PASSIVE AND ACTIVE CONTROL OF A COMPLEX FLEXIBLE STRUCTURE USING REACTION MASS ACTUATORS

Passive and active control have been performed on a flexible structure possessing complex modal behavior. Specifically, the structure has cl osely spaced modes which created a ''beat phenomena'' in the structure 's vibrations. Reaction mass actuators (RMAs) were used to suppress th e structural vibrations with both passive and active control schemes. The results of using both types of control systems were compared both analytically and experimentally. It was determined that, although pass ive tuning of the RMAs did suppress the structure's vibrations, additi onally applying active control to the optimally tuned RMAs did not sig nificantly increase the system's vibration suppression performance. Ho wever, by choosing the actuator's characteristics from active control considerations, an active strategy utilizing a local velocity feedback controller suppressed structural vibrations and reduced the active sy stem's settling time to 20 percent of the settling time with passive d amping. Both the passive and the active control were found to be a sig nificant improvement over the structure's open-loop response.