Force Sensing Based on Nail Deformation for Measurement of Fingertip Force in Detailed Work

In this paper, we describe a method of measuring the force applied to a finger pad by attaching two strain gauges to the nail. We target sewing work at production sites. To measure the dexterous fingertip force work, we determine the position where the strain gauge is attached based on how the nails are distorted upon force application. Additionally, we devise a procedure for proper installation and removal of the proposed sensor. Then, we verify via experiments that the force in the shear direction can be measured and work needing fine fingertip force can be classified. In conclusion, the proposed sensor offers more detailed sensing than conventional sensors.