Researchers at Caltech and NASA’s Jet Propulsion Lab have built a tube-launched drone that removes the standard requirements for takeoff conditions. The football-shaped foldable quadrotor is fired out of a cannon, unfolds itself, and then flies off.
SQUID – Streamlined Quick Unfolding Investigation Drone – gets its initial boost of 15 meters per second from a pneumatic baseball pitching machine, which gives the drone an apex of about 10 m. Immediately after the drone exits the launcher, a nichrome wire heats up and burns through a monofilament line holding the arms in place. Driven by springs, the arms snap out in just 70 ms, as the aerodynamic body of the drone passively orients it into the airstream. As soon as the motors spin up, SQUID automatically orients itself into a hovering attitude, and can then be controlled just like a normal quadrotor within less than 1 second of launch.
Working from the original three-inch model created last year, the new six-inch SQUID has an aerodynamic redesign for improved passive stabilization during launch and ballistic flight. The structural and aerodynamic changes that are required include having a high center of mass and deployable fins that keep the drone passively pointed into the airstream while also serving as landing gear.
Its hardware includes a camera (FLIR Chameleon3), rangefinder (TeraRanger Evo 60m), IMU/barometer (VectorNav VN-100), and onboard computer (NVIDIA Jetson TX2).
The ability to launch a drone from a tube brings a number of advantages: it’s fast to launch, safe to launch, can be launched from a moving vehicle, and can potentially be launched through objects such as tree canopies and power lines.
The results of the SQUID project were published in the paper, “Design and Autonomous Stabilization of a Ballistically-Launched Multirotor.”