Experiments on a magnetically levitated planar actuator

This paper discusses experimental results of a moving-magnet planar actuator with integratedmagnetic bearing called the Herringbone Pattern Planar Actuator (HPPA). Both open-loop measurements of the commutated planar actuator as well as measurements of the closed-loop dynamic performance of the operational actuator are included. Smooth switching between different sets of active coils is used to enable long stroke motion in the xy-plane using a special commutation algorithm. The constraints imposed by the current amplifiers in combination with the commutation algorithm result in complex, position dependent, worst-case acceleration constraints. Therefore, a novel method is presented to derive the worst-case acceleration specification in the xy-plane, as a function of position and current amplifier constraints.