High-accuracy position control over a large range using a macro/micro robot pair system with a magnetic levitation micro-robot

A macro/micro robot pair system with endpoint sensing has been suggested by many researchers in the robotics field recently as a means to circumvent the limited accuracy and speed of a conventional robot. Most of the work on robot pair systems has concentrated on developing a robust controller to solve the dynamic coupling problem which comes from the force interaction between the macro-robot and the micro-robot. We have developed a macro/micro robot pair system with a magnetic levitation micro-robot which is almost dynamically decoupled so that we can use a pair control strategy which uses each element's controller without modification. The macro-robot acts merely as a transportation system with high speed for the micro-robot which actually carries out the micron level task. The function of the proposed pair system mainly depends on the ability of the micro-robot itself rather than the pair control strategy, so we concentrate on developing a micro-robot which is suitable for the specific application of line tracking. We also discuss the general aspects of the micro-robot. The main goal of this dissertation is to show the feasibility of using the developed magnetic levitation micro-robot in a large workspace while maintaining its high accuracy. To do this experiment we have designed and built the macro-robot and micro-robot, integrated these robots, and devised special apparatus for verifying our achievement. We discuss each of these in this dissertation. A {dollar}pm{dollar}20 {dollar}mu{dollar}m tracking accuracy over an 8 cm range was demonstrated by the pair system. Note that the working range of 8 cm is limited by the test set-up, and the actual working range is the same as the macro-robot's workspace. Improvements of the pair system performance are also considered.