Design and control of a 6-DOF high-precision integrated positioner

This work presents the design and control of a high-precision 6-degree-of-freedom (6-DOF) multi-dimensional positioner. This high-precision positioning system consists of a novel concentrated-field magnet matrix and a triangular single-moving platen that carries three 3-phase permanent-magnet linear levitation motor armatures. With a combination of six independent force components, the moving platen can generate any 6-DOF motion. Three aerostatic bearings are used to provide the suspension force against gravity for the system. We designed and implemented digital lead-lag controllers running on a digital signal processor (DSP). To improve the dynamic performance in the vertical direction, we implemented a controller in the feedback path as well. Currently, the positioner has a position resolution of 20 nm and position noise of 10 nm rms in x and y and 100 nm in z. The angular resolution around the x-, y-, and z-axes is in sub-micron order. The planar travel range is 160 mm /spl times/ 160 mm, and the maximum velocity achieved so far is 0.5 m/s with 5-m/s/sup 2/ acceleration in the y-direction, which is highly suitable for semiconductor manufacturing applications. Several 2-dimensional motion profiles are presented to demonstrate the stage's capability of accurately tracking any extended planar paths.