Fuzzy logic based modal space control of a cantilevered beam instrumented with piezoelectric patches

摘要

In this paper, a control law for controlling the vibrations of a cantilevered beam is established Using fuzzy logic based independent modal space control and fuzzy logic based modified independent modal space control. The effect of this modification is that an actuator is never called upon to apply effort which is beyond safe limits and the operator does not have to calculate control gains. The inputs to the fuzzy logic based control are the modal displacements and modal velocities of the modes to be controlled. A fuzzy rule base consisting of nine simple rules based on modal displacements and velocities is used. The controller is implemented experimentally on a test beam and the first two modes are satisfactorily controlled. The experimental set-up consists of a cantilevered beam on which a piezoelectric sensor-actuator pair is fixed near the root, in a collocated fashion. For experimental implementation, the size of the problem is reduced using a modal reduction technique. Modal displacements as well as the velocities of the first two modes are observed using a real time Kalman observer. Real time implementation of fuzzy logic based control has always been a challenge because a given set of rules has to be executed in every sampling interval. Results in this paper establish the feasibility of experimental implementation of the fuzzy logic based controller presented for active vibration control.