Self-Tuned Optimum Control of Hybrid Foil Magnetic Bearing
摘要
Hybrid foil magnetic bearings (HFMBs) are high-speed and high-precision bearings which use foils and electromagnetic fields to levitate a rotor. It is a nonlinear system and in previous works, linear controllers were used by researchers based on mathematical approximations. This linearization of a nonlinear system hinders its efficient performance, and the application of a nonlinear controller can help in achieving its full potential. However, expert knowledge and experience are necessary for designing such controllers. To eliminate the need for expert knowledge, this paper introduces the design of a self-tuned fuzzy logic controller which is able to achieve the stable operation of HFMB with the help of different meta-heuristic algorithms.
MethodsThe controller algorithm involves the combination of Mamdani type-2 fuzzy logic control with Particle Swarm Optimization and Pattern Search algorithms. The application of the proposed methodology resulted in the generation of rules from a blank rule base along with the upgraded input and output membership functions.
ResultsThe validation of the present methodology against the two literature results shows reductions in vibration along the x-axis by 21.26% to 55.04% and along the y-axis by 59.80% to 61.07%. Further, the error bar analysis indicates the variation in the rotor trajectory is lesser than 0.8% of the nominal air gap. The findings indicate that the designed controller performs better than a manually tuned fuzzy logic controller in the presence of initial deviation (almost zero steady-state error) and rotor mass uncertainty (-67.22% overshoot), along with better computational efficiency.
ConclusionThe proposed framework facilitates the development of a self-tuned optimal controller for HFMB. Integration of Mamdani type-2 fuzzy logic control with Particle Swarm Optimization and Pattern Search algorithms results in 30.87% better computational efficiency. Also, it is capable of handling rotor positions for both trained and untrained data.