On controlling the response of primary and parametric resonances of a nonlinear magnetic levitation system

In this paper, a proportional-derivative controller is proposed to reduce the horizontal vibration of a magnetically levitated system having quadratic and cubic nonlinearities to primary and parametric excitations. A second order approximate solution is sought using the method of multiple scales perturbation technique to clarify the nonlinear behavior for both amplitude and phase of the system. The effect of feedback signal gain is studied to indicate the optimum values for best performance. Validation curves are included to compare the approximate solution and the numerical simulation. A comparison with previously published work is included.