Analysis And Design Of Control System For A Magnetic Levitation Apparatus

In this paper, we study the nonlinear dynamic of ECP’s product Model730Magnetic Levitation (MagLev) apparatus, and use two methods of linearization(oneis linearization about operating point, the other is feedback linearization) get twolinear models.PD controller is designed for the linear models to analyzing the differencebetween two linearization methods. Close loop control rules are given by usingstate-feedback on the base of the linear models, the state-feedback signal of thesystem is not all can measurement so we design a state observer and use of theoutput signal to estimated speed state of the Mode730system.In addition, an external control loop with an PI controller is used to eliminatesteady state error. Due to Model730system exist friction forces (the state friction isnonlinear) and the integral effect of the controller, the system enter in a slidingcondition. In order to address this problem, we use a PI and PD switching controllerto eliminate the slip-stick effect, last given system real time response.The sliding-mode control is insensitive to system uncertainties anddisturbances when it is within expected limits, so we design an variable-structurecontroller based on feedback linearization model. Then use MATLAB/Simulink, toprove the feasibility of the control method. In order to eliminating steady state errorwe add an integral factor to control system. Real time results showing the controlsystem performance are included. The discrete exponential reaching law approach isused in designing the discrete-time variable-structure controller, which is existingsteady state oscillation. Thus an adaptive discrete variable structure controller isdesigned. Real time results showing the control system have good dynamic qualityand stability.