Soft-CCD Algorithm for Inverse Kinematics of Soft Continuum Manipulators

To date, soft robots have been increasingly designed and analyzed, especially, Soft Continuum Manipulators (SCMs). Due to dexterous deformability, their Inverse Kinematics (IK) is still difficult to solve. Cyclic Coordinate Descent (CCD) algorithm is one of the classical optimization algorithms to solve IK of rigid manipulators with prismatic or rotational joints. However, it cannot be directly extrapolated to SCMs with configuration space parameters such as center arc, bending angle, and torsion angle. Here, we modified the CCD algorithm from a new view and proposed several tricks to set constraints. Numerical and experimental results show that the soft-CCD algorithm can quickly and accurately generate solutions for IK of SCMs. This study provides the necessary kinematic foundation for fault tolerance, obstacle avoidance, trajectory planning, and other further explorations of SCMs.