Three Degree of Freedom Magnetic Levitation Simulation with Zero Power Control.

Abstract

Typical machines include mechanical machine elements such as gears, bearings, guides, sleeves, and sliders, which require lubrication for proper operation. These elements wear during operation due to the contact surfac!}'> with relative motion to each other. Furthermore, lubrication chemicals and wear of the machine elements release particles contaminating the operating environments like clean rooms. Friction forces present in conventional machines can contribute to generating undesirable vibrations and noise, which could compromise acceleration and position, control. A magnetically levitated machines are an alternative to solve these problems and is a viable alternative for cleanrooms. If conventional machines are used in clean rooms, continuous cleaning is required. Magnetically levitated material handling systems offer no contact surfaces with relative motion to each other and therefore do not cause any contamination to the work environment as no particle release, friction, noise, vibrations and wear. Research and development of a magnetic levitation system to be used in cleanrooms requires expensive equipment. Approximate cost to fabricate such a research platform will be around 70,000USD. Therefore, it is difficult to perform research about magnetic levitation in developing countries. Magnetic systems are highly nonlinear and therefore simple linearized models and controllers are not suitable for advanced research. We are developing a nonlinear magnetic levitation system simulator with three degrees of freedom motion capability using commonly available software and presented in this paper. The proposed simulator can be used to design controllers for magnetic levitation systems without having to build an expensive physical prototype. Zero power control is a unique advantage which can be realized in magnetic systems. To achieve zero power control, the proposed magnetic levitation system uses hybrid electromagnets constructed using permanent magnets and electromagnets. The previous studies utilized LQR and LQI controllers to achieve zero power levitation control using 4 DOF platforms. Such 4 DOF systems require a mechanical joint on platform construction or a complex mechanical suspension system to achieve 4 DOF operation. However, the mechanical joint or suspension system is essential to achieve zero power control. The propos_ed magnetically levitated platform simulator utilizes four Hybrid Electro­Magnets (HEM) to achieve zero power-controlled levitation with 3DOF motion control and achieves similar results to 4 DOF control.