Triaxial force sensor with strain concentration notch beam for measurement of insect flight force

This paper reports on the triaxial force measurement during flapping flight of a fruit fly (Drosophila melanogaster). The total flight force was measured by a triaxial force sensor. The sensor consists of a cantilever probe, two sensing beams and four wiring beams. The total size of the sensor was 2 mm × 3 mm × 0.5 mm. A fruit fly was attached to the tip of the cantilever probe. The triaxial forces were measured when the fruit fly flapped. The measured force varied in synchronization with the flapping frequency of 240 Hz. The maximum forces in both lift and thrust directions were approximately 40 μN.