Re: [Flightgear-devel] autoflight
On Mon, 22 Mar 2004 16:51:00 -0600, David Culp <[EMAIL PROTECTED]> wrote in message <[EMAIL PROTECTED]>: > Would anyone be interested in an autoflight subsystem that acts as a > higher-level controller of the autopilot? If been thinking of making > one to avoid lots of nasal code which I've been using to almost, but > not quite, model a Boeing autoflight system. What is needed is a way > to keep track of the various autoflight modes and to automatically > switch from one to another. For instance, switching from level-change > to altitude-capture, and from approach mode to autoland mode, to name > two examples. ..another use for this, is for _formation_flight_training_, as in; setup a route, and a formation to fly. Such a system could also take input from, say, AI traffic, an instructor panel, networked FG traffic, or AI flak. ;-) ..allowing several _different_ types of planes in the formation, will help both training and planning real world formation flight, both for airshows and Oshkosh-arrivals-in-style, as these RL formations often are made up of various similar but different type planes, which may limit manouvering room for the larger formations, who would prefer to avoid a RL scenario causing statements like; "Hey, you guy's are running away from us outsiders!" "Oh, shut up, we're all stalling out over here!". ..it would also help debugging our fdm's, a TwinOtter oughtta move the same, both with JSBSim, yasim and uiuc, with the same ice etc on it. -- ..med vennlig hilsen = with Kind Regards from Arnt... ;-) ...with a number of polar bear hunters in his ancestry... Scenarios always come in sets of three: best case, worst case, and just in case. ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] autoflight
Vivian Meazza wrote: Erik Hofman wrote The way I want to see scripting end up is that the script controls the workflow, but most of this stuff is done using pain C++ code. ^^ That would make it both flexible and fast. Freudian slip? Hehe, that must be it. Erik ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
RE: [Flightgear-devel] autoflight
Erik Hofman wrote > > David Culp wrote: > > Would anyone be interested in an autoflight subsystem that acts as a > > higher-level controller of the autopilot? If been thinking > of making one to > > avoid lots of nasal code which I've been using to almost, > but not quite, > > model a Boeing autoflight system. What is needed is a way > to keep track of > > the various autoflight modes and to automatically switch > from one to another. > > For instance, switching from level-change to > altitude-capture, and from > > approach mode to autoland mode, to name two examples. > > > The way I want to see scripting end up is that the script > controls the > workflow, but most of this stuff is done using pain C++ code. ^^ > That would > make it both flexible and fast. > Freudian slip? Regards Vivian Meazza ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] autoflight
David Culp wrote: Would anyone be interested in an autoflight subsystem that acts as a higher-level controller of the autopilot? If been thinking of making one to avoid lots of nasal code which I've been using to almost, but not quite, model a Boeing autoflight system. What is needed is a way to keep track of the various autoflight modes and to automatically switch from one to another. For instance, switching from level-change to altitude-capture, and from approach mode to autoland mode, to name two examples. The way I want to see scripting end up is that the script controls the workflow, but most of this stuff is done using pain C++ code. That would make it both flexible and fast. Erik ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] autoflight
On Tuesday 23 March 2004 02:40, Jim Wilson wrote: > David Culp said: > > > On the surface it sounds like Andy is right. But maybe I don't > > > understand the objective. > > > > > > Would this do things like implement auto land mode? How would that > > > work? > > > > Here's one example. When you engage "level-change" the autothrottles go > > into "n1-hold" mode to hold climb power or idle, depending on whether you > > are climbing or descending. The pitch mode is then set to > > "speed-hold-with-pitch". When you are within a certain distance from the > > target altitude, the pitch mode changes to "capture-altitude-with-pitch", > > and the autothrottle mode changes to "speed-hold" or "mach-hold" > > (depending on altitude). > > > > So there are several things to be kept track of here. The autoflight > > system needs to know whether it's within capture distance of an altitude > > so it can automatically switch the pitch and autothrottle modes. It also > > has to switch automatically between airspeed and mach at about FL260. > > Also, it needs to clamp the target pitch differently depending on whether > > you are climbing or descending. And it needs to handle the case where > > the autothrottle is off, since the autopilot and autothrottle are > > separate systems. > > > > Other things the autoflight system does is handle takeoff/go-around > > modes, calculate climb N1 as a function of altitude, transition between > > one roll mode, such as heading-select and another, like localizer mode. > > In this case the heading-select mode is engaged while the localizer mode > > is armed; when the localizer is captured then the active roll mode > > becomes localizer mode. > > > > And then there's autoland, which is an automatic switch from approach > > mode (a combined roll/pitch mode) to a pitch mode of > > radio-altitude-capture, and an autothrottle mode of n1-hold (target = > > idle). > > > > If all this, and more, can be done with nasal then that's great. > > Ah ok, this is what I was hoping you were talking about :-) A lot of this > sounds familiar from things I've read online, but it's very difficult for > someone who's never been in a boeing cockpit to grasp the details. Yeah > I'd tend to say it would be a bad idea to do something this complex in > nasal, even if it could be done. It is a lot more than a few short scripts > worth. > > Would it be possible to do a "semi-generic" Boeing autoflight system that > could be configured for various models using xml? I'm not sure what these > parameters would be, but it seems like there must be variation between > models. > > Best, > > Jim Oh yes - there's considerable variation, not just between different a/c but between different weights. I've been spending quite a bit of time trying to auto-land the AN-225 but with landing weights between 1,200,000 and 600,000lbs I'm not really anywhere near solving it yet. LeeE ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] autoflight
> Would it be possible to do a "semi-generic" Boeing autoflight system that > could be configured for various models using xml? I'm not sure what these > parameters would be, but it seems like there must be variation between > models. Good idea. Here are some things that might differ: 1. Yaw axis (737 doesn't have it, 757 does, airbus does) 2. Radio altitude at touchdown (don't want to use 737 numbers in a 747!) 3. Go-around speed 4. VNAV and LNAV 5. Back-course tracking? 6. Selectable bank limiter 7. Control wheel steering mode 8. Number of Inertial reference units 9. Autoflight behaviour when approaching/exceeding limits Another thing the autoflight system can do is supply flight-director-pitch and flight-director-bank properties for use by a flight director display. I'll work on a subsystem. It may be Boeing-ish at first, but hopefully someone who knows Airbus or other systems can add some info. Dave -- David Culp davidculp2[at]comcast.net ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] autoflight
On Tuesday 23 March 2004 00:09, Jim Wilson wrote: > David Culp said: > > > > Would anyone be interested in an autoflight subsystem that acts as a > > > > higher-level controller of the autopilot? If been thinking of > > > > making one to avoid lots of nasal code [...] > > > > Andy Ross said: > > > Is this exactly the kind of high level glue task that a scripting > > > language is good for? Honestly, my thinking would be exactly the > > > opposite: replace the C++ stuff with Nasal/properties where possible. > > > > Nothing personal -:) > > One problem is I know C++, and I barely know nasal. I don't even know if > > what I want to do is possible with nasal. I can only spend so many days > > playing with it, so C++ would be most efficient for me. > > On the surface it sounds like Andy is right. But maybe I don't understand > the objective. > > Would this do things like implement auto land mode? How would that work? > > Best, > > Jim I've got a reasonable auto-land function for the YF-23 using Nasal, but it's very hacky. The same approach isn't working well for the AN-225 though. I'm not sure as to what extent this is highlighting deficiencies in the fdms. LeeE ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] autoflight
David Culp said: > > On the surface it sounds like Andy is right. But maybe I don't understand > > the objective. > > > > Would this do things like implement auto land mode? How would that work? > > > Here's one example. When you engage "level-change" the autothrottles go into > "n1-hold" mode to hold climb power or idle, depending on whether you are > climbing or descending. The pitch mode is then set to > "speed-hold-with-pitch". When you are within a certain distance from the > target altitude, the pitch mode changes to "capture-altitude-with-pitch", and > the autothrottle mode changes to "speed-hold" or "mach-hold" (depending on > altitude). > > So there are several things to be kept track of here. The autoflight system > needs to know whether it's within capture distance of an altitude so it can > automatically switch the pitch and autothrottle modes. It also has to switch > automatically between airspeed and mach at about FL260. Also, it needs to > clamp the target pitch differently depending on whether you are climbing or > descending. And it needs to handle the case where the autothrottle is off, > since the autopilot and autothrottle are separate systems. > > Other things the autoflight system does is handle takeoff/go-around modes, > calculate climb N1 as a function of altitude, transition between one roll > mode, such as heading-select and another, like localizer mode. In this case > the heading-select mode is engaged while the localizer mode is armed; when > the localizer is captured then the active roll mode becomes localizer mode. > > And then there's autoland, which is an automatic switch from approach mode (a > combined roll/pitch mode) to a pitch mode of radio-altitude-capture, and an > autothrottle mode of n1-hold (target = idle). > > If all this, and more, can be done with nasal then that's great. > Ah ok, this is what I was hoping you were talking about :-) A lot of this sounds familiar from things I've read online, but it's very difficult for someone who's never been in a boeing cockpit to grasp the details. Yeah I'd tend to say it would be a bad idea to do something this complex in nasal, even if it could be done. It is a lot more than a few short scripts worth. Would it be possible to do a "semi-generic" Boeing autoflight system that could be configured for various models using xml? I'm not sure what these parameters would be, but it seems like there must be variation between models. Best, Jim ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] autoflight
> On the surface it sounds like Andy is right. But maybe I don't understand > the objective. > > Would this do things like implement auto land mode? How would that work? Here's one example. When you engage "level-change" the autothrottles go into "n1-hold" mode to hold climb power or idle, depending on whether you are climbing or descending. The pitch mode is then set to "speed-hold-with-pitch". When you are within a certain distance from the target altitude, the pitch mode changes to "capture-altitude-with-pitch", and the autothrottle mode changes to "speed-hold" or "mach-hold" (depending on altitude). So there are several things to be kept track of here. The autoflight system needs to know whether it's within capture distance of an altitude so it can automatically switch the pitch and autothrottle modes. It also has to switch automatically between airspeed and mach at about FL260. Also, it needs to clamp the target pitch differently depending on whether you are climbing or descending. And it needs to handle the case where the autothrottle is off, since the autopilot and autothrottle are separate systems. Other things the autoflight system does is handle takeoff/go-around modes, calculate climb N1 as a function of altitude, transition between one roll mode, such as heading-select and another, like localizer mode. In this case the heading-select mode is engaged while the localizer mode is armed; when the localizer is captured then the active roll mode becomes localizer mode. And then there's autoland, which is an automatic switch from approach mode (a combined roll/pitch mode) to a pitch mode of radio-altitude-capture, and an autothrottle mode of n1-hold (target = idle). If all this, and more, can be done with nasal then that's great. Dave -- David Culp davidculp2[at]comcast.net ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] autoflight
David Culp said: > > > Would anyone be interested in an autoflight subsystem that acts as a > > > higher-level controller of the autopilot? If been thinking of > > > making one to avoid lots of nasal code [...] > > > Andy Ross said: > > > Is this exactly the kind of high level glue task that a scripting > > language is good for? Honestly, my thinking would be exactly the > > opposite: replace the C++ stuff with Nasal/properties where possible. > > Nothing personal -:) > One problem is I know C++, and I barely know nasal. I don't even know if what > I want to do is possible with nasal. I can only spend so many days playing > with it, so C++ would be most efficient for me. > On the surface it sounds like Andy is right. But maybe I don't understand the objective. Would this do things like implement auto land mode? How would that work? Best, Jim ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] autoflight
> > Would anyone be interested in an autoflight subsystem that acts as a > > higher-level controller of the autopilot? If been thinking of > > making one to avoid lots of nasal code [...] > > Is this exactly the kind of high level glue task that a scripting > language is good for? Honestly, my thinking would be exactly the > opposite: replace the C++ stuff with Nasal/properties where possible. Nothing personal -:) One problem is I know C++, and I barely know nasal. I don't even know if what I want to do is possible with nasal. I can only spend so many days playing with it, so C++ would be most efficient for me. Dave -- David Culp davidculp2[at]comcast.net ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] autoflight
David Culp wrote: > Would anyone be interested in an autoflight subsystem that acts as a > higher-level controller of the autopilot? If been thinking of > making one to avoid lots of nasal code [...] Is this exactly the kind of high level glue task that a scripting language is good for? Honestly, my thinking would be exactly the opposite: replace the C++ stuff with Nasal/properties where possible. Andy ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
