Tahereh Taleshian - Electrical Engineering Dept. Babol University of Technology, Babol, Iran
Farzaneh Akhgari - Electrical Engineering Dept. Babol University of Technology, Babol, Iran
Abolfazl Ranjbar Noei - Electrical Engineering Dept. Babol University of Technology, Babol, Iran

In this work, an electromagnetically levitated vehicle prototype is controlled. The vehicle levitation is achieved through the control of the gaps of the electromagnets. The system is open loop, unstable and highly nonlinear with a very restrict equilibrium region. In this paper, two robust controllers are designed and compared. A sliding mode control is applied for increasing robustness, modeling uncertainties and reducing disturbance responses, while LQG/LTR controller is one which allows the designer to shape the principal gains of the return ratio at either the input or the output of the plant, to attain robust stability and performance specifications. The simulation results show that the closed-loop system provides robust stability, while having good tracking and disturbance rejection and noise attenuation.

Electromagnetically Levitated Vehicle; Sliding mode control; LQG ، LTR design; Kalman filter; Performance and Robustness