The purpose of this project is to develop a multi-Unmanned Aircraft System (UAS) system, or swarm, to provide a faster and safer method to survey a radiation plume following a nuclear blast. Current methods require soldiers to walk into dangerous radiation fields with hand-held detection devices, potentially exposing them to harmful doses and hazards. A team of West Point cadets developed a UAS swarm system to provide automated remote sensing of radiation sources and hazards. First, the swarm segments the expected radiation plume into survey lanes, and dynamically adapts assignment of these lanes based on radiation readings shared in real-time.  Second, the swarm self-divides a road network and conducts a visual reconnaissance along routes to automatically identify hazards, like obstacles or vehicles, to inform movement decisions in the operational area. Data from the swarm is fused in real-time into a radiation heatmap and map of road blockages.  The UAS consist of Tarot 650 frames custom integrated with a Pixhawk flight controller and an Odroid Linux computer.  This allows UAS to integrate with the 2017 Service Academy Swarm Challenge framework which enables distributed control. This paper focuses on the challenges and solutions to mechanically configure the heterogeneous swarm for its multi-mission purposes, as well as how to transport and launch the swarm rapidly to meet expeditionary needs.

            The UAS must be rapidly configured with payloads for its two swarm missions.  To accomplish this, a universal battery holder was designed and 3D printed.  This component has a locking rail mechanism to enable rapid tool-free swap of various payloads.  These include (1) a Hermes radiation detector to provide radiation counts and spectroscopy, and (2) a Logitech C270 camera and Jetson Nano Graphics Processing Unit to perform image classification for route reconnaissance.  The battery holder also houses a SF11 laser-rangefinder to measure height above ground. The design minimizes weight and shift in center of gravity to reduce negative impacts on flight endurance.  The paper will include details of the design, as well as compare modeled versus actual flight-tested endurance results.  

The team also developed a solution to transport and rapidly launch drones for their mission. The rapid launch subsystem consists of a set of interconnectable boxes, each housing and securing a UAS during transport. One to four individual boxes are mounted to a central base which provides power, command and control, and integration with a radiation response HMMWV vehicle. The base may be adapted to allow mounting on a variety of vehicles, and the modularity of the design allows for the swarm size to be expanded if needed.  An Arduino microcontroller runs the functions of the box and receives a wireless command to remotely open the box and unlock the UAS for launch.  When this occurs, an electronic latch is triggered releasing the spring-hinged lid to open while servo motors securing the drone legs also swivel open.  In addition, the rapid launch system provides persistent power to the UAS during transportation so that it can remain on and ready without draining its flight battery. A set of diodes and properly selected voltage sources in the box and onboard the UAS allow power to automatically flow from the box when the drone is physically docked, but also seamlessly transition to the onboard battery when the it disconnects on liftoff. A custom printed circuit board was developed to configure the base with greater simplicity and reliability. 

Each feature of this project increases the usability, speed of deployment, and simplicity of UAS swarm that can be utilized in complex challenging environments that are prohibitive for human access.  The systems in this paper were all designed, built, and are being flight tested.  The final paper will include results of those tests, lessons learned, and recommendations for future iterations of this work.


Rapid Configuration and Launch of a UAS Swarm for Post-Nuclear Blast Response

Division / Sponsors: 
Aerospace, Bioengineering, Applied Mechanics, Design Engineering Division, Advanced Energy Systems, Manufacturing Engineering Division, Noise Control and Acoustics, Nondestructive Evaluation, Diagnosis, and Prognosis (NDPD), Nuclear Engineering Division, Process Industries Division, Fluids Engineering, Heat Transfer, Materials, Microelectromechanical Systems, Safety Engineering and Risk Analysis, Computers & Information in Engineering


Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2020/volume/84478

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