Design and Analysis of a Metamorphic Hexapod Robot for Inspecting Curved Cavities Inside the Aircraft

The inspection of curved cavities inside the aircraft is one of the necessary items before the flight. However, due to the complexity of their internal environment (narrow cavities, complex curved surface, etc.), maintenance personnel needs to climb into the aircraft for visual inspection. This paper presents a new metamorphic hexapod robot named HBot, which is mainly applied in inspecting curved cavities inside the aircraft. It reduces the overall size and increases metamorphic mechanisms through a well-designed mechanical structure. Gaits and motion strategies are proposed and analyzed, namely hexapod crawling, quadruped crawling, obstacle-crossing, and single-leg actuating motion. Then, the motion strategies of the model are simulated and analyzed by ADAMS and Python software. Experimental results demonstrate that the HBot can run in target environments with different motion strategies. Specifically, it is capable of hexapod crawling on sloped pipes with varying curvatures, utilizing quadruped crawling to pass through curved cavities in aircraft, overcoming obstacles such as steps, and performing single-leg actuating motions. Results show that HBot has good comprehensive capabilities of surface adaptability and motion stability.