Development of an Optical Fiber Sensor for the Measurement of Angular Displacements in Anthropomorphic Systems

Due to the arising importance and widespread role of robotic systems, it is fundamental the development of high-performance position sensors. There are several existing methods to determine position of anthropomorphic manipulators. However, they present limitations, such as vulnerability to electromagnetic fields or application of mechanical load to the system. Concerning these problems, an optical fiber sensor based on microbending principle is proposed. The sensor system consists of a microbending optomechanical transducer attached to a multimode fiber which receives light emitted by visible laser source. The transducer causes perturbations on fiber, influencing the output light, which is acquired by a CCD device and then processed by imaging analysis tools. The obtained data was fitted by calibration curves correlating linear displacement and angle position with the normalized output light intensity. Moreover, the measured angle position was compared with the calculated one by computer, revealing an absolute error of ~5.4°. The optical fiber sensor presents a precise, feasible and low cost alternative to determine position of anthropomorphic manipulators and can also bring several benefits to robotics and automation industries.