Autopilot PID controller tuning resources: Difference between revisions

Then you will get 6 new values displayed on the console at each FG loop. You will need to catch them and format the values in one line. Here is an example of a parser script written in Perl:

#!/usr/bin/perl -w

# prints: "input reference P I D output"

         }

}

Then you can write them in a file...

alexis@linear:~/fgfs$ /usr/local/bin/fgfs 2>&1 | ./PIDcontroller_parser.pl > my_file

If you use Linux, You can run Kst simultaneously to read the datas on the fly and watch them displayed together in real time while testing the aircraft.

Under Windows the script of the Linux chapter works (with some minor modifications) together with Live-Graph under Windows, too. Although the output to a logfile is not as fluently as you may experience it under Linux. To get an output you first need a slightly modified version of the above mentioned Perl script:

if (<STDIN>) {

print STDOUT "##|##\n";

}

}

The first 4 lines prepare a kind of "header" in the Logfile so that the Grapher can use it. In the while-part I added the pipe sign as separator so that Live-Graph can use the output. Copy and paste these lines into your favorite ASCII text editor and save it to your FG directory (e.g. save as "fgfsparser.pl"). Next you need to install a Perl Interpreter (e.g. [http://www.activestate.com/activeperl Activestate's Active Perl]). Now start Flightgear the following way:

path-to-fgfs-binary\fgfs.exe | perl fgfsparser.pl &gt; my_file 2&1

Feel free to prepare %fg-root%\preferences.xml to your desired needs if you plan to start at another location (instead of KSFO) or with another plane (instead of Cessna 172p) or if you want to change other options. As an alternative use the command line options to modify the start-up to your desired needs.