Adaptive robust control of active magnetic bearings rigid rotor systems

Aiming at the problems of difficult decoupling, complex controller models, and poor disturbance rejection capability caused by the inherent nonlinear and strong coupling characteristics of the active magnetic bearing (AMB), an adaptive H-infinity robust control (AHRC) method is proposed in the AMBs-rigid rotor system. The proposed method combines the active disturbance rejection control (ADRC) with the robust control to achieve stable operation of the AMBs-rigid rotor system under high-speed conditions. First, a four-degree-of-freedom (4-DOF) AMBs-rigid rotor model was established and transformed into a one-degree-of-freedom (1-DOF) model for the design of the robust controller, which weakens the coupling effect between each of the degrees of freedom (DOF). Then the multi-objective non-dominated sorting genetic algorithm II (NSGA-II) was used to find the relative optimal weighting function value of the H-infinite robust control (HRC), which solved the difficulties in the design of the robust controller for known controlled system models. In addition, by combining the optimized H-infinity robust controller with the original error feedback control rate in the ADRC, the proposed AHRC retains the strong robustness of the HRC and the decoupling capability of the ADRC, which improves the tracking performance and anti-disturbance performance of the controlled system. Simulation and experimental results verify the effectiveness of the proposed method.