Active Torsional Vibration Control Experiments Using Shear-Type Piezoceramic Sensors and Actuators

In this article, active control of pure torsional vibrations using piezoelectric shear-type transducers is discussed Pure torsional vibrations can be sensed and controlled by incor porating these transducers into tube-type structures. The effects of changing the electrode orientation with respect to the polarization direction of the shear mode transducers is discussed. Two types of shear mode piezoelectric transducers-ring-type with tangential polarization and shell-type with axial polarization-are examined. In other words, the piezoelectric constant d ₁₅ is utilized. Different sizes of phenolic and pyrex tubes are employed in this experiment Since the sensor signal is proportional to the rate of change of the angular displacement, a velocity feedback control technique is ap plied. The time domain responses for the first mode, and fre quency domain responses for the first three modes, are demon strated. Individual and simultaneous control for the first three fundamental modes, respectively, have been successfully obtained.