Re: [Flightgear-devel] AI Carrier with Aircraft, and the last JSBSim version
On ven 29 août 2008, Bill Galbraith wrote: > > With Catapult it is less a problem, with answering time > > delay, i mean it should work. > > Catapults features need only to know the "starting position" > > with a more or less value precision: a carrier with 20 km > > speed does 5.6 meter per second => 0.50 1/10 sec => 0.05 1/100 sec > > > > The heading won't be a difficulty, the heading of the > > carrier is not quickly moving. > > I haven't done much with FG or JSBSim lately, but thought I'd add my $0.02 > worth, since I'm working on this stuff on a 'real' simulator. > > Not all carriers shoot off at the carrier's heading. Some US carriers > (sorry, I can't name names) are left of carrier heading, up to 8 degrees. > Some secondary cats (cats 3 and 4) are off even more. (I think they even > show some of that in Top Gun). Which is right, however, the catapult heading and start position could be given by a Nasal script, if the synchronisation delay is not too high, can we say that something in between 1/10 sec and 1/100 sec remains acceptable ? is realistic ? With the existing CVS JSBSim i have been able to test it, with Foch Zero speed, Dave Culp with his F-4N does it with the Nimitz (the values are within the FDM External_Reactions parameters) > > Plus, the force applied is in carrier axes (with the aforementioned > offset), not in aircraft body axes. The force must be translated into body > axis so that it tracks down the cat track. That way, if you are lined up > poorly on the cat, it straightens you out. > > The carrier is most likely not going to be changing heading or speed during > a launch, but it should be accounted for. With a high-seas condition, the > boat is rock, roll, and heave a lot. Traps are REALLY difficult when the > seas are rough. They probably have to time a shot off a cat to coincide > with an up motion, so that you don't get shot into a wave. YES, the best, would be, to have the right calculation during any high-seas conditions. With a lot of others problems , mainly about the aircraft itself. Will it be, with the existing simulator, able to stay at the right same place when parking? > > Bill > > > Anyhow, we could wonder why that kind of calculation is not out of FDM, that dynamic position calculation, which is necessary to any FDM, is the same. There is no specific good reason (but FG development progress historic ) to find it included into YASim. I should be a module. When collision detection ( which will require a dynamic position calculation) will be done , will it be specific to each FDM ? Regards -- Gérard http://pagesperso-orange.fr/GRTux/ "J'ai décidé d'être heureux parce que c'est bon pour la santé. Voltaire " - This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] AI Carrier with Aircraft, and the last JSBSim version
> With Catapult it is less a problem, with answering time > delay, i mean it should work. > Catapults features need only to know the "starting position" > with a more or less value precision: a carrier with 20 km > speed does 5.6 meter per second => 0.50 1/10 sec => 0.05 1/100 sec > > The heading won't be a difficulty, the heading of the > carrier is not quickly moving. > I haven't done much with FG or JSBSim lately, but thought I'd add my $0.02 worth, since I'm working on this stuff on a 'real' simulator. Not all carriers shoot off at the carrier's heading. Some US carriers (sorry, I can't name names) are left of carrier heading, up to 8 degrees. Some secondary cats (cats 3 and 4) are off even more. (I think they even show some of that in Top Gun). Plus, the force applied is in carrier axes (with the aforementioned offset), not in aircraft body axes. The force must be translated into body axis so that it tracks down the cat track. That way, if you are lined up poorly on the cat, it straightens you out. The carrier is most likely not going to be changing heading or speed during a launch, but it should be accounted for. With a high-seas condition, the boat is rock, roll, and heave a lot. Traps are REALLY difficult when the seas are rough. They probably have to time a shot off a cat to coincide with an up motion, so that you don't get shot into a wave. Bill - This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] AI Carrier with Aircraft, and the last JSBSim version
On mar 26 août 2008, Melchior FRANZ wrote: > * gerard robin -- 8/26/2008 11:23 AM: > > Won't it be possible to get with a generic Nasal script? > > > > with the closest Carrier: > > The Catapults position with heading. > > The wire positions Left/right position. > > Could be problematic. The involved subsystems are handled at different > places in the main loop, which can easily cause synchronization problems. > (aircraft -> FDM update, carrier position -> AI update, Nasal loops -> > event handler, visuals -> view manager update). As Czaba wrote, letting > the FDM do that (in connection with the fgfs interface code) is more > promising. > > SNIP > m. > Yes and No, You are right with the wires, if their is any time delay i won't work correctly., and the AC will stop out of the carrier area. With Catapult it is less a problem, with answering time delay, i mean it should work. Catapults features need only to know the "starting position" with a more or less value precision: a carrier with 20 km speed does 5.6 meter per second => 0.50 1/10 sec => 0.05 1/100 sec The heading won't be a difficulty, the heading of the carrier is not quickly moving. -- Gérard http://pagesperso-orange.fr/GRTux/ "J'ai décidé d'être heureux parce que c'est bon pour la santé. Voltaire " - This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] AI Carrier with Aircraft, and the last JSBSim version
On mar 26 août 2008, Csaba Halász wrote: > On Tue, Aug 26, 2008 at 11:23 AM, gerard robin <[EMAIL PROTECTED]> wrote: > > On mar 26 août 2008, gerard robin wrote: > >> On lun 25 août 2008, Jon S. Berndt wrote: > >> > As posted by Dave in the JSBSim mailing list, I firmly agree: > >> > determining carrier location and orientation should not be an FDM > >> > specific function. This needs to be more configurable from the > >> > FlightGear side, so any FDM can take that information and do with it > >> > what it needs to do cat/hook ops. > > I might be misunderstanding something here, but currently the generic > groundcache code returns catapults and wires: > > // Return the nearest catapult to the given point > // pt in wgs84 coordinates. > double get_cat(double t, const SGVec3d& pt, >SGVec3d end[2], SGVec3d vel[2]); > > // Return 1 if the hook intersects with a wire. > // That test is done by checking if the quad spanned by the points pt* > // intersects with the line representing the wire. > // If the wire is caught, the cache will trace this wires endpoints > until // the FDM calls release_wire(). > bool caught_wire(double t, const SGVec3d pt[4]); > > // Return the location and speed of the wire endpoints. > bool get_wire_ends(double t, SGVec3d end[2], SGVec3d vel[2]); > > // Tell the cache code that it does no longer need to care for > // the wire end position. > void release_wire(void); > > The FDM only has to use this information. I have done that for the > wires, but I don't understand the catapult model so couldn't do the > cats. Hello Csaba This will probably not answer directly your question. Anyhow , because most of my models were developed with older ( very old) FG version i do use that JSBSim patched version ( was done by Mathias Fröhlich) which include the Carrier features. It is perfectly working, catapults and wire using the FG Groundcache I have a lot of Naval AC which are still flying with it into some friends old computers (old, both, friends and computers :) ) Sure we can't get any comparison with JSBSim now, was the copper age :) I hope that, source, could give you explanations Here the JSBSIm source patched http://pagesperso-orange.fr/GRTux/JSBSim.tar.gz Cheers -- Gérard http://pagesperso-orange.fr/GRTux/ "J'ai décidé d'être heureux parce que c'est bon pour la santé. Voltaire " - This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] AI Carrier with Aircraft, and the last JSBSim version
* gerard robin -- 8/26/2008 11:23 AM: > Won't it be possible to get with a generic Nasal script? > > with the closest Carrier: > The Catapults position with heading. > The wire positions Left/right position. Could be problematic. The involved subsystems are handled at different places in the main loop, which can easily cause synchronization problems. (aircraft -> FDM update, carrier position -> AI update, Nasal loops -> event handler, visuals -> view manager update). As Czaba wrote, letting the FDM do that (in connection with the fgfs interface code) is more promising. > Like we have a generic aar.nas (though it is not usable for me, too generic ) > > we could have, a carrier.nas. I intend to merge Generic/aar.nas with Nasal/fuel.nas (which are almost the same already), and to offer a simple interface for special needs. The detection of a tanker (not necessarily a flying one) is a generic job, and so is refueling. The part that may differ is what happens with fuel that entered the aircraft. And for that we could just write the fuel amount to a property. An aircraft could then attach a listener to that which takes the fuel and does whatever it likes, and finally resets the property to zero. m. - This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] AI Carrier with Aircraft, and the last JSBSim version
On Tue, Aug 26, 2008 at 11:23 AM, gerard robin <[EMAIL PROTECTED]> wrote: > On mar 26 août 2008, gerard robin wrote: >> On lun 25 août 2008, Jon S. Berndt wrote: >> > As posted by Dave in the JSBSim mailing list, I firmly agree: determining >> > carrier location and orientation should not be an FDM specific function. >> > This needs to be more configurable from the FlightGear side, so any FDM >> > can take that information and do with it what it needs to do cat/hook >> > ops. I might be misunderstanding something here, but currently the generic groundcache code returns catapults and wires: // Return the nearest catapult to the given point // pt in wgs84 coordinates. double get_cat(double t, const SGVec3d& pt, SGVec3d end[2], SGVec3d vel[2]); // Return 1 if the hook intersects with a wire. // That test is done by checking if the quad spanned by the points pt* // intersects with the line representing the wire. // If the wire is caught, the cache will trace this wires endpoints until // the FDM calls release_wire(). bool caught_wire(double t, const SGVec3d pt[4]); // Return the location and speed of the wire endpoints. bool get_wire_ends(double t, SGVec3d end[2], SGVec3d vel[2]); // Tell the cache code that it does no longer need to care for // the wire end position. void release_wire(void); The FDM only has to use this information. I have done that for the wires, but I don't understand the catapult model so couldn't do the cats. -- Csaba/Jester - This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] AI Carrier with Aircraft, and the last JSBSim version
On mar 26 août 2008, gerard robin wrote: > On lun 25 août 2008, Jon S. Berndt wrote: > > > Hello, > > > > > >... > > > > > > In order to get these data into the JSB FDM, the crude solution could > > > be, to > > > include the yasim calculation part into JSBSim. > > > > > > I feel that won't be the more elegant solution, and i am not sure that > > > Jon > > > would agree on it. :) > > > > > > Though, i am not aware, about the FG source organisation, i dare that > > > question: > > > > > > Won't it be possible to calculate and to give on request ( when we are > > > close > > > to a Carrier ) these data. > > > I mean, the cats and wires positions ? > > > > > > Cheers > > > -- > > > Gérard > > > http://pagesperso-orange.fr/GRTux/ > > > > As posted by Dave in the JSBSim mailing list, I firmly agree: determining > > carrier location and orientation should not be an FDM specific function. > > This needs to be more configurable from the FlightGear side, so any FDM > > can take that information and do with it what it needs to do cat/hook > > ops. > > > > Jon > > YES, the problem won't be technical, but mainly "a policy" problem. > > Since that feature is included into YASim , I fear the answer (again, i > got it..), "for model which want carrier features, YASim answer the > request" :). > > I hope that the prize to do it, will not be too high. > > Cheers Sorry, I answer to myself, :) Though, more the prize is high, more the chances to obtain it, are large More seriously. Won't it be possible to get with a generic Nasal script? with the closest Carrier: The Catapults position with heading. The wire positions Left/right position. Like we have a generic aar.nas (though it is not usable for me, too generic ) we could have, a carrier.nas. I am not a Nasal expert, so can't do it. However, there is so many Nasal expert here ... :) Regards -- Gérard http://pagesperso-orange.fr/GRTux/ "J'ai décidé d'être heureux parce que c'est bon pour la santé. Voltaire " - This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] AI Carrier with Aircraft, and the last JSBSim version
On lun 25 août 2008, Jon S. Berndt wrote: > > Hello, > > > >... > > > > In order to get these data into the JSB FDM, the crude solution could > > be, to > > include the yasim calculation part into JSBSim. > > > > I feel that won't be the more elegant solution, and i am not sure that > > Jon > > would agree on it. :) > > > > Though, i am not aware, about the FG source organisation, i dare that > > question: > > > > Won't it be possible to calculate and to give on request ( when we are > > close > > to a Carrier ) these data. > > I mean, the cats and wires positions ? > > > > Cheers > > -- > > Gérard > > http://pagesperso-orange.fr/GRTux/ > > As posted by Dave in the JSBSim mailing list, I firmly agree: determining > carrier location and orientation should not be an FDM specific function. > This needs to be more configurable from the FlightGear side, so any FDM can > take that information and do with it what it needs to do cat/hook ops. > > Jon > > YES, the problem won't be technical, but mainly "a policy" problem. Since that feature is included into YASim , I fear the answer (again, i got it..), "for model which want carrier features, YASim answer the request" :). I hope that the prize to do it, will not be too high. Cheers -- Gérard http://pagesperso-orange.fr/GRTux/ "J'ai décidé d'être heureux parce que c'est bon pour la santé. Voltaire " - This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] AI Carrier with Aircraft, and the last JSBSim version
> Hello, > >... > > In order to get these data into the JSB FDM, the crude solution could > be, to > include the yasim calculation part into JSBSim. > > I feel that won't be the more elegant solution, and i am not sure that > Jon > would agree on it. :) > > Though, i am not aware, about the FG source organisation, i dare that > question: > > Won't it be possible to calculate and to give on request ( when we are > close > to a Carrier ) these data. > I mean, the cats and wires positions ? > > Cheers > -- > Gérard > http://pagesperso-orange.fr/GRTux/ As posted by Dave in the JSBSim mailing list, I firmly agree: determining carrier location and orientation should not be an FDM specific function. This needs to be more configurable from the FlightGear side, so any FDM can take that information and do with it what it needs to do cat/hook ops. Jon - This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
[Flightgear-devel] AI Carrier with Aircraft, and the last JSBSim version
Hello, There is, into the recent FDM JSBSim update, a new huge feature with is the "External_Forces", this gives us, a lot of new facilities for model development, like mooring rope, chutes, catapults, hook, mules and so on. Each external_force can be defined "BODY" or "LOCAL". Working on an Aircraft (Crusader) with Carrier (Foch) I am looking for the right solution to get the positions of the Carrier with its components catapults and wires. Into FG source, we can find some code which gives, regarding the AI, the positions., global x-y-z, and lat lon. I have found it for Carrier and Tankers (very useful for refuel), and probably there for any AI models. However there is nothing regarding the Carriers components, catapults and wires positions. Into YASim the positions of each component, catapults and wires positions are calculated. In order to get these data into the JSB FDM, the crude solution could be, to include the yasim calculation part into JSBSim. I feel that won't be the more elegant solution, and i am not sure that Jon would agree on it. :) Though, i am not aware, about the FG source organisation, i dare that question: Won't it be possible to calculate and to give on request ( when we are close to a Carrier ) these data. I mean, the cats and wires positions ? I guess, if we had these values it should possible to process them into JSBsim in order to get an achieved Carrier Landing/takeOFF simulation. At least , easier for Jon to include that simulation into JSBSim. I can be wrong, it could be many other better approach Cheers -- Gérard http://pagesperso-orange.fr/GRTux/ "J'ai décidé d'être heureux parce que c'est bon pour la santé. Voltaire " - This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
