A Novel Soft Shape-shifting Robot with Track-based Locomotion for In-pipe Inspection

With the advent of soft robotics the research community has been exploring how to exploit the inherent adaptability of soft elastic materials to overcome the limitations of systems based on rigid materials. A proof-of-concept design of a crawling robot for pipe inspection and preliminary analysis of its locomotion capabilities are presented in this work. The novelty of the proposed design is the combination of silicone based elements of different stiffness to enable global shape reconfiguration and whole-body track-based locomotion. The proposed system makes use of a plurality of multi-materials elastic tracks actuated by an on-board motor through a worm gear that pairs with all of them, causing their constant eversion from the inside to the outside of the chassis of the robot. Two toroidal inflatable chambers surround the chassis of the robot while passing through the loops created by the tracks. Upon inflation of the chambers the tracks are deformed, changing the overall diameter of the system. This feature allows the system to adjust to the local diameter of the pipe navigated, enabling also active contact force control between the tracks and the pipe walls. We demonstrate how the proposed system efficiently moves through rigid pipes of different diameters, both straight and curved, incrementing its outer diameter up to 100% of his original size. Maximum navigation speed and stall force applied are evaluated. With two front cameras embedded, the proposed robotic system can represent a cost-effective and easy-to-control solution for inspection applications, when adaptability and compliance are critical requirements.