Why is so important this post? because all the knowledge acquired from this project has been influenced for all the experience and opportunities resulted from the hard work done. Four people and friends joined me to create, build, and fly this amazing vehicle. The next lines will describe some engineer aspects, also experiences from the design to the catastrophic crashes flights.
From the politics of the university and the career, most of the developments are supported on open-source codes, tools, and technologies. The design of this drone was selected by the budget available so in the market there are flight controllers really expensive with great performance but not open-source, like DJI A3 Controller and DJI Naza 2, in the other hand we can find Pixhawk and Ardu-pilot open-source hardware controller, in terms of performance Pixhawk is like DJI best controllers but also is expensive, then we had to use Ardu-pilot. The below diagram shows the main parts and technology used for the drone, composed of two communications, RC control, and Telemetry.
One of the great benefits of Ardu-pilot (APM) is the capability to be controlled with python code using MavLink communication protocol, there are libraries available like DronKit also supported on ROS for better performance and communications, this allows the quick integration of Linux Embedded computer like Raspberry pi, Nvidia Jetson Nano or Nvidia Jetson TX, it gives the possibility to have a big brain to decide, store algorithms for start researching in autonomous vehicles.
The mechanical design of the frame was thanked in a modular resistant sketch with X type of frame configuration for load applications, most of the drones built at college was with wood and some soft materials, listening to the suggestions from students we decided to use aluminum to manufacture the main piece of the vehicle, the most lightweight 3 mm aluminum type in the market and also the most malleable. For the propellers was selected the 10 inches with a protection design in 3 mm impact polyethylene. Some calculations are omitted for informative proposes.
The complete manufacture was done in FabLab center, with 3D CNC milling machine, the design was done in Solid Edge ST10 and the CAM program was in Autocad Fusion 360, some images are presented in the mechanical fabrication. For the electronics, the APM chosen was 2.8 with Neo-6M GPS, 3DR Radio Telemetry 915Mhz, 4 Cells 5000 mA lithium battery and FlySky radio controller.
APM has some issues with the control algorithms, frequently lose RC communication as well as stability, this problems resulted in 2 crashes, one happened at 10 m of altitude while it was landing but a high speed for control lost communication and the other in take-off near to the roof. With this flight controller, the college participated in two contests, one at National University of Colombia, and the other with the Sena - Unicentro Flight contest.
Some other modifications, as well as computer vision implements, were done on Nvidia Jetson nano for aerial shooting research proposes. Finally, the future of this implementation uses autonomous algorithms with SLAM and planning. This project is one of the most important that I have done, gave me the possibility to assist a Drone Fundamentals Course at Centro de Investigaciones en Óptica in México, also I did my final degree research in computer vision algorithms for aerial vehicles in the same place.