A Distributed 3D Force Sensor for Detecting Insect Motion by Optically Evaluating Deformation of Microscale Grid Pattern Inscribed on A Flexible Hydrogel Sheet

摘要

To measure microscopic force smaller than 1 mN (0.1 gf), a distributed force sensor made of transparent flexible sheet is proposed, which is to be a useful tool for analyzing insect motion in biomimetics research. Inside the film, grid pattern of microscale pitch is inscribed using MEMS technology. Distributed force can be obtained by optically evaluating the deformation of grid pattern. The features are as follows: i) tiny distributed force can be detected in real time of video rate, ii) the force in not only vertical but also horizontal direction force with respect to the sensor surface can be detected, i.e., it is 3 axis sensor, iii) thanks to optical measurement, lots of wiring, such as in strain gauge or capacitive type tactile sensors, are not necessary, making the total sensing system simple, compact, and economical, iv) the hydrogel sheet composing sensor body including no electro wirings is highly biocompatible, making it suitable for insect force measurement. The force given by a mosquito leg was measured by the developed sensor.