A Novel Inflated Tube Robot With External Multimodal Shaping Joint Mechanism

Continuum robots recently have gained remarkable potential in exploring unstructured environments due to the merits of adaptability and flexibility. However, achieving flexible and steerable deformation in wide-range three-dimensional (3-D) spaces is still challenging for continuum robots. This article presents the design and control of a novel inflated tube robot with an external multimodal shaping joint (MMSJ) mechanism. The MMSJ works in conjunction with an electromagnetic switching element to exhibit multiple modes including crawling, spinning, and bending alongside the tube exterior by using only two motors, guiding the inflated tube to generate 3-D deformation. By developing the tailored apparatus to acquire the friction resistance in crawling mode and the torque threshold in bending mode, the proposed inflated tube robot is elaborately devised based on the parametrical analysis. Experiments on a real robot prototype demonstrate the capability of the devised robot in achieving steerable 3-D deformation with the maximal bending range at 130° and the fastest crawling rate of the MMSJ at 10 mm/s, which endows the potential for traversing and operating in 3-D diverse environments.