Design Of The Implicit General Predictive Controller For The Maglev System

The levitation control system is a key technique of the maglev system. The traceability and robustness of the suspension controller are mostly concerned. Based on the single-electromagnet control system model, an Implicit Generalized Predictive Controller(IGPC) is proposed in this dissertation. As for the step problems, when the maglev train runs across the step of the railway, the performance of the proposed controller is investigated. Compared with the state feedback controller based on the feedback linearization, the fluctuation of the electromagnet can be greatly attenuated using the IGPC controller.The main contents of this paper are organized as follow:Firstly, the model of the single-electromagnet control system is built, and the stability of the open-loop system is analyzed. The state feedback controller is designed based on the feedback linearization method.Secondly, different types of the railway steps in the maglev guideway are listed. The performances of the PID controller, when dealing with these steps, are analyzed by simulation. Due to these analyses, the difference between the measured levitation gap and the average levitation gap is the main issue that should be concerned. The GPC algorithm is proposed to solve this problem.Thirdly, to solve the issue of unexpected fluctuation of the electromagnet when it comes across the railway steps, the Implicit General Predictive Controller is designed. The GPC algorithm cannot be directly utilized in the levitation control system because of its instability and rapidity. Thus the cascade control method is adopted. The nonlinear feedback linearization is employed as the inner-loop which guarantees the stability of the controller, and it pre-stabilizes the levitation control system. The linear CARIMA model is also obtained. The Implicit Predictive Control is designed as the outer-loop, which enhances the traceability of the controller. The simulation results of the levitation control system running across the railway steps Indicate that the IGPC controller with the hierarchical control has better performance compared with the feedback linearization controller.In conclusion, the proposed IGPC controller is an implementation of the GPC algorithm for the levitation control system. The study in this dissertation shows that the proposed controller is more robust when solving the problem of the electromagnet passing across the railway steps.