Characterization of Resistive Flex Sensor Applied to Joint Angular Displacement Estimation

The focus of this paper is characterize the limited operation of the resistive flex sensor for joint angle displacement estimation and the movement analysis. Resistive flex sensor is often used in wearable systems for estimating body motion and in this it was used to estimate the movement of lower limb joints in order to achieve human gait. The proposed characterization employs a 3D printed mechanical testbed with three different diameters, to bend the sensors, which measures the amount of bend and finds a correlation to the biomechanical joint movement. A proof-of-concept study involving a healthy subject was conducted to estimate the bend angle displacement of the knee joint angle for slow and fast movements. Accuracy and precision are evaluated for its application and combine with other devices, such as an IMU and an incremental encoder. The objective of this research is to evaluate a customized angular displacement sensor that will be used to measure in real-time joint angle displacements of an active lower limb orthosis developed at the UFRN Robotics Laboratory.