Kinetostatic Modeling of Tendon-Driven Parallel Continuum Robots

Tendon-driven parallel continuum robots consist of multiple individual continuous kinematic chains, that are actuated in bending utilizing tendons routed along their back- bones. This work derives and proposes a Cosserat rod based kinetostatic modeling framework for such parallel structures that allows for efficiently solving the forward, inverse and velocity kinetostatic problems. Using this model, the kinematic proper- ties such as reachable workspace, singularities, manipulability and compliance of tendon-driven parallel continuum robots are studied in detail. Experiments are conducted using a real robotic prototype to validate the derived modeling approach. Overall, a median pose accuracy of 4.9 mm, corresponding to 3.4% of the continuum robots’ lengths, and 6.2◦is achieved. The median of the model’s computation time results in 0.51 s on standard computing hardware. Fast computations of below 100 ms can be achieved, if an appropriate initial guess for solving the kinetostatic model is available, making the model suitable for a range of different applications including optimization or control.