Laboratory model of a magnetic levitation system

Abstract

The magnetic levitation consists of balancing the forces of attraction and repulsion of a ferromagnetic object located in a foreign magnetic field in such a way as to keep a desired distance between the object and the magnet. This technology is receiving increasing attention because it helps to eliminate the frictional losses due to the lack of mechanical contact. This makes it possible to reduce the wear of critical machine parts and achieve high speeds with increased positioning accuracy. Advanced applications include the high-speed Maglev trains, magnetic bearings and suspension, electromagnetic cranes, high-accuracy positioning of wafers in photolithography in the manufacturing of integrated circuits, and other high-precision contactless positioning devices. Positive results are also observed in applications from the mining and processing industry in the extraction and processing of raw materials, which makes the topic relevant. The paper presents a laboratory model of a single degree of freedom electromagnet-based system intended to aid the studying of the effect of magnetic levitation. The possibilities for the implementation of different positional feedback types are discussed together with the power circuit that drives the electromagnet. A mathematical model and implementation of a fully digital algorithm that uses the PID control law are presented. Experiments are conducted that could aid in building a sensorless control system. The elaborated laboratory model allows for easy upgrade and can be used in disciplines in the field of measurement, control, and automation as a whole.