Tony Peden said: > On Mon, 2004-04-05 at 16:04, Jim Wilson wrote: > > Jon S Berndt said: > > > > > On Mon, 5 Apr 2004 23:15:42 +0200 > > > Mathias Fröhlich <[EMAIL PROTECTED]> wrote: > > > > > > > >The onground property is now ok. > > > >You can reset now JSBSim aircraft. > > > >Thanks for the fix! > > > > > > > > > > ?? > > > > > > Was it "bad data"? > > > > > > > All that was bad was a flag caused the trim routine to be called or not called > > with a "tGround" parameter...whatever that is, which was discussed in this > > thread yesterday. Questions are still unanswered, so I'm sure that sometime > > down the road the trim routine will rear it's ugly head again. > > The trimming routine has several modes, one of which is tGround. That > tells it to iterate on altitude and pitch attitude until the gear forces > balance the weight. > > > tLongitudinal tells it to trim in-air with angle of attack for lift, > elevator for pitch, and thrust for speed. > > tFull tells it to trim all six axes, those above plus adjust the > controls, bank angle, and sideslip to trim yaw, roll, and side force. > > tTurn sets up the body axis rates to perform a tFull trim in a steady > state turn. > > If I knew of a way to make the trimming routine less sensitive to bad > data (such as a bad terrain altitude) or divine how it's supposed to set > itself up, I'd do it. > > I can think of things that could be done but they all involve either a > sacrifice in capability or attempting to make the trimming routine > smarter than it should be. > >
Thanks for the explanation. This does more than I originally thought. Would some sanity checks at the JSBSim.cxx level help? I'm not sure what they would be, other than the one mentioned before (that relates to this latest bug): "make sure we have wheels above the ground". To test that we'd need to know where the wheels were (e.g. z distance from the vrp). Best, Jim _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
