Field Insights for Portable Vine Robots in Urban Search and Rescue

Abstract

Soft, growing vine robots are well-suited for exploring cluttered, unknown environments, and are theorized to be performant during structural collapse incidents caused by earthquakes, fires, explosions, and material flaws. These vine robots grow from the tip, enabling them to navigate rubble-filled passageways easily. State-of-the-art vine robots have been tested in archaeological and other field settings, but their translational capabilities to urban search and rescue (USAR) are not well understood. To this end, we present a set of experiments designed to test the limits of a vine robot system, the Soft Pathfinding Robotic Observation Unit (SPROUT), operating in an engineered collapsed structure. Our testing is driven by a taxonomy of difficulty derived from the challenges USAR crews face navigating void spaces and their associated hazards. Initial experiments explore the viability of the vine robot form factor, both ideal and implemented, as well as the control and sensorization of the system. A secondary set of experiments applies domain-specific design improvements to increase the portability and reliability of the system. SPROUT can grow through tight apertures, around corners, and into void spaces, but requires additional development in sensorization to improve control and situational awareness.

Figures (5)

• Figure 1: External view of SPROUT growing into the void space inside a mock collapsed structure. Orange arrow shows the direction of growth from outside the void. Transparent images depict robot pointing its sensor head in multiple directions. (Inset) Egocentric view of space using tip-mounted camera.
• Figure 2: Test locations on Massachusetts Task Force 1 rubble pile. We tested SPROUT at six locations on the mock collapsed structure rubble pile in Beverly, MA, each corresponding to different levels on the taxonomy of difficulty from Table \ref{['table:tod']}. The top and bottom rows of images present close-up views of the trial locations from the second field study (B) and the initial field study (A). Middle image is a birds-eye view of the rubble pile. Map data: Google 2024.
• Figure 3: Experimental setup for field studies. (A) The SPROUT system that we tested in the initial field study consists of a base containing the spooled vine body, a portable air compressor, and control electronics in separate cases. The operator controls the system with a joystick while viewing the tip-mounted camera stream on a screen, allowing safe operation if the entry point into the pile is unstable or hazardous. (Inset) View of SPROUT with tip camera removed showing the principle of growth by eversion. (B) Improved SPROUT system incorporating feedback from urban search and rescue team members and insights from the first study. System condenses control electronics into ingress-protected container which mounts to the top of the pressurized vine base. A Self Contained Breathing Apparatus (SCBA) tank provides compressed air to grow and steer the robot.
• Figure 4: Key findings from experiments. Without the camera mount, SPROUT steered in all directions and grew around sharp turns. With the mount, SPROUT had more limited tip mobility. With the hardware improvements between the field studies, SPROUT exhibited more capable maneuverability, faster growth, and more reliable teleoperation.
• Figure 5: System architecture for portable SPROUT operation. With improvements between field studies, SPROUT runs fully on battery power, features a condensed electronics and fluidic control system, and utilizes a joystick gamepad for control of the vine teleoperation.