Development of Static Load Sensor utilizing both Direct and Inverse Piezoelectric Effect of Piezoelectric Element

Abstract

　It’s possible to measure static load using piezoelectric ceramics by sticking 2 pieces of identical ceramics together. When one of the ceramics is oscillated at its resonant frequency, the other ceramics generates voltage by following up to the motion of the actuator ceramics. When the vibration of the body is suppressed due to the impressed load, the sensor voltage drops according to the magnitude of the load. Vibration analysis proved that the configuration of the vibration of the sensor body is 1^st mode bending of a thin circular plate. It’s also turned out that the characteristics of the sensor voltage are dominated not by the magnitude of the load but by the contact area of the load with the ceramics. Therefore, introducing the cushion material between the load and the ceramics, which alters the contact area according to the magnitude of the load, will be able to control the sensitivity and the linearity of the sensor voltage to the load.