Firmness Evaluation of Apples Due to Excitation Using Dielectric Elastomer Actuators

Abstract

To assess the quality of fruits and vegetables, firmness is often used as quality-related index. Firmness is represented by firmness index that is defined by combining resonant vibration frequency with mass of fruits or vegetables. This paper shows the non-destructive measuring technique of frequency responses for apples via a vibration excitation by dielectric elastomer actuator (DEA). An advantage of DEA is its flexibility, so it is able to adhere directly to spherical objects like apples. Then, DEA’s excitation force is well transferred to the target. Vibration experiment was carried out, and we obtained the frequency response and firmness index of the apples to evaluate the quality of apples.