Embedded Files
Overview
Overview
This design uses a 3D printed fixture that clips below the drone onto an existing gimbal intended for attaching cameras. This brings the inlet of the tube to below the propeller rotors so that is is collecting well mixed air. The tubing is then clipped to the legs of the drone to prevent stress put directly in the fixture. On top of the drone are a Raspberry Pi 4, sensors and an external battery pack for power. The fixture is composed of acrylic pieces stacked using standoff spacers. Sidewalls protect the Pi and battery but leave the sensors to open air. The Pi communicates with a device on the ground by SSH using its onboard wifi.
Main Components
Main Components
Tubing fixtures
Drone Flight + Documentation
Sensors
Communication
Supported Fixture
Supported Fixture
Holds tubing under propeller for collecting mixed air
Connects to existing camera clicking mechanism in camera gimbal
Hose clamp holds tubing in place on fixture
3D printed from nylon carbon fiber
Swagelok Fixture
Swagelok Fixture
Secondary, simplified option
Clamps onto Swagelok of tubing using nut and screw
Relies on stiffness of Synflex to bend into position under the propellers
3D printed from nylon carbon fiber
Electronics and Mount
Electronics and Mount
Composed of Raspberry Pi 4 and barometer, humidity, and temperature sensors using I2C connections
Mounted to acrylic sheets that stack using standoffs that screw into existing mounting holes
Levels can easily be removed/added
Powered by separate battery pack for independence
Pi enclosed for protection while sensors open to air for accurate readings
Communication and data logging
Communication and data logging
Program to log data onto local drive for download and analysis after test
Using on board wifi to SSH into Pi and control remotely
Terminal outputs live data to SSH terminal for researchers to see data during test
Testing and Analysis
Testing and Analysis
Testing was done to verify the effects of weight on the flight time of the drone and then compared to the given DJI data. Real world conditions were found to lower the over all flight time as shown on the left. In addition, the flight time is lessoned by the need to land the drone prior to complete battery depletion. This means that the full 40 minutes the researchers were hoping for are less feasible and require some experimental changes.
FEA Simulations
FEA Simulations
3D Printed fixtures were tested both experimentally and in finite element simulations using expected load values. Failure occurred at the tabs attachment piece for both pieces with a worst case scenario test of ~900 g and with Nylon Carbon Fiber as the material.
Factor of safety ~6.46
Factor of safety ~8.55
Performance
Performance
20220524_133719.mp4
The drone system was successfully flown at SIO on May 24th, 2022. The drone easily achieved altitudes of 28.5m before being limited by the tubing length. Sufficient flow rate was achieved by the pump system indicating that the design solution was successful in meeting its top priorities and air flasks can be collected and well aspirated by the drone. On the left shows the the pump system connected to the tubing as well as two flasks that are filled up with the sampled air.
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