Passive limitations for a magnetic gravity compensator

The development of sophisticated advanced vibration isolation is important because even the minutest vibrations have disastrous effects on the performance of static and moving parts in high-precision machines. This paper concerns with the isolation of these vibrations for a large static body in an advanced micro-lithographic system, where a passive/active electromagnetic solution is presented. In these configurations passive permanent magnets (PM) provide the gravity compensation and active electromagnets the accurate positioning. This paper only considers the applicability of a passive magnetic solution for this high force gravity compensation application, or, more specifically, the influence of various PM array topologies on the force density. Further, fast-solving analytical models are presented and consequently are used to illustrate the feasibility of using passive permanent magnets for gravity compensation in this demanding high precision industrial application.