A new analytical control strategy for a magnetic suspension system under initial position dispersions

Abstract

A nonlinear magnetic suspension system is considered in this paper. A novel online algorithm based on analytical approach is presented to stabilize the suspended mass. The new algorithm employs a single analytical function to create the ball position and velocity profiles. The reference ball position is described by a series of time dependent exponential functions. Boundary conditions at both initial and final states are automatically satisfied. Moreover, feasible ball position and velocity profiles are ensured by evaluating one algorithm parameter (an exponential factor). The exponential factor is analytically computed by minimizing the peak of electrical power. This new algorithm is capable of generating the well-suited coil voltage that guarantees the stability of the system with a small closed-loop command. Gain Shechting method is used to obtain the closed-loop effort in order to track the analytical reference profiles. Compared to the prior magnetic suspension algorithms, the proposed analytical scheme is qualified to handle very large dispersions in initial ball position while satisfying the ball position and coil voltage constraints. Monte-Carlo simulations with change in initial ball position are presented. The simulation results demonstrated the great reliable performance of the proposed algorithm despite the wide range of initial ball position dispersions.