Papers by Author: Chao Jung Chen

Abstract: The objective of this research is to develop a PC-based closed-loop nanopositioning system using the dual-frame two-axis drive single mobile independent framework. The stage body was supported by an air bearing on a granite base to reduce the frictional force. The developed stage was driven by the PC-Based interface of ANCA 5DX CNC controller, for the precision motion control of the linear motors. The laser scales were used as the feedback sensors so that the closed loop control of the developed system was possible. Based on the test results, the designed closed loop nanopositioning system was capable of precision positioning within the travel of 100 mm along X-axis and Y-axis. The Z-direction stage stability of the developed system was 20 nm, the maximum yaw error of the stage moving along X-axis was about 3.77 arc-seconds, and the maximum pitch error of the stage moving along Y-axis was about 1.04 arc-seconds, based on the test results. By utilizing the PC-Based interface of ANCA 5DX CNC controller based closed-loop PID control system, the positioning capability of X-axis and Y-axis was about 20 nm. Performing the circular test with radius of 20 mm, the deviation of circular positioning test was about 223 nm. Based on the tracing speed test results, the standard deviation along X-axis and Y-axis was 5 nm under tracing speed of 0.05 mm/min.

Abstract: Precision positioning is an essential basis for precision mechanical engineering, such as positioning for precision manufacture, or positioning control of robot arms. Due to the increasing demand for precision in the submicrometer range, precision positioning plays an important role for precision manufacture. In this investigation a nano-positioning stage is developed. With the positioning system, high precision positioning and large displacement range can be achieved simultaneously. Advantages of this developed system are positioning driver with single actuator, uncomplicated mechanical structure, low cost and lower hardware requirement. A laser interferometer is used for displacement measurements of the translation stage, and a mini-autocollimator serves as angle sensor for tilt angle measurements. The tilt angle can be minimized with piezo translators and control operations. By the displacement measurements of laser interferometer, the feedback control is performed for positioning in large travel range. High precision positioning in nanometer-order can be achieved with the positioning system. With this development, individual sensor modules are self-accomplished and dominating technologies for the complete nano-positioning system are established.