The project started by learning and using software simulations in order to understand the fundamentals of the drone, sending code to and from, as well as learning about the Pixhawk ecosystem, and most importantly MAVlink and MAVros messages. Important software used were;

• QGroundControl

• Gazebo

• Visual Studio Code (code editor)

MAVros is a ROS package that enables MAVlink (Micro Air Vehicle) messages to be sent and received between compatible devices, initializing communication between devices.

QGroundControl (QGC) is a critical software for any drone application, as it provides full flight control over the drone, as well as calibrating, altering important drone parameters, and general drone checks over MAVlink messages.

Gazebo, an open-source 3D robotics simulator, was used in parallel to the actual drone with the PX4-Autopilot package installed, to simulate a quadcopter model into an open-world environment running MAVros. Because uploading and testing code on the actual drone was a lengthy process, being able to upload the code to a simulated environment cut our prototyping time significantly.

Visual Studio was used as our code editor for both C++ and Python, in order to code programs that would allow for autonomous flights in OFFBoard Mode on the drone.

Procedure before any flight

A procedural routine is done each time before either a manual or autonomous flight and it includes;

• Turning on and calibrating the OptiTrack Mocap system (external vision system) :

  • includes calibrating with wand, setting ground plane, creating a rigid body, and finally broadcasting data over internet

• Attach lipo battery to quadcopter to turn on the onboard computer, flight controller, and power to motors :

  • Here's the list of packages needed to be run by the onboard computer in order to initialize communication between all components;

    • roslaunch mocap_optitrack mocap_px4.launch

    • roslaunch mavros px4.launch

• Now a check is done to ensure everything is running accordingly;

  • Launch RVIZ (can be done remotely), and ensure there is a local position topic being published, and it follows the position of the drone as you move it manually

Manual Flight is simply achieved through a handheld radio controller, which communicates to the radio receiver connected to the Pixhawk (see wiring diagram);

• Un-flip the kill switch

• Arm the drone

• Raise throttle to takeoff

Autonomous Flight is conducted in the drone's "OFFBoard" mode, where the vehicle's movement is controlled autonomously. The purpose of the code we developed was to;

• Autonomously arm -> enter offboard mode -> take off -> fly to given coordinates around the room ->ensuring it is at those coordinates -> return to home -> land -> and auto disarm

• The code is run on a remote pc and the drone runs the code over MAVros

The gazebo simulated environment tremendously cut down code prototyping times, as it mimics real-life drone flight almost identically, letting us run the code in SITL before real life.