Observation of link deformations of a robotic manipulator with fiber Bragg grating sensors

More advanced robotic applications require high accuracy positioning of the robot manipulator. This paper introduces a novel approach to measure the elastic deformations of robot links in order to improve its pose accuracy. The paper develops a model of the fiber Bragg sensors that locally measure strain. In conjunction with an finite model of the link geometry this information enables the prediction of the arm deformation. The approach opens an avenue for more advanced position control, which considers the elastic link deformations. Both models provide the basis for a systematic analysis and optimization of the spectrometer, signal processing and sensor configuration. An evolutionary algorithm optimizes the sensor locations in order to minimize the predicted deformation error. The proposed scheme is verified experimentally on an industrial manipulator.