Design and precision construction of novel magnetic-levitation-based multi-axis nanoscale positioning systems

This paper presents two novel six-axis magnetic-levitation (maglev) stages capable of nanoscale positioning. These stages have very simple and ompact structures, which is advantageous to meet the demanding positioning requirements of next-generation nanomanipulation and nanomanuacturing. Six-axis motion generation is accomplished by the minimum number of actuators and sensors. The first-generation maglev stage, namely he -stage, is capable of generating translation of 300 m and demonstrates position resolution better than 2 nm root-mean-square (rms). The econd-generation maglev stage, namely the Y-stage, is capable of positioning at a resolution better than 3 nm rms over a planar travel range of mm× 5 mm. A novel actuation scheme was developed for the compact structure of this stage that enables six-axis force generation with just three ermanent-magnet pieces. This paper focuses on the design and precision construction of the actuator units, the moving platens, and the stationary ase plates. The performance of the two precision positioners is compared in terms of their positioning and load-carrying capabilities and ease f manufacture. Control system design for the two positioners is discussed and an experimental plant transfer function model is presented for the -stage. The superiority of the developed instruments is also demonstrated over other prevailing precision positioning systems in terms of the travel ange, resolution, and dynamic range. The potential applications of the maglev positioners include semiconductor manufacturing, microfabrication nd assembly, nanoscale profiling, and nanoindentation. 2007 Elsevier Inc. All rights reserved.