Fuzzy fractional sliding mode control of magnetic levitation system of linear synchronous motors

Aiming at the control performance of linear magnetic levitation synchronous motor (LMLSM) suspension system, a fuzzy fractional sliding mode control method was proposed. According to the voltage equation, flux equation and motion equation of LMLSM suspension system, the magnetic levitation force equation and the state equation of the system are derived; The integral sliding mode surface was constructed to ensure the global robustness of the system, and the low order term of error was introduced to make the state variable converges to zero in finite time. In order to weaken the chattering aggravation caused by the introduction of integration, fuzzy reasoning was used to estimate the switching gain. The fractional order system was introduced to construct a new type of fractional integral sliding mode surface and reaching rate, which has higher stability and weakens the chattering effect of the system compared with the integer order. Finally, the simulation analysis shows that compared with PI, integral sliding mode and integral fuzzy sliding mode, the regulation time of no-load start is reduced by 37.5%, the dynamic landing is reduced by 88.9% and the recovery time is reduced by 50%. The control strategy has the advantages of small steady-state error, short regulation time and recovery time, strong immunity and reducing chattering. © 2022, Harbin University of Science and Technology Publication. All right reserved.