A Soft Drone with Multi-modal Mobility for the Exploration of Confined Spaces

In post-disaster scenarios, rescuers are often confronted with the challenge of accessing confined and cluttered environments including long and narrow passageways, gaps in walls or ceilings. Because of their mobility and versatility, there is a growing interest in developing drones for the remote exploration of these dangerous and often difficult to access places. However, the mechanical design and locomotion strategies of current drones limit the size of the confined space that can be explored. In this work, we present a quadcopter capable of traversing long passageways 34% smaller than its nominal size. The combination of a soft morphing frame and multi-modal mobility allows the drone to exploit a new dynamic strategy for passageway traversal. The drone flies at a given speed towards the entrance of the passageway until it collides with it. The momentum and ability of the frame to soften allow the drone to passively fold and enter. Once the drone is squeezed between the walls of the passageway, it uses two tracks to crawl through. Through experiments, we characterize the main mechanical systems of the drone and study the entry into crevices of different sizes.