Position Precision Control of Magnetic Levitation Systems Based on Generalized Multiple Disturbances Estimation and Compensation

This paper presents a generalized multiple disturbances estimation and compensation based position precision control of maglev systems, especially for the estimation and compensation of the unknown periodic disturbance. In order to accurately track the periodic reference and estimate the periodic disturbance, the internal model of periodic signals is embedded into the design of the generalized disturbance estimator (GDE) and the outer-loop controller, respectively. Meanwhile, the adaptive period estimator (APE) is designed to ensure the good estimation accuracy of the periodic disturbance when the period of the disturbance varies in a small range. Then, the disturbance estimate and its derivatives are introduced into the control law, and the disturbance compensation gain are designed to eliminate the influence of mismatched disturbances on the output. Finally, the stability and anti-disturbance performance of the proposed method are analyzed, and the effectiveness of the proposed method is verified by simulation and experiment.
Note to Practitioners
—For the maglev systems, there are many types of disturbances, such as constant, sinusoidal and periodic disturbances. If these types of disturbances are simply considered, the good control performance will not be achieved. For this reason, a generalized multiple disturbance estimation and compensation based position precision control is proposed in this paper, with special attention to the estimation and compensation of periodic disturbance, whose period varies in a small range. The internal mode of periodic signals and the proposed APE are employed for the design of disturbance estimation and the modified repetitive control (MRC). Then, the disturbance compensation gain is designed to solve the adverse effect of the mismatched disturbance for the maglev systems. Simulation and experimental results verify the effectiveness of the proposed method. The reported idea of generalized multiple disturbance estimation and compensation can also be extended to control of other types of systems with multiple disturbances.