Our paper on modelling, calibration, and evaluation of a tendon-driven parallel continuum robot was accepted for publication in the IEEE Robotics & Automation Letters. This is the first paper reporting on the results of our collaborative project with the Institute of Mechatronic Systems at Leibniz University Hannover, Germany funded in part by the German Research Foundation.
In the paper, we introduce a novel planar parallel continuum robot. Three kinematic chains are coupled and include tendon-actuated continuum segments. We derive the kinematics by adapting the model for a conventional planar parallel manipulator to include constant curvature bending segments. To account for friction and non-linear material effects, a data-driven model is used to relate tendon displacements and curvature of the continuum segments.
To calibrate the robot prototype, we identify geometric parameters for each kinematic chain and for the end-effector platform. The positioning repeatability is 1.0+/-0.3% w.r.t. a continuum segment length of the robot, and the positioning accuracy is 1.4+/-0.7%. In an open-loop control scenario, we achieve good accuracies in tracing circular and rectangular trajectories.
More details can be found here: https://doi.org/10.1109/LRA.2020.3010213