Novel Hybrid Positive Feedback control for active vibration suppression in flexible structure

A new controller is introduced in this paper as a novel approach toward active vibration suppression in flexible structures. Hybrid Positive Feedback (HPF) uses a second- and a first-order compensator that are fed by displacement and velocity feedbacks, respectively. Parallel pairs of the HPF controller are implemented when suppression in multimode condition is issued. Since the controller uses two gains for each pair of actuator/sensor patched of each mode, an optimized gain selection task is essential. Hence, H₂ and ℋ_∞ optimization approaches are utilized to provide the best level of suppression using the HPF controller. Numerical simulations and a set of experiments are implemented to evaluate the performance of the controller. Comparison of the HPF controller result with the Positive Position Feedback (PPF) method demonstrates the superiority of the new method. HPF controller using either of the optimization methods attenuates the vibration displacement amplitude to at least 85% of the uncontrolled amplitude. However, best result is achieved using the ℋ_∞-optimized process as the net value of vibration displacement amplitude caused by a multimode disturbance is reduced by 90% of the uncontrolled displacement amplitude.