In many scientific period, atomic force microscope gives so many benefits to scientists and engineers with its ultra-high microscopic ability. Atomic force microscope can evaluate surface of some sample with resolution of atomic size. And this high resolution is possible by using piezo scanner in scanning sample surface. In piezo scanner, piezo material is used to evaluate the height information of surface and trace it. High resolution scanning of surface is possible due to fine driving of piezo material.
In most of previous atomic force microscopes, linear PI controller is used to drive piezo scanner in scanning sample surface. But the driving target, piezo scanner, has nonlinear characteristics. To drive Piezo scanner faster, and eventually to gain high speed surface scanning abillity, a controller which has nonlinear characteristics may be needed. In this paper, fuzzy controller is proposed to fulfill this objective-to drive piezo scanner faster.
First, fuzzy modeling of piezo scanner is conducted. This fuzzy model is a kind of emulator of piezo scanner, and is used in evaluating controller's ability in simulation. Then, fuzzy controller for piezo scanner is constructed by genetic algorithm. Finally, performances of Pl controller and fuzzy controller was evaluated in fuzzy model of piezo scanner. And as a result, fuzzy controller shows better speed in controlling piezo scanner than PI controller.
With the result of this paper, I propose fuzzy controller for control of piezo scanner in atomic force microscope. It may make atomic force microscope faster than current systems.
