SITL: AirSim Simulator Support for ArduPilot SITL

[rajat2004]

This is an issue to keep track of the progress and for discussions with the community regarding my GSoC 2019 Project. Mentors are @tridge and @peterbarker
This post will be edited as and when progress is done on the project, new goals are set and important, relevant links such as issues, PRs, branches will be added so that everything is easily accessible from a single source

AirSim is a simulator for drones, cars and more, built on Unreal Engine. It is open-source, cross-platform, and supports hardware-in-loop with popular flight controllers such as PX4 for physically and visually realistic simulations. AirSim has been developed as a platform for AI research to experiment with deep learning, computer vision and reinforcement learning algorithms for autonomous vehicles.

A few important links -

• ArduPilot branch - https://github.com/rajat2004/ardupilot/tree/sitl-airsim
• AirSim branch - https://github.com/rajat2004/AirSim/tree/ardupilot-connector
  (No changes till now)
• Issue on AirSim for ArduPilot Compatibility - ArduCopter compatibility? microsoft/AirSim#65
  • Comment by Tridge about the possible approaches - ArduCopter compatibility? microsoft/AirSim#65 (comment)
• PR for ArduCopter Solo in AirSim: ArduCopterSolo support microsoft/AirSim#1387

Some relevant files in AirSim for reference -

• ArduCopter Solo API - https://github.com/microsoft/AirSim/blob/master/AirLib/include/vehicles/multirotor/firmwares/mavlink/ArduCopterSoloApi.hpp
• Default Settings - https://github.com/microsoft/AirSim/blob/master/AirLib/include/common/AirSimSettings.hpp
• Mavlink MultiRotor API - https://github.com/microsoft/AirSim/blob/master/AirLib/include/vehicles/multirotor/firmwares/mavlink/MavLinkMultirotorApi.hpp

Current Approach:

First, I'll create a backend (SIM_Airsim.cpp) in libraries/SITL which will be compatible with the Solo PR mentioned above. This will ensure that I'll be clear with the inner workings of AirSim & Ardupilot and their communication interface.
Depending on the response by the AirSim authors on the approaches outlined by Tridge in the comment, further actions will be updated here.
Currently, we're thinking of then modifying the AirSim backend for Solo to use Steppable Clock for implementing Lock-Step Scheduling.
After discussion, the backends can then be modified to either use Mavlink messages or to send data in a single packet in JSON or XML format.

Update: Initial SITL_AirSim files added, can be seen in the Ardupilot branch linked above

Feedback on the post and project is very much welcome!

[rajat2004]

Links for Ardupilot, Airsim branches added

[rajat2004]

https://discuss.ardupilot.org/t/gsoc-2019-airsim-simulator-support-for-ardupilot-sitl/42890?u=rajat2004

First blog post describing the project is up!

[rajat2004]

Closing this as no longer needed. Support for copter has been added and the documentation can be found here - http://ardupilot.org/dev/docs/sitl-with-airsim.html