Robust vibration suppression in flexible systems using infinite impulse response digital filters

A method for vibration suppression is proposed, based on the preconditioning of any arbitrary input to the system, by using infinite impulse response filters. As shown theoretically, infinite impulse response filters can be used to suppress vibrations of flexible systems efficiently when they are properly designed. A new filter design tool is proposed to ensure this proper design: the robustness-error-delay curves concept. Based on these curves, filters with optimal vibration suppression properties can be parametrically predesigned independently from the specific dynamic system. As shown by the robustness-error-delay curves developed for conventional infinite impulse response filters, they meet a given set of specifications with a number of coefficients much smaller than that of other filter types, and thus, they allow the reduction of the computational effort and time, which may be crucial in the real-time filter implementation. It is shown, also, that infinite impulse response filters improve significantly the overall vibration suppression quality. At the same time, they maintain the simplicity and efficiency of the application of the existing preconditioning methods to any specific dynamic system. The vibration suppression properties of these filters are experimentally demonstrated, using a flexible aluminum beam attached to the end effector of a robot manipulator.