BAM-STR: A Bio-Inspired Soft Tensegrity Robot Driven by McKibben Pneumatic Artificial Muscles

Tensegrity structures have lightweight, compliant, impact-resistant, and large-deformation characteristics, providing a deformable structural solution for mobile robots in complex environments. Inspired by earthworm peristaltic locomotion, this study proposes BAM-STR, a soft tensegrity robot driven by McKibben pneumatic artificial muscles. The robot adopts a three-layer, three-strut tensegrity structure, and the McKibben pneumatic artificial muscles are arranged at the diagonal and additional tendon positions to generate axial-radial coupled deformation under low-pressure actuation. A bio-inspired segmented peristaltic waveform control strategy is further designed. By sequentially activating and releasing the artificial muscles in the three tensegrity units, the robot generates an axially propagating deformation wave and achieves continuous forward crawling. Experimental results show that BAM-STR can achieve approximately 31% axial contraction and 21% radial expansion at an input pressure of 100kPa. When the control time interval is ΔT=1.0-1.25s, the robot reaches its maximum average crawling speed of approximately 6.5mm/s. Multi-scenario experiments further show that BAM-STR can adapt to channel widths ranging from 190 to 235mm, complete continuous crawling while carrying an additional payload of 200g, and maintain forward locomotion on a rough artificial grass surface. These results indicate that BAM-STR has path-width adaptability, load-carrying crawling capability, and rough-ground adaptability.