| description abstract | Abstract. Soft and continuum robots have unique advantages and capabilities useful in medical applications and confined environments due to their highly flexible structure. However, their underactuation and theoretically infinite degrees-of-freedom present significant challenges, particularly in control and state estimation. Prior work showed that a 2D discrete rod mechanics model, derived from the continuous partial differential equations of a Kirchhoff rod and expressed in maximal coordinates, can facilitate continuum robot state estimation and feedback-linearization-based control without conversion to a classical minimal robot dynamics form. We here extend that maximal-coordinate modeling approach to 3D, in a symmetric, constrained-Lagrangian form, using quaternions and Baumgarte constraint stabilization. We also formulate a physically intuitive, model-based observer to estimate the full state of a continuum robot by introducing virtual forces and moments. We validate both the open-loop model and the observer through optical tracking in experiments on a large tendon-driven continuum robot prototype, demonstrating the ability to accurately estimate the robot’s dynamic state during actuation. | |
