Add SITL target for starting airsim

[Jaeyoung-Lim]

Describe problem solved by this pull request
Previously, to run Airsim with PX4 SITL both simulations need to be run separately. The steps involve multiple steps and creates confusion always when starting / closing each processes on multiple terminals.

Also, since SITL is run completely independent of Airsim, it is hard to enforce which models were supported or not. Currently only the iris model is supported.

Describe your solution
This PR sets a make target that automatically starts Airsim when it is stored somewhere as a package. The procedure is as the following.

• Down the latest Linux distribution and one of the environments of Airsim: link Lets assume, we have downloaded the most simple Blocks environment
• Extract the zip file
• Run the following command to specify the runscript

export AIRSIM_APPLICATION_PATH=<path_to_blocks>/Blocks/Blocks.sh

• Run the following target to start airsim and px4 sitl

make px4_sitl airsim_iris

Additional context
The latest Airsim release does not include the latest lockstep fixes, therefore we need to wait for a new release from the Airsim side. Expected ETA <1 week as of microsoft/AirSim#2477

[hamishwillee]

That's cool. Does this work on all platforms - and what happens if it is not supported/available?

We should add this information to:

• http://dev.px4.io/master/en/simulation/airsim.html
• http://dev.px4.io/master/en/setup/building_px4.html#make_targets - the viewer section
• Anywhere else?

We also need to make it clear that the simulation is very heavyweight.

@Jaeyoung-Lim @julianoes We currently link to "external" instructions in http://dev.px4.io/master/en/simulation/airsim.html
Is this working for us/is it time to move these into our own instructions.

New link? https://microsoft.github.io/AirSim/px4_sitl/

[Jaeyoung-Lim]

@hamishwillee I believe so, but it would be dependent on what gets released on the Airsim side.

Once Airsim has a new release and we can check that it is functional, we should move the instructions internally. I guess the instructions are external because we never wrote it down properly?

[hamishwillee]

Once Airsim has a new release and we can check that it is functional, we should move the instructions internally. I guess the instructions are external because we never wrote it down properly?

The instructions are external because it was developed by microsoft and it was never clear how the work would be maintained. That kind of still isn't clear. If we're going to support this, is there any way to get some basic testing done on CI (e.g. just to check that it can be set up and build successfully?)

[bkueng]

• What is the restarting / ctrl-c behavior? Is there a way to restart px4 w/o restarting the heavy-weight simulator?
• Shouldn't startup also update the json config file?

[Jaeyoung-Lim]

@bkueng

• ctrl-c closes both px4 and airsim. Would it be possible to restart only px4 without affecting the simulator?
• Since this is running a binary release, we don't need to configure the json file

[Jaeyoung-Lim]

@hamishwillee I think thats a good point. We should definitely check this in CI. I will see what we can do about this. I think just checking if upstream master works with Airsim properly will be enough

[bkueng]

Would it be possible to restart only px4 without affecting the simulator?

That's what I'm asking you. The simulator needs to handle it. As it's a TCP connection, it knows then the px4 goes down.

Since this is running a binary release, we don't need to configure the json file

Ok, so changing to a HIL config would not be possible either?

[hamishwillee]

OK, keep me posted re CI. I'll try track this and think about docs when it is done. Feel free to ping me though in case I miss it.

[julianoes]

@Jaeyoung-Lim this is cool but I'm concerned because the airsim releases on GitHub are outdated and don't support lockstep. The Linux one is so old it crashes due to a "wrong" mavlink message. If we are to support that we also need to have builds or build instructions available, right?

[bys1123]

@julianoes good news, AirSim 1.3.0 just released.

[bys1123]

Looking forward airsim_px4_vision

[Jaeyoung-Lim]

@bys1123 Airsim can only support one airframe, which is mapped to iris. This is a limitation coming from airsim

[bys1123]

Thanks for explains.

[julianoes]

@julianoes good news, AirSim 1.3.0 just released.

Oh that's awesome!

[bys1123]

This link is broken, should be https://microsoft.github.io/AirSim/px4_sitl/ now.

[hamishwillee]

@Jaeyoung-Lim Are you saying we need to update our links to Airsim docs to https://microsoft.github.io/AirSim/px4_sitl/ "now"? Irrespective of other changes in this PR?

[bys1123]

@hamishwillee microsoft/AirSim#2507 . Not related other changes I guess.

[bys1123]

I’m trying to run PX4 1.11 (w/ cygwin toolchain) + AirSim 1.3.0 on windows
I got this waring:

pxh> WARN [commander] Takeoff denied! Please disarm and retry
WARN [PreFlightCheck] Preflight Fail: Compass Sensor #0 missing
WARN [PreFlightCheck] Primary compass not found
WARN [PreFlightCheck] Preflight Fail: Accel Sensor #0 missing
WARN [PreFlightCheck] Primary accelerometer not found
WARN [PreFlightCheck] Preflight Fail: Gyro Sensor #0 missing
WARN [PreFlightCheck] Primary gyro not found
WARN [PreFlightCheck] Preflight Fail: Baro Sensor #0 missing

my settings.json:

{
   "SettingsVersion": 1.2,
   "SimMode": "Multirotor",
   "Vehicles": {
       "PX4": {
           "VehicleType": "PX4Multirotor",
           "UseSerial": false,
           "UseTcp": true,
           "TcpPort": 4560,
           "ControlPort": 14580,
           "params": {
               "NAV_RCL_ACT": 0,
               "NAV_DLL_ACT": 0,
               "LPE_LAT": 47.641468,
               "LPE_LON": -122.140165,
               "COM_OBL_ACT": 1
           }
       }
   }
}

[Jaeyoung-Lim]

@bys1123 I believe that the issue is caused by PX4/PX4-SITL_gazebo-classic#411
The multirate sensor publishing should be added to the Airisim side

[Jaeyoung-Lim]

Closing as stale