kwikius / fg_ext_fdm Goto Github PK

Good afternoon @kwikius
I am interested in your project, and if you allow me, I would like to ask a few questions.
I have the opportunity to fly a real aircraft, but this is a very rare event and so I decided to try to get the data I need from the simulator.
As a hobby, I sometimes fly in MSFS2020, but as far as I know, this simulator is not suitable as a source of reliable data, and its hardware requirements are enormous.
On a real plane in flight, I receive data from gyroscopes (x, y, z - in angular velocities - dps or radians), and from accelerometers (x, y, z in 1G or 9.81 m/s/s)
The most important thing is that in real flight I can get up to 100-200 Hz to record data samples.
Because the code algorithm on the STM32 microcontroller that I am testing requires a high frequency of data updates from MEMS sensors in order for the Kalman filtering algorithms to work properly.
So I was puzzled by this question and found the flightgear simulator, but I did not find enough information to get the same frequency (about 100 Hz) data about gyroscopes and accelerometers from the simulator.
I read somewhere that the frequency of data through the UDP will be comparable to the FPS of the simulator, and that in the best case it will be about 30 Hz.
Although, in fact, I can get at least 30-50 Hz and that will already be a success!
Upon requests to obtain data from the simulator, I received answers from the search engine about

https://wiki.flightgear.org/Generic_protocol

I tried to output data to the serial port COM9, but I'm probably doing something wrong.
I work in Windows 10, but I also have Ubuntu 22.04 on a virtual machine.

My algorithm is the following.

1. In the folder C:\Program Files\FlightGear 2020.3\data\Protocol there are *xml files, I am trying to display the data specified in this file insgns-imu.xml
2. I enter the cmd console into the folder

C:\Program Files\FlightGear 2020.3\bin>

and I enter the command

fgfs --generic=serial,out,10,COM9,9600,insgns-imu

The flightgear simulator starts, but in the console it writes about the impossibility of opening the specified port and some strange characters.

C:\Program Files\FlightGear 2020.3\bin>Now checking for plug-in osgPlugins-3.6.5/osgdb_nvtt.dll
    1.19 [WARN]:general    Enabling ATI/AMD viewport hack
    5.05 [ALRT]:io         Error opening serial device "COM9" ═х єфрхЄё  эрщЄш єърчрээ√щ Їрщы.

    5.05 [ALRT]:io         Error opening device: COM9
    5.05 [ALRT]:io         Error opening channel communication layer.
    5.05 [ALRT]:io         I/O Channel config failed.

   22.68 [INFO]:nasal      KMA20 audio panel initialized
   22.70 [INFO]:nasal      Hobbs system stopped
   22.70 [INFO]:nasal      Hobbs system stopped
   22.70 [INFO]:nasal      Starter off
   22.71 [INFO]:nasal      KI266 dme indicator #0 initialized
   22.80 [INFO]:nasal      Electrical system initialized
   28.23 [INFO]:nasal      Astro Tech LC-2 Chronometer Loaded
   28.24 [ALRT]:flight     Failed to save initial FDM property state
   31.60 [INFO]:OSG
   31.60 [WARN]:OSG        PNG lib warning : iCCP: known incorrect sRGB profile
   31.64 [WARN]:OSG        PNG lib warning : iCCP: known incorrect sRGB profile
   32.76 [INFO]:nasal      Primer reset to 0
   33.63 [WARN]:OSG        PNG lib warning : iCCP: known incorrect sRGB profile
   33.69 [WARN]:OSG        PNG lib warning : iCCP: known incorrect sRGB profile
   33.70 [WARN]:OSG        PNG lib warning : iCCP: known incorrect sRGB profile
   33.70 [WARN]:OSG        PNG lib warning : iCCP: known incorrect sRGB profile
   33.71 [WARN]:OSG        PNG lib warning : iCCP: known incorrect sRGB profile
   33.74 [WARN]:OSG        PNG lib warning : iCCP: known incorrect sRGB profile
   33.74 [WARN]:OSG        PNG lib warning : iCCP: known incorrect sRGB profile
   33.75 [WARN]:OSG        PNG lib warning : iCCP: known incorrect sRGB profile
   33.75 [WARN]:OSG        PNG lib warning : iCCP: known incorrect sRGB profile
   33.76 [WARN]:OSG        PNG lib warning : iCCP: known incorrect sRGB profile
   33.77 [WARN]:OSG        PNG lib warning : iCCP: known incorrect sRGB profile
   33.78 [WARN]:OSG        PNG lib warning : iCCP: known incorrect sRGB profile
   33.78 [WARN]:OSG        PNG lib warning : iCCP: known incorrect sRGB profile
   33.78 [WARN]:OSG        PNG lib warning : iCCP: known incorrect sRGB profile
   33.79 [WARN]:OSG        PNG lib warning : iCCP: known incorrect sRGB profile
   35.00 [INFO]:nasal      Garmin 196 loading cities
   35.88 [INFO]:nasal      Garmin 196 loading cities done

After I couldn’t run simple generic protocol examples, I started looking at what parameters could be obtained from the flightgear simulator.
I found the fdm module, as I understand it, this is a flight data model based on the JSBSim model?

I looked at what parameters there were, but did not clearly find the values of angular velocities from the gyroscopes (perhaps they are called differently there, some kind of angular rate, or something like that).
It became clear to me that receiving data by generic protocol or even through UDP would not give me the required data update frequency.
I began to search for information further and found that it is possible to receive data via the telnet protocol - that’s actually how I found your project.
As far as I understand, you have tried to obtain data from the simulator in order to use it for your purposes, as if this data was obtained in a real flight on an airplane or close to it?
I'm still very confused in terms and technologies.
There is also some kind of Nasal, which, as I understand it, also allows you to receive data from the simulator.
In general, is it possible to obtain data from a flightgear, just as they do from MEMS gyroscopes during a real airplane flight?
Could you help me understand your project with a simple example?
It’s enough for me to figure out how to get one parameter, for example, acceleration along any of the axes.
I looked at what parameters are contained in internal properties, the /orientation section is the calculated angles in the simulator, and I need initial data from gyroscopes and accelerometers, according to their data, my code in the microcontroller will calculate the values of euler angles or quaternions.
On a real aircraft, I will receive this data from MEMS sensors, like the MPU-9250 or BMI-160 or flight speed from the airspeed sensor or NED value according to GPS data.
In general, do you think flightgear is suitable for replacing a real flight, for testing code, or should you choose another simulator, for example x-plane?
I hope you are still dealing with such issues and can help me and clarify some things.