Design of LQR-PID controller for linearized magnetic levitation system

A consistent framework for robust linear quadratic regulators (LQR), Proportional, Integral, Derivative (PID) controller has been presented. LQR is an optimal control method and PID control which are generally used for control of the linear dynamical systems. A new concept of controller which designed by two controllers working together has been presented in this paper, which results in formation of LQR PID. LQR-PID has provided robust stability and step reference tracking for the nonlinear system like Magnetic Levitation system (maglev). The nonlinear model of maglev system is obtained and linearized at the equilibrium point. Then the gains of LQR and PID controller are determined. Finally, Performance of this approach was investigated through simulation. Results prove that this control approach can stabilize the ball position and has appropriate disturbance rejection. Performance comparison between PID, LQR and LQR-PID has been also investigated.