Design and Control of a Motion Decoupling Continuum Robot for Single Port Surgery

A topologically decoupled continuum robot is proposed for single port surgery, which realizes the decoupling between multi-segment actuation by designing an intermediate associated continuum segment. Meanwhile, the orientation of the end-effector only depends on the distal end segment, achieving the decoupling of position and orientation. Based on this motion decoupling configuration, the multi-segment continuum robot with six degrees of freedom is realized by designing a spatial cross-curved disk skeleton. The forward kinematics of the robot and the direct solution of inverse kinematics are then given. Finally, the experiments of actuation decoupling and trajectory tracking control are conducted. In tests, the average angular error of the robot decoupling motion is 2.39^o, and the tracking error at a speed of 20 mm/s without load is 1.46 mm. The experiment results show that the robot has good ability of actuation decoupling, and can realize motion control with stability based on the direct solution of inverse kinematics.