Hysteresis-assisted shape morphing for soft continuum robots
- Zheyuan Bi
- Tianchen Ji
- Sanja Dogramadzi
- Soo Jay Louis Phee
- Jiajun Liu
- Wenjie Lai
- Diyang Wu
- Bing Zhang
- Lin Cao
2025-10-15
Conventional robots require more actuators for greater dexterity, increasing design and control complexity. We introduce a hysteresis-assisted shape-morphing (HasMorph) paradigm for soft continuum robots and integrate with tip-everting soft-growing robots. Unlike conventional approaches that avoid hysteresis, HasMorph intentionally exploits friction-induced shape hysteresis, the difference in robot shape during loading and unloading, to enable numerous reversible shape changes using only two sequentially controlled actuators via an inverted zigzag tendon-sheath mechanism. Integrated with tip growth, the robot achieves complex, reversible morphologies and frictionless follow-the-leader navigation. Mechanics and kinematics models reveal how friction and input sequences govern shape evolution and expand the robot’s configuration space. Experiments validate dexterous morphing and robust navigation in unstructured environments. HasMorph enables direct, fine-grained actuation of hyperredundant soft bodies with minimal actuation, offering a scalable approach to soft robot design. This paradigm opens avenues for minimally invasive surgical tools and adaptive inspection systems in complex, confined spaces.