> Out of interest, did Mathias ever manage to fix the gear jitter at stationary > with his fancy integration scheme, and if so will it be going into FlightGear > when you merge up next? > > Cheers - Dave
No. (I hope this doesn't "open up a can of worms ...") Though it is acknowledged that Mathias' fix would have worked well, and is mathematically precise, the code overhead was sophisticated, large-ish, and somewhat complex - an evaluation that is, of course, open to interpretation and difference of opinion. The quandary I always face as development coordinator is in balancing design goals and actual capabilities. I had to consider the needs and perceived "comfort level" of the target audience[s], as well as myself. It led to a lot of really excruciatingly uncomfortable choices, some of which were so personally vexing that I continually put them off. At this point, yes, the gear still jitters, and it is still a high priority to be addressed. The route I prefer to take - at this time - is best described this way: The EOM and integration scheme now in use (which Mathias also adeptly refined) works quite well for almost anything that anyone wants to do with JSBSim. The single most important remaining problem that involves the dynamic math model is the same problem that the literature shows afflicts many other simulators: landing gear modeling at low and zero velocity. I do not feel it is the best solution at this time to consider a new and major change to the integration scheme in order to address this one problem. There are probably a few good approaches to fixing the gear problem - and it does need to be fixed. One good one is presented in an AIAA paper (AIAA-200?-4303). In that paper, the "tricycle approximation" is described. At some point, the integration scheme in JSBSim will probably be revisited, after some other approaches in JSBSim are modified. The gear jitter problem will be addressed. Right now there are other pressing needs. I don't know what else to say ... Jon _______________________________________________ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
