Performance of a six Degree-of-Freedom controlled moving-magnet planar actuator with a laser interferometer measurement setup

This paper concerns measurements with a nineaxes laser interferometer system, to determine the six-Degree-of-Freedom (DoF) performance of an electromagnetically levitated moving-magnet planar actuator with long-stroke capability in the plane. The new measurement system has 0.15 nm resolution over the full xy-stroke of 0.223 m × 0.223 m. The limitations on the attainable closed-loop tracking performance have been determined experimentally. The high performance measurement system has a negligible influence on this tracking performance. Consequently, the measured performance limitations are due to the actuator and the applied control method