  Inflatable structures used in soft robotics applications exhibit unique
characteristics. In particular, the tip-extension structure, which grows from
the tip, can grow without friction against the environment. However, these
inflatable structures are inferior to rigid mechanisms in terms of their
load-bearing capacity. The stiffness of the tip-extension structure can be
increased by pressurization, but the structure cannot maintain its curved shape
and compliance. In this study, we proposed a mechanism that combines a skeleton
structure consisting of multi-joint links with functions to increase rigidity
while keeping low pressure and realizing the functions of bending and shape
fixation. We devised a design method for rigid articulated links and combined
it with a membrane structure that utilizes the advantages of the tip-extension
structure. The experimental results show that the payload of the designed
structure increases compared to that of the membrane-only structure. The
findings of this research can be applied to long robots that can be extended in
the air without drooping and to mechanisms that can wrap around the human body.
