Robust Adaptive Control of Medium-low Speed Maglev Based on Magnetic Nonlinearity

Abstract:

In order to ensure the suspension stability of maglev trains， we investigate the suspension control problem of medium-low speed maglev vehicles under the disturbances of nonlinear magnetic fields and track irregularity in this paper. Firstly， the dynamic and static magnetic field characteristics are analyzed based on the finite element method， and a suspension force model considering magnetic saturation and eddy current effects is established. A mathematical model of a single suspension unit is built on the basis of the suspension force model. Then， a robust adaptive control method is proposed， which flexibly adjusts the control parameters through the adaptive law in the framework of generalized PI control. The Lyapunov method is used to prove that all signals in the closed-loop system are ultimately uniformly bounded. Finally， simulations under various operating conditions are conducted on the whole vehicle dynamics model to verify the effectiveness of the proposed control method. It is shown that air gap tracking errors under the robust adaptive control are both reduced by over 70% under sine and random disturbances， and compared with the traditional PID control， the maximum differences of air gap tracking errors between the front and rear suspension points of the same suspension module decrease from 1.571 8 mm and 1.227 8 mm to 0.195 2 mm and 0.396 2 mm respectively under the condition of vertical curves.

Key words:maglev vehicle;magnetic saturation;eddy current effect;robust adaptive control