Re: [Flightgear-devel] Jsbsim trim
Hi, On Montag, 26. April 2004 00:13, Arnt Karlsen wrote: ..ok, time for another of my stupid questions: Mathias, does your new model code include tire creep? And tire sidewall flex? No. At the moment the gear model I use is mostly unchanged. One problem here is the stiffness of the tire model. This is not a special characteristic of our tire model, I would expect that *every* tire model which models what it is called like, is kind of stiff. Stiff in the sense of differential equations which is what we definitly have here. The effect of a stiff ODE (=ordinary differential equation) is that you see some overshooting in the state values. This is what you see when you arrest the brakes and watch the aircraft jiggling. This effect of numerical timestepping couples then back to the tire physics. The short time loss of enough weight on the wheel while the aircraft is jiggling, reduces the friction of the wheel for a short time. When outer forces are applied (wind, thrust) for example your c172 begins to twist. What we attack at the moment is this part of the problem. And this part is sufficient to eliminate the jitter in the gear model and to prevent the aircraft from twisting with brakes appiled. The other part is the tire model itself. What I have in mind here is this Pacejka model. This is a simple parameter fitting generated formula which is, according to the references I found, often used in professional (car) simulations. This model is also something velocity dependent and, like Andy already told, it is harder to produce zero velocity with such a model. Even what I described above slightly moves because of this characteristic, but the movement is extremly small (about 1e-5ft/s). I expect that this tire model contains some kind of sidewall flex. *BUT* I think this is only included in the sense that such effects might show up somewhere and the parameters fitted contain them in some way. Anyway I expect that this model is much closer to a real tire than what we have now. An extension to that model to make it also position dependent is something which makes the problem only stiffer and we are back at the beginning... What we do at the moment is the first part of the problem. This works as expected on my development branch. But it is a long way until this ends in an enduser distribution ... One thing at one time but time will come ... ..a wee virtual demo on tire side wall flex: Take a parked, say Cessna 172, out at the leading edge of the very wing tip, and push it straight aft, then release, and repeat. ..once you get your repeat pushes close to the system resonance frequency, you will find wee pushes generates quite a yaw oscillation, and that it will swing around a point somewhere near the nose wheel. System here, is, tire side wall flexibility (some people prefer doing calculus on its inverse, tire sidewall stiffness), against _parts_ of the wings + tail + nose etc masses. What you describe here will most likely not happen with someting only velocity dependent. Keep it in your head and try to move your aircraft around its nose with that method when we have a better tire model. It you don't get it turned, we can look if this is doable :-) ..a wee virtual demo on tire creep: park an automobile sideways on a slope, so it leans with one side down, buth with the front (and rear) horizontal. Mark the position of at least the up side tires. Lock the steering wheel, say by turning off the ignition and taking the key out of the lock. Now get your fat ass outta the car and push it. ;-) :) ..15 feet forward, then back to those marks, will do fine. Note how far down the tires crept. Tire creep. ;-) This is what I expect to show up with the Pacejka model. Let's see when this is done ... Greetings Mathias -- Mathias Fröhlich, email: [EMAIL PROTECTED] ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Jsbsim trim
On Mon, 26 Apr 2004 09:54:43 +0200, Mathias wrote in message [EMAIL PROTECTED]: On Montag, 26. April 2004 00:13, Arnt Karlsen wrote: ..snip. ..a wee virtual demo on tire side wall flex: Take a parked, say Cessna 172, out at the leading edge of the very wing tip, and push it straight aft, then release, and repeat. ..once you get your repeat pushes close to the system resonance frequency, you will find wee pushes generates quite a yaw oscillation, and that it will swing around a point somewhere near the nose wheel. System here, is, tire side wall flexibility (some people prefer doing calculus on its inverse, tire sidewall stiffness), against _parts_ of the wings + tail + nose etc masses. What you describe here will most likely not happen with someting only velocity dependent. ..no? ;-) No velocity, plane is parked. Wee pushes, to exite the resonance. IME, the wee pushes straight aft gets the the plane dancing quite a bit, try it. ;-) Keep it in your head and try to move your aircraft around its nose ..not around the nose, around the nose wheel, usually around a point somewhere between the nose wheel and the mains. with that method when we have a better tire model. It you don't get it turned, we can look if this is doable :-) ..it even works on wet ice in RL. Also for turning the plane around. ;-) ..snip ..15 feet forward, then back to those marks, will do fine. Note how far down the tires crept. Tire creep. ;-) This is what I expect to show up with the Pacejka model. Let's see when this is done ... .. :-) -- ..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] Jsbsim trim
On Montag, 26. April 2004 11:49, Arnt Karlsen wrote: What you describe here will most likely not happen with someting only velocity dependent. ..no? ;-) No velocity, plane is parked. Wee pushes, to exite the resonance. IME, the wee pushes straight aft gets the the plane dancing quite a bit, try it. ;-) Sorry, I do not have an aircraft ... :( But I can well imagine. Keep it in your head and try to move your aircraft around its nose ..not around the nose, around the nose wheel, usually around a point somewhere between the nose wheel and the mains. Sorry, this is what I meant. By doing what you explained the vehicle will twist around its longitudinal axis. This will mostly not change the weight force on the nose wheel. So this one will stay fixed. What changes is the weight force on the other two wheels which will loose static friction for a short time. And when you apply a little side force during this time the aircraft will move. The nose wheel is fixed by static friction, thus the ac moves around the nosewheel ... The more I think about that, the more I can imagine that even that is in the Pacejka formula. Not with the real physical reason, but I can well imagine that it will just behave like that ... I am not shure how big the influence of the gear strut dynamics is in this case... Let's see ... I have to push this stuff I have now to Jon first ... Greetings Mathias -- Mathias Fröhlich, email: [EMAIL PROTECTED] ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Re: OpenAL runtime error
Melchior FRANZ wrote: * Roy Vegard Ovesen -- Sunday 25 April 2004 11:44: Initializing OpenAL sound manager fgfs: pcm.c:1050: snd_pcm_writei: Assertion `pcm-setup' failed. I'm using openal version 20030811-83 and openal-devel version 20030811-83 as der standard for SuSE 9.0 Got the same here with Linux 2.6.5 and the OpenAL from SuSE 9.0. Then I replaced OpenAL with cvs/head and compiled again. Now it works. The binary is running fine on SuSE-9.0 with Linux-2.6.5 - as long as you '--disable-sound' (I don't need it because they remove the speakers from my workplace-peecee :-)) Martin. -- Unix _IS_ user friendly - it's just selective about who its friends are ! -- ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] For glider modelers
On Fri 23. April 2004 23:49, you wrote: Martin, So far all I have is a good quality 3-view scanned from schweizer book in the museum library: http://www.spiderbark.com/fgfs/sgs-1-26_3-view.tiff Note that is 4.9mb and will only be available for a few days at that address. The only round tail in the museum's collection is hanging in the food court of a local shopping mall, so the detail and angles available might be limited. There's a later model 1-26 on display that I could easily access, so if there's anything there (e.g. cockpit) that you can use I'll snap a few shots. Best, Jim Thanks, it is fine detailed 3-view. I had used some hand drawed from internet. What i don't udestand is how is undercariage done on this sailplane and I will invite any photo of it. I have some nice cockpit snaps, but I am missing some snaps of intruments where you can read all markings. I am also missing some snap of extended airbrake,nose and tail from bottom. Thanks, Madr ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
[Flightgear-devel] Joystick problems...
Hi, Tanks for the explanation about YASim output data. Now I've another question. Due to the fact that I've the ThrustMaster Top Gun (...), for which a config file was added in the last release, I've tried to use it in FlightGear but it doesn't works. Truly it works, but seems that isn't recognized so the config file doesn't works right. What's the problem? I'd like to change the config file but it's impossible if the joystick is recognized like a two axis, two buttons joystick. However, Js-demo finds the ThrustMaster if it's connected. Why? Hi, Luca ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
[Flightgear-devel] FlightGear news letter?
Jon Berndt puts together a really nice quarterly news letter for the JSBSim project. Here is the first edition: http://www.jsbsim.org/JSBSimNewsletter_1_1.pdf There is a *lot* of things going on with the FlightGear project at various levels and it would be nice to have a monthly or quarterly summary in newsletter form for ourselves too. Along with interesting news and developments, this could be a great venue for posting various tutorials (scenery building, aircraft building, networking/interfacing, multiple displays, etc.) reports from people using FG for interesting applications, interviews with developers, reports from conferences or expos we attend, and maybe a few of my own insane rantings on wide ranging topics loosely related to computers or simulators. However, to make something like this work, we would need a creative and dedicated volunteer who would be willing to take this project on and be willing to put in the effort to push out each issue on time. Duties would involve assembling the information in a nice form (perhaps a pdf newsletter format, or perhaps a nice html online newsletter?) This person would need to go out and drum up participants and contributing authors, and probably pester them once in a while to finish their submissions on time. This person would probably need to jump in and write an article or two themselves to pad space. If anyone is interested in helping out the FG project in such a way, please let me know. We average over 4000 visits to the FG web site daily so this could be a great outlet for someone's creative abilities. Thanks, Curt. -- Curtis Olsonhttp://www.flightgear.org/~curt HumanFIRST Program http://www.humanfirst.umn.edu/ FlightGear Project http://www.flightgear.org Unique text:2f585eeea02e2c79d7b1d8c4963bae2d ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Joystick problems...
On Montag, 26. April 2004 18:33, Luca Masera wrote: Now I've another question. Due to the fact that I've the ThrustMaster Top Gun (...), for which a config file was added in the last release, I've tried to use it in FlightGear but it doesn't works. Truly it works, but seems that isn't recognized so the config file doesn't works right. What's the problem? I'd like to change the config file but it's impossible if the joystick is recognized like a two axis, two buttons joystick. However, Js-demo finds the ThrustMaster if it's connected. Why? I believe that the name in quotes must *exactly* (case sensitive?) match the name in the config file. Here js_test printout for my joystick: Joystick test program. ~~ Joystick 0: THRUSTMASTER Top Gun Afterburner ... How does js_test call your joystick? Greetings Mathias -- Mathias Fröhlich, email: [EMAIL PROTECTED] ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
[Flightgear-devel] (no subject)
I changed the name in the config file with the one printed by js-demo but the joystick doesn't yet work.So I've checked out the property tree in FlightGear and I've found that the config file used is the one written for the default joystick, exactly the file joystick.xml, which number, in the property tree, is zero. So I've copied the config file for the ThrustMaster in the file joystic.xml and now it works right. Hi, Luca ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] (no subject)
On Montag, 26. April 2004 19:17, Luca Masera wrote: I changed the name in the config file with the one printed by js-demo but the joystick doesn't yet work.So I've checked out the property tree in FlightGear and I've found that the config file used is the one written for the default joystick, exactly the file joystick.xml, which number, in the property tree, is zero. So I've copied the config file for the ThrustMaster in the file joystic.xml and now it works right. The name tag really matches the name js_test prints but it is not taken? Strange ... Greetings Mathias -- Mathias Fröhlich, email: [EMAIL PROTECTED] ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] MD-11
Hi Innis, I just sent my MD11 files to Erik, so hopefully they show up in CVS one of these days. I haven't done any _systematic_ testing yet, so I can't confirm whether or not the 850 units value is the absolute cut-off or not, but moving both CoG and Main gear forward to less than 850 unit solved the initialization problem for me. :-) Now, does moving the CoG forward impact anything at all? I can imagine that it doesn't when we move everthing else forward too, by the same number of units, but I'm still unfamiliar enough to be completely wrong here. Moving just the CoG and the main gears didn't really seem to impact the feel of the flight model though. Just out of curiousity: Did you also use aeromatic to generate your MD-11 config file, or did you build it manually. I saw similar, but slightly different values in your config file, compared to the ones I got from aeromatic. Speaking of a 3D model, yeah, it would be cool to stitch in a FS98 model until we have a decent native GPL'ed model. I've never done this though, so some useful tips would be more than welcome. :-) Cheers, Durk On Sunday 25 April 2004 13:05, Innis Cunningham wrote: Hi Durk I don't know if you have actually got the A/C to sit on the ground correctly yet.But I have got both the 747 and MD11 to sit correctly by making sure the CG figure is no further back than 850 X units and the MLG figures also no further back than 850 X units any further back and the model does not sit correctly. See below for extracts from both my config files I don't know if you are interested but I grabed a MD11 from FS 98 from Simviation just so at least the model looked like a MD11. If you are not familiar with using FS98 models give me a yell. Durk Talsma writes On Saturday 24 April 2004 14:50, Erik Hofman wrote: Innis Cunningham wrote: Also the further back you put the CofG the higher off the ground the A/C seems to start. This almost sounds like and axis mismatch. Is the gear located in the structural frame or in the body frame? It actually reminds me that during one of my tweaks I noticed that I found the aircraft to flip-over sideways, while I was only moving either gears or CoG forward or backward. I didn't give it much thougth then, and therefore don't remember the exact parameters that made this happen. But, would it be possible than that specifically in the JSB trimming routine somehow. I feel it's still a bit premature, but if anybody wants to play with the MD11 files, I could offer them for cvs inclusion. Who should I send them to? Curt? Erik? Cheers, Durk Cheers Innis _ Personalise your phone with chart ringtones and polyphonics. Go to http://ringtones.com.au/ninemsn/control?page=/ninemsn/main.jsp ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] MD-11
On Sunday 25 April 2004 18:46, Ampere K. Hardraade wrote: Hi, If you guys want a MD-11 specifically for FlightGear, I think I may be able to make one. I have 3D Max Studio but I'm not sure whether FlightGear supports 3DS files. Regards, Ampere Oh yes! A nice MD-11 3D model would be absolutely welcome. Let me (us) know if you have any questions. Thanks, Durk ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
[Flightgear-devel] Impossible to run without sound?
After a few tries I managed to get the latest CVS working again (thanks for the helpFred!), I also found outsome other things. I learned that it is impossible to compile without sound support. If you remove the #define ENABLE_AUDIO_SUPPORT, compile errors will result. Is there a way to disable sound support (besides the runtime parameter)? I would like to know this, since I did not dive into the OpenAl stuff yet, and really dont use sound anyway.. Also can someone tell me how I can succesfully run FG from the MSVC debugger? how do you get it to find the DATAdirectory and command line parameters? I run it from a batch file now, but I noticed FG is picky about its location relative to the DATA directory. Greetings, Avi ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Impossible to run without sound?
After a few tries I managed to get the latest CVS working again (thanks for the help Fred!), I also found out some other things. I learned that it is impossible to compile without sound support. If you remove the #define ENABLE_AUDIO_SUPPORT, compile errors will result. Is there a way to disable sound support (besides the runtime parameter)? I would like to know this, since I did not dive into the OpenAl stuff yet, and really dont use sound anyway.. I don't thing it is possible. Setting up FG with OpenAL is not a big deal though. I posted the stuff involved 2 days ago. Also can someone tell me how I can succesfully run FG from the MSVC debugger? how do you get it to find the DATA directory and command line parameters? I run it from a batch file now, but I noticed FG is picky about its location relative to the DATA directory. Open the settings/properties of your FG project, and add the command line arguments in the 'Debugging' tab, in the 'Command Arguments' field. Use it also if you want to start FG without debugging, in the Release configuration. My arguments includes : --fg-root=i:/Flightgear/cvs/fgfsbase --geometry=1024x768 --aircraft=ufo --airport-id=KSFO and so on. -Fred ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Joystick problems...
On Monday 26 April 2004 19:05, Mathias Fröhlich wrote: On Montag, 26. April 2004 18:33, Luca Masera wrote: Now I've another question. Due to the fact that I've the ThrustMaster Top Gun (...), for which a config file was added in the last release, I've tried to use it in FlightGear but it doesn't works. Truly it works, but seems that isn't recognized so the config file doesn't works right. What's the problem? I'd like to change the config file but it's impossible if the joystick is recognized like a two axis, two buttons joystick. However, Js-demo finds the ThrustMaster if it's connected. Why? I believe that the name in quotes must *exactly* (case sensitive?) match the name in the config file. Here js_test printout for my joystick: Joystick test program. ~~ Joystick 0: THRUSTMASTER Top Gun Afterburner ... I had problems with my Thrustmaster Top Gun joystick on Windows. The name included the registered trademark (R) character. It showed up as [] in js_test. There was no way for Flightgear to recognize the name (because of the (R) character). My solution was to uninstall the Thrustmapper driver for my joystick, then the name became somthing else without the (R). -- Roy Vegard Ovesen ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
[Flightgear-devel] OpenAL breaks voice ATIS
Hi folks,
The recent OpenAL change has broken voice ATIS (start up the default Cessna at KSFO
and transfer the 118.85 standby freq on comm1 to be active - the program will
segfault) and I can't seem to figure out a fix on my own. The segfault occurs in
ATCVoice.cxx line 172, which is memcpy. This is copying sections from the original
voice data buffer to make up a new custom data buffer containing the message. My
first thought was that the rawSoundData buffer was getting deleted behind my back, so
I modified LoadVoice to copy the buffer obtained from openal (patch at end of mail -
don't apply this!). However, this now dies at the new memcpy line in LoadVoice. The
rawDataSize returned from the sound sample is correct according to a quick check with
a hex editor, so I can only conclude that the memory address returned by get_data()
from the sound sample is not that of the data, or that it's been deleted by the sample
before I call get_data()? Any thoughts on this - I'm somewhat out of ideas.
Cheers - Dave
===
RCS file: /var/cvs/FlightGear-0.9/source/src/ATC/ATCVoice.cxx,v
retrieving revision 1.7
diff -u -r1.7 ATCVoice.cxx
--- a/ATCVoice.cxx 24 Apr 2004 19:28:12 - 1.7
+++ b/ATCVoice.cxx 26 Apr 2004 21:27:12 -
@@ -38,6 +38,7 @@
FGATCVoice::~FGATCVoice() {
// delete SoundData;
+delete[] rawSoundData;
}
// Load the two voice files - one containing the raw sound data (.wav) and one
containing the word positions (.vce).
@@ -45,8 +46,10 @@
bool FGATCVoice::LoadVoice(string voice) {
// FIXME CLO: disabled to try to see if this is causign problemcs
// return false;
-
+
ifstream fin;
+
+ cout voice = voice endl;
SGPath path = globals-get_fg_root();
path.append( ATC );
@@ -55,7 +58,11 @@
SoundData = new SGSoundSample( path.c_str(), file.c_str() );
rawDataSize = SoundData-get_size();
- rawSoundData = SoundData-get_data();
+ cout rawDataSize = rawDataSize endl;
+ char* tmpptr = SoundData-get_data();
+ rawSoundData = new char[rawDataSize];
+ memcpy(rawSoundData, tmpptr, rawDataSize);
+ //rawSoundData = SoundData-get_data();
path = globals-get_fg_root();
string wordPath = ATC/ + voice + .vce;
___
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Re: [Flightgear-devel] OpenAL breaks voice ATIS
David Luff wrote: Hi folks, The recent OpenAL change has broken voice ATIS (start up the default Cessna at KSFO and transfer the 118.85 standby freq on comm1 to be active - the program will segfault) and I can't seem to figure out a fix on my own. The segfault occurs in ATCVoice.cxx line 172, which is memcpy. This is copying sections from the original voice data buffer to make up a new custom data buffer containing the message. My first thought was that the rawSoundData buffer was getting deleted behind my back, so I modified LoadVoice to copy the buffer obtained from openal (patch at end of mail - don't apply this!). However, this now dies at the new memcpy line in LoadVoice. The rawDataSize returned from the sound sample is correct according to a quick check with a hex editor, so I can only conclude that the memory address returned by get_data() from the sound sample is not that of the data, or that it's been deleted by the sample before I call get_data()? Any thoughts on this - I'm somewhat out of ideas. Ooops, you are right, I didn't test ATIS voice when I switched to OpenAL. Yes, the way openal works is you call a function to load the wav file, then you call a function that buffers it internally to openal, then you call a function that cleans up (which delete the in memory copy you have access to.) I updated the sound_sample api to allow you to request that this in memory version not be immediately cleaned up, but instead be deleted when the sound sample destructor is called. This is less efficient memory-wise, but gives you optional access to the raw data for those times when you want to manipulate it. Regards, Curt. -- Curtis Olsonhttp://www.flightgear.org/~curt HumanFIRST Program http://www.humanfirst.umn.edu/ FlightGear Project http://www.flightgear.org Unique text:2f585eeea02e2c79d7b1d8c4963bae2d ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
[Flightgear-devel] Impossible to run without sound?
From: Frederic Bouvier [EMAIL PROTECTED] From: Avi Levy [EMAIL PROTECTED] [...] Is there a way to disable sound support (besides the runtime parameter)? I would like to know this, since I did not dive into the OpenAl stuff yet, and really dont use sound anyway.. I don't thing it is possible. Setting up FG with OpenAL is not a big deal though. I posted the stuff involved 2 days ago. Sure, there's no _technical_ problem in installing OpenAL; providing you don't mind upgrading to experimental libraries (recent CVS, little testing) on a stable machine. FGFS is disappearing from all but one of my computers and, on the remaining one, it occupies a ChRoot for segregation. A configure-time switch that eliminates the build dependency would also be convenient because I normally run FGFS silent. (I'm not suggesting that the switch to OpenAL was a bad idea) ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
