Active Control of a Flexible Structure Using a Modal Positive Position Feedback Controller

This study demonstrates the feasibility of a new Modal Positive Position Feedback (MPPF) strategy in controlling the vibration of a complex flexible structure us ing a single piezo-electric active structural member. The new control strategy generates its control forces by manipulating only the modal position signals of the structure to provide a damping action to undamped modes. This is in contrast to conventional modal con trollers that rely in their operation on negative feedback of both the modal position and velocity. The proposed strategy is very simple to design and implement as it designs the controller at the uncoupled modal level and utilizes simple first order filters to achieve the Positive Position Feedback effect. The performance of the new strategy is enhanced by augmenting it with a "time sharing" strategy to share a small number of actuators between larger number of modes.