Curt, that sounds scary and reminds me of one oddity I notices some time ago. That time only pid controller was affected, but I don't remember the details. I think it was the integral sum that was not reset to zero. The current implementation of the FGPIDController calculates differences to the last iteration which somehow got out of sync between reloads and screwed up the reference value. Without having looked into it deeply, this should be no factor anymore. If the xml-autopilot subsystemgroup is reinitialized, all contained autopilots are deleted with the destructor called and alll components are recreated from scratch. Please check, if you can still observe your described bug.
Greetings, Torsten > Hi Torsten, > > One thing I noticed recently (but this could have been in the code for a > while) is that if a <reference> is a hard coded <value> instead of a > <property> then if the autopilot definition is reloaded (something you > might do often when tuning the autopilot) the value nodes can get > mismapped to other nodes. I took a brief look at the code and noticed > there had been some parser changes, but didn't unwind deep enough to get > to the bottom of this. > > As a practical explanation of what I'm seeing: let's assume the first stage > of the heading controller is to drive the heading-bug-error property to > zero. The reference in this case is always going to be zero since the > error term is computed inside the C/C++ code. In the same autopilot xml > file the altitude controller has a reference of "target-altitude" which is > a property. Let's say that is set to 3500 and I'm flying nicely. After > reloading the autopilot, these can get mixed up and all of the sudden the > heading controller is trying to drive the heading-bug-error to 3500 (the > altitude) and this of course can never happen so the aircraft enters a > perpetual circling pattern. > > The problem seems to be pretty deep in the parser which seems to have been > rewritten a bit with some new subobjects, but I wasn't able to unravel the > problem in the time I had available to look into it. :-( > > Thanks, > > Curt. > > On Fri, Nov 27, 2009 at 9:24 AM, Torsten Dreyer <tors...@t3r.de> wrote: > > Hi, > > > > I have just commited some changes to the xml autopilot. Along with a tiny > > bugfix comes a new feature which now allows more than one <autopilot> > > definition in the aircraft's -set.xml. > > You may now do something like this: > > <sim> > > <systems> > > <autopilot> > > <path>Aircraft/Hansajet/Systems/Hansajet-flightdirector.xml</path> > > </autopilot> > > <autopilot> > > <path>Aircraft/Hansajet/Systems/Hansajet-autopilot.xml</path> > > </autopilot> > > <autopilot> > > <path>Aircraft/Hansajet/Systems/Hansajet-digitalfilters.xml</path> > > </autopilot> > > </systems> > > </sim> > > > > Each <autopilot> element creates a new instance of the well known > > FGXMLAutopilot class which is added to a newly created SGSubsystemGroup. > > This > > subsystem group is added to the subsytem manager instead of the previous > > single instance of the autopilot. > > > > The idea behind this change is to be able to keep sophisticated autopilot > > configurations maintainable. > > > > No functional changes should happen to existing autopilots. > > > > Torsten > > > > > > > > ------------------------------------------------------------------------- > >----- Let Crystal Reports handle the reporting - Free Crystal Reports 2008 > > 30-Day trial. Simplify your report design, integration and deployment - > > and focus on > > what you do best, core application coding. Discover what's new with > > Crystal Reports now. http://p.sf.net/sfu/bobj-july > > _______________________________________________ > > Flightgear-devel mailing list > > Flightgear-devel@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/flightgear-devel > ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
