Jon Berndt <[EMAIL PROTECTED]> said: > > Basically what I had in mind was an adjustment of the target heading > based on > > the resulting devation values. I don't have the actual formula written > down, > > but it would involve doubling the devations and subtracting them from > the > > target heading and including an integral accumulated error adjustment > similar > > to the PI method that Curt used for altitude/gs. > > IIRC, the F-16 uses P+I for pitch (altitude/attitude hold) but that's for > both AP and non-AP flight - the pitch AP command merely enters the pitch > channel summed with the pitch trim command. Pitch hold will actually be an active mode in the AP code. It will be usable in a flight director mode, and I suppose it is possible that you could have a configuration that used a combination of thrust and trim commands to maintain a pitch on a glide slope. The thrust would be on a seperate controller anyway. How these would interact is probably more likely just a thrust setting that is calculated manually or by flight computer based on weight and other conditions entered into the equation. The trim would adjust to the GS inputs and the correct pitch would more or less be maintained. One other possible input might be something similar to the AoA sensor that the A-4 uses, but I'm not sure if they are reliable enough for an autothrottle. I'm no expert, but have been studying, so please add corrections and suggestions.
> Roll (heading, attitude hold, > etc.) seems to be purely proportional with rate limiting and a > spaghetti-like control surface mixing. The problem I see with any > autopilot is that it's going to need tweaking to avoid being all over the > place - I don't see one AP design as being sufficient for the variety of > aircraft we have or will have. You are talking about something that is > highly configurable aren't you? Yes I've been laying this out (until the other day when I decided to swap computers). You can get a rough idea by looking at /sim/autopilot/config (the properties I added to get the non c172 aircraft working--more or less--with the existing code). I'm finding that some of those adjustments aren't really necessary, but there will be many more. Also there will be configuration for which capabilities are supported by a particular device/system. This is for the basic AP function set. When we get to the more sophisticated flight computer level it remains to be figured out whether individual FMC models should be independantly coded or if there is a way to make an abstracted configurable FMC class. At the very least we would have to include the ability to run timed test sequences and semi-complex approach and landing sequences. > Without code? FWIW I designed the JSBSim > FCS components to also be able to handle being assembled into an > autopilot. Is there something there I should be looking at? > The question I have is, how would the desired heading, or roll > attitude, or switch positions, be communicated to us, if we so desired it? > Sounds like property nodes to me :-) Best, Jim _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
