Influence of sheet roughness on the sensitivity of piezoelectric force sensors

Abstract

Piezoelectric force sensors are widely used in precision measurement and machining applications. Sensitivity is one of the significant parameters determining the precision of these sensors. The influence of factors, such as the piezoelectric coefficient, sensor structure, and temperature on sensitivity had previously been studied except the roughness of sheets. For design optimization, the effect of roughness on the sensitivity of piezoelectric force sensors was investigated. A sensitivity model was built based on the electromechanical relationships and measurement systems. Fractal theory and classic statistics model were used to define the roughness of the sheets. The stiffness effect and thickness effect were used to probe the relationship, and two types of experiments with sheets of different roughness were performed to verify the models. The results indicated that the roughness of the sheets affected the sensitivity of the piezoelectric dynamometers due to the stiffness effect and thickness effect. In terms of the thickness effect, rough sheets induced high sensitivity; however, in terms of the stiffness effect, as the roughness decreases, the sensitivity first improved and then decreased. A method was proposed to optimize the roughness of the sheets to improve the sensor performance.