| Nanotechnology is playing a more and more important role in high performance materials preparation, micro-electric technology, biotechnology and aerospace engineering. To research the materials and structures in nano scale, it is necessary to study the Microcosmic surface detection technology, such as STM(Scanning Tunneling Microscope). Due to the requirement of high precision and fast response, piezoelectric actuators are usually used to drive the scanners of the microcosmic surface detection devices.An experiment setup was designed with driving system, tunneling current monitoring system, control system and vibration isolation system. Based on electrochemical corrosion technology, probes with radiuses of curvature of 40 nm on the tip were developed by membrane process. To detect tunneling current precisely, the monitoring circuit was designed with a two-stage amplifier and a fourth-order Butterworth filter. Besides, two control subsystems are separately developed for searching tunneling current and scanning samples. The subsystems combine inverse hysteresis model control and PID feedback control to improve the accuracy. Experimental results show that the relative positioning error of scanners decreases from 10.48% to 2.06%, relative error of detecting grating’s period declines from 12.50% to 0.05% and relative error of detecting gratings’ line width reduces from 13.69% to 0.18%. |
