UAV Emergency Landing System
Project Summary
For the final in Mechanical Design, I worked with a team to build an unmanned aerial vehicle (UAV) capable of dropping off medications to remote islands. The plane was based on the XUAV Talon Pro Plane Body. We made alterations to this plane including replacing the servos, fixing parts damaged in transit, and fiberglassing the wing tips and belly of the plane to increase its durability.
In addition to the plane body, we designed, built, and tested a launch catapult, a payload drop system, a parachute to safely land the package, an arrestment system to safely catch the plane, and an emergency landing system.
In the project, my primary responsibility was to focus on the emergency landing system, which involved designing, prototyping, and testing various subsystems such as the bladder, sleeves, pressure vessel, and trigger mechanism. I also specked and ordered parts, fabricated the final system, connected the trigger to plane electronics, and extensively tested the trigger and inflation system to ensure maximum reliability before launch day.
Context
The UAV was designed to be used to distribute medical supplies to indigenous residents of islands off the coast of Maile and Canada. This could improve quality of life because pharmacies are not easily accessible to many of the remote islands so as people age they often have to move to the mainland to be closer to medical centers. Being able to directly send medications to residents could allow them to stay in their hometowns even as they age and require more medical attention
Video Demo
Our video demo shows successful independent testing of all subsystems, including launch catapult acceleration, handheld launch, mid-flight payload drop, parachute deployment, and safe recovery of the package using our arrestment system. We also demonstrate successful trigger and inflation of emergency landing airbags during ground testing. The primary challenge faced was interference between the plane and launch rail, preventing direct launch.
Emergency Airbags
The entire airbag system is constructed out of inexpensive and readily accessible parts which makes the design affordable and easy to work on which is especially important for a system that may take damage and thus might need repairs.
The Airbag system consists of a plastic soda bottle that acts as a pressure vessel and is housed in the plane and inflated to high pressure using a bike pump before flight. The airbag is able to be deployed by the operator by activating one of the auxiliary channels which punctures a membrane to allow the pressure in the bottle to equalize with the empty airbags which are mounted to the bottom of the plane. During tests, the airbag was able to inflate in 3-5 seconds which is hopefully enough time to inflate during a controlled emergency landing.
Components
Pressure Vessel
Repurposed soda bottle used as a pressure vessel to inflate airbags via an aquarium aeration valve, push-to-connect Shrader valve and zip tie.
Trigger
A Nichrome wire inserted into the connector melts the membrane between the bottle outlet and the bladders via when powered by the RC driver.
Airbags
Two long thin airbags on the bottom of the plane made of an airtight bladder housed inside a durable sleeve made of ripstop nylon.
Design Process
Prototyping
We investigated bladder shapes, materials, and methods for sealing. We also experimented with connection to multiple different pressure vessels.
Testing
We extensively tested the inflation system, and the nichrome trigger to ensure it would deploy and inflate on command. We iterated multiple times to prevent air leaks and we experinmented with different inflation pressures for the airbags.
Integration
We carved out space within the fuselage to fit the pressure vessel, attached the airbags to the plane body, and connected the trigger to the control board.
Full Project Report
The Team
During my time working on this project, I had the privilege of collaborating with a talented team of nine Olin students. Each team member used their skills and interests to contribute to the design of different subsystems. At the end of the day were able to successfully collaborate to get many interdependent subsystems to work.
