A Parametric Multi-Bladed Continuum Robot Arm: Design-Family Construction and Locking-Free ANCF Static Modeling

Continuum robot arms offer compliance and confined-space dexterity that rigid-link manipulators cannot match, but each published design is built around a fixed structural configuration serving a single motion type, so that finger-like, planar, and spatial motion each demand a separate design and model. This work introduces a tendon-driven, multi-bladed continuum robot arm in which the blade count is a design parameter, together with a procedure that assembles the corresponding multibody model automatically for any blade count. Static response is modeled in the absolute nodal coordinate formulation using the fully parameterized BE24 beam element with the strain-split method, which alleviates the Poisson locking the element otherwise exhibits for the near-incompressible material considered. The static model characterizes force-displacement response, stiffness modulation by axial preload, and the reachable set of each variant. Blade count governs both the compliance of the arm and the dimensionality of the reachable set—a curve, a planar region, and a spatial surface for one, two, and three blades—and the three-blade set is trilobed rather than circular, reflecting pull-only tendon actuation. One construction and one modeling procedure thus span finger-like, planar, and spatial manipulators, and form the parametric model base for subsequent optimal design, targeted experimental validation, and inverse kinematics.