关键词: 磁悬浮系统, 非线性系统, 时变滑模, 悬浮气隙

Abstract:

In order to reach high-precision air gap of electromagnetic levitation grip a novel time-varying sliding mode was proposed. At first, a new exponential time-varying sliding surface was designed and guaranteed the sliding mode occurrence from beginning to end. The global robustness of parameter perturbation and external disturbance was realized. After that a control law of time-varying sliding mode was designed based on the sliding surface of exponential term and its stability was proved by the Lyapunov stability principle. Simulation results demonstrate that the time-varying term is introduced to improve the convergence speed of the sliding surface in the context of ensuring global stability of the system and to eliminate system chattering effectively.

Key words: electromagnetic levitation system, nonlinear system, time-varying sliding mode, levitation gap