Strain-based Cosserat dynamic control of soft manipulator

Accurate control of soft manipulators is challenging due to the complexity of their infinite-dimensional nonlinear dynamics. The Cosserat rod theory provides a robust framework for modeling the nonlinear deformation behaviors of soft robots. In this paper, a comprehensive insight into the strain-based Cosserat dynamic models is presented to facilitate the model-based controller design for slender soft robots. Based on the strain-based Cosserat dynamics, a general estimation-based dynamic control framework for the soft manipulator is proposed for the first time, and its corresponding implementation issues, such as control input boundedness and cable length-based control, are analyzed. The tracking performance of these controllers is evaluated through numerical simulations on a soft manipulator. Beyond the simulations, and thanks to the design and implementation of finite-time state estimator, experiments are carried out on a real soft cable-driven prototype to further validate the tracking performance of the proposed controllers. Comparative experimental results indicate that the estimation-based dynamic controllers enable accurate and fast tracking of the desired references for the slender soft prototype.