Passivity-Based Control And Its Application To The Electromagnetic Levitation System

Passivity-based control(PBC), which is based on the viewpoint of energy, is a important method of nonlinear control. It is able to take full advantage of structural characteristics of the systems. In the paper, the controller for the electromagnetic levitation system is designed by the PBC way and its effects are analyzed. The whole design process is divided into the procedures of system modeling, controller design, performance analysis and parameters determination.The same model for current-controlled system are made by two different ways. One way is modeled by mechanical equilibrium and voltage balance, the other is modeled by Lagrange equation. Then the advantage and practicality of the flux-controlled system are analyzed, and the model of flux-controlled system is made and used for systemic analysis and design.During the controller design the model is transformed to the hamilton system, and a partial differential equation(PDE) is got by the assignments of damping, interconnection and total energy. The control law is able to be obtained by solving this PDE. For the system isn't very complicated, a method is presented to solve the PDE directly. The control law obtained by this method has the advantage that the physical meaning of its parameters are clear. Then a control law is obtained and explained.The parameters of the controller will influence the performance of the system, so it's a important problem in the design of systems to adjust parameters to satisfy the requirements of the system performance. First the influence of the parameters is analyzed, then the ways to determine the parameters are proposed and verified by the simulation of the system.