Multivariable PPF Control of an Active Structure

This paper reports experimental implementation of extended positive position feedback (PPF) controller on an active structure consisting of a cantilevered beam with bonded collocated piezoelectric actuators and sensors. Stability conditions for PPF control are rederived to allow for a feed-through term in the model of the structure which is needed to ensure little perturbation in the in-bandwidth zeros of the model. The set of stabilizing PPF controllers is shown to be a convex set characterized by a set of linear matrix inequalities. A multivariable PPF controller is designed and successfully implemented on the structure.