抄録
This paper interprets the techniques on application of piezoelectric sensors and actuators. The fundamental equations of piezoelectric materials are first explained. As application examples the piezoelectric materials used as an actuator for high-density recording magnetic head and used as a sensor for medical diagnosis are described. Further, the piezoelectric material worked both as a sensor and an actuator is applied for monitoring and assessment of the health conditions or damage occurrence in large structures. Finally, a technique using self-sensing feedback circuit to improve the hysteresis behavior of piezoactuators is introduced.