Control of a magnetically levitated slider with nm-precision

Due to increasing demand in accuracy, the semi-conductor and optical disc mastering industry are looking for nanometer resolution vacuum compatible positioning systems. Magnetic bearings are ideally suited for this purpose, because here is there is no need for lubrication. The IU-module is a modular two degree of freedom mag-netic actuator for suspension and propulsion. The uniqueness of this actuator lies in the moving iron principle in which only iron is moving and there are no wires going to the moving body . With three IU-modules a six degree of freedom linear slider is constructed. The specifications for the slider are taken from the optical disc mastering industry , where the resolution of a single nanometer is required. To achieve nm-resolution close synergy between mechanical construction and controller design is needed. This paper shows the successful realization and controller implementation of a sub nanometer positioning slider system using the IU-modules.