Static Model Assisted Stereo-Visual Shape Sensing of Flexible Manipulators

Wire-driven flexible manipulators are widely used in medical interventions and most of them are controlled in open loop. Their closed-loop control relies on shape sensing, which is challenging. In this paper, a shape sensing method for two-dimensional flexible manipulators based on Statics Model and Bezier curve is proposed. This method builds on the statics modeling of the flexible manipulator and the assumption that the deformed shape is close to a Bezier curve. By employing the motion and tension of the wires together with one or more joints' locations measured by a stereo vision system, the manipulator shape can be well estimated. Compared with purely vision-based method, this method applies to wider conditions, including visual occlusion. The proposed method is experimentally validated. Results show that for both load-free and loaded conditions this method could well estimate the shape of the flexible manipulator.