resolution. Then the kinematics model and kinetics model of the working stage have been built to analyze the problems of rotation, dumping and translational motion.For a certain structure of nano-positioner, the different driving signals have drastic effects on the system performance. In the controlling process, the problems of the saw-tooth driving signals have been analyzed. Then according to the specific requirements of the velocity and resolution, the driving effects of different driving signals have been compared by the method of MATLAB simulation analysis, and the advantages of different driving signals have also been discovered more intuitively.Finally, according to the design results, the prototype, driving system and control system have been installed. The working stage can realize a high-precision position with a nanoscale resolution in a horizontal plane, and the motion of the working stage has been measured by a capacitive sensor. Based on experiment projects, the nanopositioner performance has been measured. The experiment results have validated that the prototype in this paper can meet the design specifications and requirements.