Design, Validation, Prototype Development of a Miniaturized, Compliant Torque Sensing System for use in Exoskeletons.

Abstract

Exoskeletons for rehabilitation purposes are developed for use in physical therapy. Compliant torque sensors are needed in joints of Hand and Finger exoskeletons for accuracy and safe interaction. Spring-based series elastic actuation is popular for the soft mechanism of torque and force transfer between the exoskeleton and human fingers. Existing approaches for rehabilitation robotics use photo interrupters, encoders, magnetic encoders, optical encoders etc. having the complexity of assembly and increased size. In this research torque sensor is developed that accomplished the design requirements of stiffness, size, range, and linearity. The designs consist of an outer rim fixed and an inner rim to connect the moment arm for rotation. A single spiral link connects the fixed and the moving end of the sensor. Variation in the shape of the link is performed for better results. FEM Analysis is performed. Prototypes are implemented and validated.