Active damping of a beam using a physically collocated accelerometer and piezoelectric patch actuator

This paper presents a theoretical and experimental study of the active vibration control of a simply supported beam using a piezoelectric patch actuator and a physically collocated accelerometer. Direct velocity feedback (DVFB) control is used to attenuate unwanted vibrations in a given frequency band. The performance of the control system is presented in terms of the total vibrational kinetic energy of the beam and compared to the fundamental limitation, for the particular actuator, by way of a feedforward control analysis. Since the sensor and actuator are not collocated in the control sense, the control system is only conditionally stable. The stability is also influenced by the actual control system electronics and the transducer dynamics, which results in even lower stability margins. It is shown in this paper that for a given electronics system and transducer arrangement, improvements can be made by inserting a concentrated mass at the sensor location so as to cause an additional roll-off of the open-loop frequency response function at higher frequencies. This improves the stability margin of the overall control system and hence permits a higher control gain.