drone-unity-sim

A Unity simulator for the drone team's PX4 aircraft. Unity simulates the physics, sensors and cameras; PX4 SITL connects to it over the same MAVLink HIL interface it uses with Gazebo and flies the vehicle. QGroundControl, ROS 2 (over uXRCE-DDS) and MAVLink scripts talk to PX4 unchanged.

Vehicles are described in JSON specs (Assets/StreamingAssets/vehicles/) and built when the sim starts. Two are included: PX4's X500 quadcopter and a quadplane standing in for the team's aircraft. tools/px4_airframe.py generates the matching PX4 airframe from a spec.

Documentation is in the wiki: Setup, Architecture, Development. The pages live in docs/ and are published to the wiki when they change on main, so edit them there in the same pull request as the code they describe.

Quick start

Requires Unity 6000.6.0f1 and a PX4 v1.17.0 SITL build (see Setup).

1. Open the project in Unity, open Assets/_Project/Scenes/Flight.unity and press Play. It flies the X500 by default.

2. From the PX4-Autopilot directory:

   PX4_SIM_MODEL=none_iris ./build/px4_sitl_default/bin/px4 -d

3. The overlay in the Game view changes to PX4 SITL: connected lockstep=on.

4. Fly it with QGroundControl, or from the project folder:

   pip install pymavlink
   python3 tools/px4_flight_test.py hover

For the quadplane, set Vehicle to quadplane on the VehicleLoader component of Managers (or pass --vehicle quadplane to a built player) and start PX4 with PX4_SIM_MODEL=gazebo-classic_standard_vtol.

Layout

Path	Contents
Assets/_Project/Scripts/	The sim: PX4 bridge, vehicle physics, sensors, ROS publishers
Assets/StreamingAssets/vehicles/	Vehicle specs: mass properties, rotors, wing, control surfaces, sensor mounts
Assets/Editor/DroneSim/SceneBuilder.cs	Generates the flight scene
Assets/StreamingAssets/sim_config.json	Camera topics, frames, resolution, rate and format, read at startup (editable in builds)
Assets/Tests/EditMode/	Unit tests
tools/px4_flight_test.py	Scripted hover or VTOL flight through PX4, with pass/fail exit codes
tools/px4_airframe.py	Generates a PX4 SITL airframe from a vehicle spec
missions/	QGroundControl mission for the quadplane