A Musculoskeletal-Inspired Soft–Rigid Hybrid Tendon-Driven Continuum Robot with Integrated Friction-Aware Modeling and Experimental Validation

This work presents a musculoskeletal-inspired soft–rigid hybrid tendon-driven continuum robot (TDCR) designed to bridge the trade-off between positioning accuracy and safe physical compliance in contact-rich environments. The proposed system integrates a 3D-printed rigid backbone with a silicone overmolded layer, achieving a balanced combination of structural robustness, payload capacity, and compliant interaction. A friction-aware quasi-static modeling framework is developed, incorporating tendon routing, capstan friction effects, torsion, and external tip loading. Experimental validation demonstrates strong agreement between model predictions and measured behavior, with a tip position RMSE of 5.71 mm (5.95% normalized error). The robot maintains stable performance under payloads up to 20 g and exhibits low hysteresis (5.96 N·mm) and consistent behavior over 200 actuation cycles. The results highlight the potential of hybrid soft–rigid architectures for continuum robots in medical and human-interaction applications, offering a promising direction for achieving both precision and safety.