Development of a Fingertip Force Estimation System Based on a Mechanical Model Using Multiple Ring Sensors

Abstract

Quantitative evaluation of body movement is necessary in various fields, such as objective evaluation of patients' recovery progress in rehabilitation and skilled operations of technicians. In particular, hand movements play a significant role in daily life. In previous studies, a ring-type sensor that can estimate fingertip force by measuring tendon tensions without interfering with tactile sensations was proposed. In this paper, we expanded the mechanical model with one ring-type sensor on the proximal phalanx to the model with two ring-type sensors on the proximal and middle phalanges and evaluated the model's validity. To evaluate the model, we performed experiments to synchronously measure fingertip force, ring-type sensor outputs, and PIP and DIP joint angles. Applying the acquired data to the model and setting the appropriate parameters, it was confirmed that the fingertip force can be estimated with the proposed mechanical model. In the future, to improve the model, it is necessary to compare the estimation accuracy to the methods in previous studies that estimate fingertip force with ring-type sensors and to establish a parameter determination method.