Optimal Cable Arrangement Design for A Cable-Driven Continuum Robot with the Flexible Backbone

Cable-Driven Continuum Robots (CDCRs) with flexible backbones have been developed to perform dexterous manipulation tasks in various confined spaces due to their high flexibility and environment adaptability. A CDCR normally consists of a number of serially-connected identical Cable-Driven Continuum Joint Modules (CDCJMs). To produce large bending movements, a CDCJM often employs a parallel cable arrangement scheme, i.e., all of its driving cables are parallel to each other in its initial pose. However, such a CDCJM will suffer form the kinematics singularity in its initial pose, in which its flexible backbone will likely produce uncontrollable s-shaped deflection curves. To overcome such difficulties, this paper proposes a tilted cable arrangement scheme for the CDCJM. Considering symmetric arrangements of driving cables, a total of six tilted cable arrangement cases are investigated. Based on the structure matrices, the statics equilibrium equations are developed for the CDCJMs. To maximize the lateral force that the cable tensions of the CDCJM can sustain, the number of driving cables and the positions of cable attachment points are optimized. The simulation results indicate that the 2–2 cable arrangement is the optimal cable arrangement for the CDCJM.