Biomimetic tapered soft manipulator with precision and load-bearing capacity

Designing a soft manipulator that effectively serves human applications presents significant challenges, especially in motion robustness and accuracy. The elephant trunk, with its flexibility, strong load-bearing capacity, and dexterous yet soft tip, provides an inspiring model. Inspired by the elephant trunk's thrust-deformation mechanism under multi-muscle action, we present the design principles of a composite tendon and pneumatic hybrid-driven tapered soft manipulator (TSM). Simulation and testing show that the TSM achieves a repeatability accuracy of 0.69 ± 0.43 mm and single-axis errors below 2 mm. With a 2-kg load, it maintains less than 37 mm of deformation in all poses. Additionally, the TSM reduces contact pressure by 35.7% through active softening. These results highlight the manipulator's strengths in motion stability, load-bearing capacity, and safety during human contact, showcasing its potential as a flexible limb for mobile or humanoid robots.