Abstract: A piezoelectric optimal feedback control methodology is provided to mitigate the superharmonic resonance of a flexible intelligent structure. Relationships among the feedback gains and the coefficients of vibration system and amplitude of excitation are obtained by using the stable conditions of superharmonic response for nonlinear vibration system. The regions of the feedback gain are obtained by using the stability conditions of eigenvalue equation. Attenuation rate is used to evaluate the performance of vibration control by taking the proportion of peak amplitude of free vibration for the suspension system with and without control. Taking the attenuation rate and energy function as objective functions and the regions of the feedback gain as constraint conditions, the control parameters of velocity and displacement feedback gains are worked out by using optimal method. It is found that a big feedback gain of velocity can lead to a small attenuation rate and has a good performance. The energy of the vibration system can be minimum by using the optimal feedback gains. The controller is designed to control the amplitude of super-harmonic vibration of intelligent structures. A experimental contro

Key words: nonlinear vibration;optimal control;super-harmonic vibration;piezoelectric;beam