On Saturday 10 October 2009 22:33:01 Curtis Olson wrote: > > Really, this is all in how the autopilot is tuned and configured. > > FlightGear doesn't model realistic control surface deflection rates so it's > possible to command an instantaneous deflection of the control surfaces.
Control surface deflection rate can be limited by inserting a low-pass filter between the output of the final PID-controller and the control surface. THis is done in the autopilot config file. > FlightGear also doesn't model how much load the airframe can endure before > pieces began to depart and go their own separate ways. > > Thus assuming infinite control surface deflection rates and perfectly rigid > and robust airframe, and assuming the flight dynamics are configured > correctly, what you see is a realistic response. > > You can tune the control surface movement rates and maximum deflection > angles in the autopilot configuration for each aircraft. This would be an > excellent place to start. > > This isn't a systemic FlightGear problem, it's an autopilot configuration > problem that seems to be replicated across many aircraft. > > But tuning autopilots is hard for most people, and probably for most > aircraft authors so this is an area that is not attended to very well. You > might be imagining that FlightGear has a single universal autopilot that > runs all airplanes the same way, and you'd be wrong. There is an > individual config file that sets up the cascading stages and inputs and > reference values and outputs for each stage. You can do a lot of neat > stuff with it, but if it's not well tuned you'll get a lot of unstable > behavior. > > For what it's worth I recently saw a very expensive UAV flying with a > poorly tuned autopilot and the result was not smooth and graceful whereas > the aircraft flew beautifully under manual control. > > Best regards, > > Curt. -- Roy Vegard Ovesen ------------------------------------------------------------------------------ Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
