Tendon-driven continuum robots are a class of soft robots that offer high flexibility and adaptability to complex, unstructured environments, surpassing traditional rigid-body robots in tasks requiring dexterity and safe interaction. However, their theoretically infinite degrees of freedom and underactuated structure pose significant challenges for accurate modeling and control. This project aims to address these challenges through the development of precise mechanical models and the exploration of advanced nonlinear control algorithms to enable accurate and responsive motion.
The illustration on the left showcases the first prototype developed in this project. It features a single-section silicone cylinder actuated by four tendon cables, each driven by a dedicated motor. The prototype is also equipped with an ArUco-based motion tracking system for pose estimation and integrated strain gauge sensors for tendon force measurement. This setup forms the foundation for ongoing model validation and control experiments.
The video to the right demonstrates the prototype performing a circular motion under closed-loop force control. The trajectory was generated using a finite element model based on Cosserat rod theory, from which the required tendon force profiles were computed. While the motion confirms the feasibility of model-based actuation, discrepancies caused by friction prevent the system from fully achieving the ideal path. Current efforts focus on integrating position feedback to improve tracking accuracy and compensate for unmodeled effects.
This project is funded by the German Research Foundation (DFG) as part of the DFG Priority Programme SPP 2100. We gratefully acknowledge the DFG’s support, which has enabled the development of our prototypes, experimental setup, and simulations. Their contribution has been essential to advancing research in the field of soft material robotics.
Contact
Tianxiang Dai
M.Sc.
Remco I. Leine
Prof. Dr. ir. habil.director