Self-Tuning Control for Magnetic Bearings

Auto-calibration and auto-tuning for a magnetic bearing system of an industrial turbo-molecular pump (TMP) is presented. The control program is able to calibrate and levitate a system autonomously and then to fine-tune the controller according to some desired stiffness-damping characteristics. Practical issues on auto calibrating are discussed. The basic time constants of the plant are determined automatically in order to find a first stabilizing control autonomously. The tasks of the designer are 1.) to make the choice of operating ranges of all the components and to match those ranges and 2) to give a realistic goal on desired stiffness and damping. Other fine-tuning criteria and autonomous determination of stability ranges of feedback parameters are also investigated.