Passive Shape Locking for Multi-Bend Growing Inflated Beam Robots

Shape change enables new capabilities for robots. One class of robots capable of dramatic shape change is soft growing vine robots. These robots usually feature global actuation methods for bending that limit them to simple, constant-curvature shapes. Achieving more complex multi-bend configurations has also been explored but requires choosing the desired configuration ahead of time, exploiting contact with the environment to maintain previous bends, or using pneumatic actuation for shape locking. In this paper, we present a novel design that enables passive, on-demand shape locking. Our design leverages a passive tip mount to apply hook-and-loop fasteners that hold bends without any pneumatic or electrical input. We characterize the robot's kinematics and ability to hold locked bends. We also experimentally evaluate the effect of hook-and-loop fasteners on beam and joint stiffness. Finally, we demonstrate our proof-of-concept prototype in 2D. Our passive shape locking design is a step towards easily reconfigurable robots that are lightweight, low-cost, and low-power.

Automated summary

Shape change allows for new capabilities in robots. This paper introduces a soft growing vine robot that can achieve dramatic shape change and utilizes a passive tip mount with hook-and-loop fasteners for shape locking without pneumatic or electrical input. Experimental results demonstrate the robot's kinematics, its ability to hold locked bends, and the effect of the fasteners on beam and joint stiffness. The passive shape locking design is a step towards lightweight, low-cost, and low-power reconfigurable robots.