Optical fiber based sensor for angular measurement in rehabilitation

A specific articular exercise may be needed under particular circumstances in rehabilitation. In such cases, it is very important to quantify the angular kinematics of movements which are imposed to the patient in order to attain firstly, a possible well-adapted rehabilitation and secondly, a clinical follow-up. This research is originated from the lack of user-friendly, versatile and inexpensive apparatus which are commercially available. A study has been undertaken on the realization of versatile sensors, specifically for angular measurement using optical fiber. Its originality relies on applications of different scientific concepts. Following a significant bibliographic research, a geometric approach has been adopted in analyzing the power fading along the fiber due to its curvature. For the study of the light wave´s behaviour as a function of curvature and optical fiber angle, an automatic testing bench is constructed. Thus the sensed signal which is electronically processed represents an indirect measure of curvature angle. Finally, overall performances of the developed sensor are discussed with the experimental results