Study On Piezoelectric Self-Sensing Actuator In Space-Sharing Mode

A single element, simultaneously functioning as a sensor and an actuator can be termed as self-sensing actuator(SSA). SSA has advantages in implementing true collocation, increasing control stability, decreasing system volume and weight, optimizing system design. SSA have potential application in vibration control, health monitoring, damage detection , system identification and MEMS.At present, piezoelectric SSA is paid more attention in the field of SSA and a majority of people emphasize particularly on decoupling approach. There are bridge circuit based SSA approach and observer based SSA approach. Besides, this paper proposes space-sharing SSA approach. The aims are just as: (1) space-sharing SSA is served as not only sensors of displacement but also actuators of displacement. (2) space-sharing piezoelectric SSA is applied in active vibration control of flexible structures.In this paper, theory and application of space-sharing piezoelectric SSA are studied. The main works are as follows. (1) Based on bilateral electromechanical transducer theory, piezoelectric transducer is modeled by transfer matrixes of bilateral transducers that gives a perfect explanation of space-sharing based SSA approach. (2) The real equivalent of space-sharing piezoelectric SSA is set up and simulated with PSpice software and it is showed that electrostatic coupling is introduced by parasitical capacitance C_c and the smaller of C_c the smaller of electrostatic coupling (3) With ANSYS software, dynamic analysis is carried and it is showed that the amplitude and phase versus frequency of each node on the cantilever is consilient. (4) Space-sharing piezoelectric SSA is made by dividing the electrode of one piezoelectric ceramic wafer into sensing and actuating sections using lithography and the actuation and sensing effects are studied, ulteriorly, a method to determine the electrostatic coupling is proposed with the property of beam on the anti-resonant frequencies. (5) The feedback control system is designed on Lab View software, including system identification of piezoelectric cantilever, control design. It is clearly showed that space-sharing piezoelectric SSA is effective to detect and suppress vibration in the results of vibration control experiments.