Development of an Ultra-Precision Positioning Stage Using an Opto-Mechatronic Component from a CD-ROM Drive

摘要

A positioning stage using a commercially available OPU (optical pickup-head unit) was constructed. An OPU contains all the key elements in a positioning stage, such as voice coil motors for the actuator, laser and photo diodes for 'the position sensor, and lens module for the moving stage. If an additional object carrier is rigidly mounted to the lens module and a small piece of CD is placed in front of the lens module, then the mounted carrier can carry light objects, such as bio-cells or optical fiber, and its relative displacement to the CD can be measured by the reflected optical signals from the CD. A digital lead compensator with integrator was implemented as the position feedback controller to achieve required positioning requirements. Experimental results showed that the positioning stage was able to follow different ranges of step commands, such as 2μm, 0.2μm and 50nm step commands, with required dynamic requirements. The conclusion is that the proposed positioning stage in this paper has high potential of providing a very cheap price for high precision positioning.