Active vibration control of aerospace structures using a modified Positive Position Feedback method

A positive position feedback controller is modified and a new active vibration control technique is developed. Unlike the conventional positive position feedback, the new controller separates the damping and stiffness control using two parallel first order and second order compensators. The second order compensator has a damping ratio as low as the damping of flexible structure to provide periodic vibration control. Simultaneously, the high damping is made available through a first order compensator. The new controller is applicable to a strain-based sensing/actuating approach and can be extensively applied to piezoelectrically controlled systems. Control gains are obtained by performing the stability analysis. The controller is verified experimentally using a plate vibration suppression setup. The plate is controlled through two piezoelectric patches and its vibrations are monitored by ten sensors mounted on the surface of the plate. The results confirm that the new controller is able to provide good vibration reduction, with the ability to be used to simultaneously control more than one natural frequency.