A novel shape detection method for continuum soft manipulator based on cable encoders

In this paper, a novel shape detecting method is proposed for continuum soft manipulator to detect the shape in real time, so as to achieve high-precision position and attitude control. The method uses three cable encoders to measure the length of the manipulator per section, and they are distributed at 120 degrees apart from the endplate of the manipulator. Based on the theoretical hypothesis that the soft manipulator has infinite degrees of freedom (DOF), the kinematic model for the single-section manipulator is developed by the piecewise constant curvature method. Further, the kinematic model is extended to the multi-section manipulator via improved D-H method, which achieves the mapping from the length information to the pose of the manipulator. Finally, the three-dimensional shape of the soft manipulator is simulated in real time by MATLAB, which verified the effectiveness of the proposed shape detection method.