An FBG-based sensing glove to measure dynamic finger flexure with an angular resolution of 0.1� up to speeds of 80�/s

Abstract

We demonstrate a fiber Bragg grating (FBG) sensor-based highly accurate instrumented glove that can measure finger flexure with an angular resolution of 0.1�. The sensing unit consists of an FBG that is very sensitive to axial strain induced by the flexing of fingers. The spectral shift of the reflection spectrum of the FBG varies linearly with the joint rotation angle. The sensor offers a very high angular resolution of 0.1� with a very high sensitivity of 18.45 pm/degree. The accuracy evaluated using a mechanical setup and the human hand is 0.13� and 0.67� respectively. This is much better than many other reported sensors. The sensor showed excellent repeatability with a maximum standard deviation of 0.30� and 0.79� on a mechanical setup and the human hand respectively. The results are validated using a pre-calibrated inertial measurement unit (IMU) sensor. The sensor also exhibited much better dynamic response compared to the IMU up to a rotation speed of 80�/s. These results demonstrate that our sensor is a strong potential candidate for the development of high-accuracy instrumented gloves that could be used to monitor the progress in the rehabilitation of stroke survivors. This work focuses on the careful characterization of the sensor to establish it as a sensitive and practical approach. The accuracy, repeatability and dynamic response were evaluated using a motorized mechanical model of a finger joint and also on the hands of two human subjects.