Dynamic modeling and experimental verification of a cable-driven continuum manipulator with cable-constrained synchronous rotating mechanisms

The cable-driven segmented manipulator with cable-constrained synchronous rotating mechanisms is a new type of continuum manipulator, which has large stiffness and fewer motors, and thus exhibits excellent comprehensive performance. This paper presents a dynamic modeling method for this type of manipulator to analyze the effect of the friction and deformation of the cables on the dynamical behaviors of the system. First, the driving cables are modeled based on the ALE formulation, strategies to detect stick–slip transitions are proposed by using a trial-and-error algorithm, and the stiff problem of the dynamic equations is released by a model smoothing method. Second, the dynamic modeling method for rigid links is presented using quaternion parameters. Third, the connecting cables are modeled by torsional spring–dampers, and the frictions between the connecting cables and conduits are considered based on a modified Coulomb friction model. Finally, numerical results are presented and verified by comparison with the experiment results. The study shows that friction and cable deformation play an important role in the dynamical behaviors of the manipulator. Due to these two factors, the constant curvature bending of the segments does not remain.