Optoelectronic Shape Sensing for Flexible Robotic Applications

Abstract

Shape sensing in continuum robotics enables stable actuation and control, as estimation of complex curvatures is essential for manoeuvring through complex environments, for applications in the manufacturing, aerospace, and medical industries, as well as space and rescue operations. This paper demonstrates the performance of an optoelectronic based shape sensing system integrated into a two-segment tendon actuated robotic manipulator. The sensing principle is proximity-intensity based sensing and utilises a convex shaped reflector for modulation of proximity during rotation in two degrees of freedom. For improved sensing performance, the shape sensing system utilises a simplified circuit design with features such as power switching properties for elimination of signal interference effects and for significant reduction in consumption of power, as well as inclusion of low friction tubes along the tendon routing paths, for reduced friction during large bending motions. A new streamlined technique for the calibration of the sensors is demonstrated, and a validation of the shape sensing performance shows improved estimates of tip position and orientation as well as shape of the robotic structure.