Experimental implementation of multivariable PPF control of active structures

This paper reports experimental implementation of an 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. This feed-through term is needed to ensure that the system’s in-bandwidth zeros are captured with reasonable accuracy. The set of stabilizing PPF controllers is shown to be a convex set characterized by a set of linear matrix inequalities. A number of multivariable PPF controllers are designed and successfully implemented on the structure.