Modelling and Validation of a control System for a magnetic Levitation system

Abstract

Future missions for space-based experiments in gravitational physics require a drag-free Gravitational Reference Sensor. Such a setup requires a spherical test mass, where the position of the mass is determined by laser interferometry. The concept of using the surface of a levitating sphere as the measurement mirror for the interferometer has to be proven. Therefore, an inertial reference sensor is currently under development at Airbus Defence and Space GmbH. In this setup the sphere will be levitated through magnetic force. This thesis presents the development of the control system for the magnetic levitation setup, which consists of two current controlled electro magnets and two light barriers for the position estimation. Based on theoretical and practical investigations two controllers are designed from the identi�ed system model. Firstly a gain scheduled full state feed back controller and secondly a reduced order state controller is designed. As a result the experimentally evaluated controllers allow the sphere to oat in a range of 1mm with an error less then 1 �m. This allows the further investigation of the inertial reference sensor.