Re: [Flightgear-devel] ATC services for FSWeekend...
On Sat, 7 Nov 2009 04:55:54 -0800 (PST), Jr. wrote in message <128049.27129...@web46402.mail.sp1.yahoo.com>: > Hello all -- sorry about my abrupt exit this morning -- especially to > you, Jomo, whom I feel I left holding the reins. To be honest, the > level of chaos was just too much for me. I'm happy to volunteer ATC > services for events where the participants are all attempting to work > within the system, but when it becomes a free-for-all I just don't > feel like I can manage. I apologize to anyone whom I may have let > down and hope that the rest of the event goes well. I will probably > participate as a pilot at some point. Sorry again, and thanks. > Sincerely, -R. (MD-Terp) > > Robert M. Shearman, Jr. > Transit Operations Supervisor, > University of Maryland Department of Transportation > also known as rm...@umd.edu ..sounds like ATC needs to be able to use AAA to bring down EA in a boring way to EAP's and in an eminently satisfying way to ATC. ;o) -- ..med vennlig hilsen = with Kind Regards from Arnt... ;o) ...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. -- Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] autopilot vs joystick
Curt, Yes, there's a way to implement *anything* using the JSBSim control system components (that's by design). What is the spec for autobrakes? In any case, JSBSim needs the ability to read the raw control inputs directly, if it is desired to process those within JSBSim itself (again, that's an intentional design feature). JSBSim has had the ability to model FBW control systems for years (see the F-16 model). As well, there are a growing number of GNC system models being written for JSBSim aircraft - though most have not been hooked up to be used from within FlightGear. That's great that such a feature could be added to flightgear itself for use by other FDMs, but the ability to read the raw control inputs needs to be maintained. Jon Hi James, I think your analysis is pretty much dead on. We are missing a layer of abstraction. Ideally, the raw control inputs would be fed into a separate branch of the property tree, and then the actual control surface positions would be sent to the FDM. This would allow us to create fly by wire systems that translate inputs to outputs in arbitrary ways. For simple aircraft with direct mechanical controls (or for aircraft where all the flight controls and control surface modeling is handled at the FDM layer), we could have a simple FBW module that just does a 1-to-1 copy of the values. In the case of JSBSim aircraft, perhaps there's a way to implement autobrakes entirely within JSBsim and work around the problem in this particular case? Regards, Curt. -- Curtis Olson: http://baron.flightgear.org/~curt/ -- Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Call for Help (SoundSystem listener orientation)
I wrote: >> I'm gradually figuring out a little bit of what the viewer >> code is doing. >> >> In particular: As for the basic "cockpit lookfrom" view, >> the viewer.cxx "reference frame" for attitudes is as follows: >> >> Suppose you are over the Gulf of Guinea, at (lat,lon) = (0,0). >> Then the reference frame orientation can be achieved via: >> -- The aircraft X-axis (nose) headed south. >> -- The aircraft Y-axis (starboard wingtip) pointing up. >> -- The aircraft Z-axis (belly) pointing west. >> >> Equivalently, but with less stress on the passengers, suppose >> you are over the Indian Ocean, at (lat,lon) = (0,90). >> Then the reference frame for attitudes can be achieved via: >> -- Heading = south. >> -- Pitch = level flight. >> -- Bank = level flight. >> On 11/06/2009 02:48 PM, Tim Moore wrote: > You need to show your work :) The behavior reported above was observed using the feature I implemented whereby the orientation quats are exposed in the property tree. Erik committed the code, so anyone can easily replicate the observations. Also the observed behavior is entirely consistent with the apparent intent of the viewmgr.cxx code, as I read it. Note: Since there was some criticism of one of the property names I used, and more importantly some quite useful criticism of the underlying concepts and interpretation, I have submitted a follow-on patch that should fully deal with these issues. http://www.av8n.com/fly/fgfs/viewframe.patch > This doesn't agree with my understanding of > viewer.cxx, but I didn't write it. This is what I thought was going on: > > The basic reference frame for all geometry is your Earth Centered - Earth > Fixed > frame. Right. ECEF is the first item on my list of reference frames documented at http://www.av8n.com/physics/coords.htm I reckon the real issue here is not ECEF itself, but rather the fact that as mentioned at http://www.av8n.com/physics/coords.htm#sec-orientation to describe the orientation of a body in space, you need *two* things, not just a set of coordinates (and the vector basis induced by those coordinates), but also a set of identifiable axes attached to the body. If you use the conventional aviation body axes, i.e. X=forward, Y=starboard, Z=belly then the standard orientation, achieved by aligning the body axes with the ECEF axes, corresponds to flying at (lat,lon) = (0,0) with nose = vertically up starboard wingtip = east belly = north > After this, the rotation from an X-forward Z-down frame to the OpenGL > Z-back Y-up frame is added in. I agree with that ... except perhaps for the words "after this". My point here is that viewmgr.cxx converts to OpenGL coordinates fairly early ... and in particular Erik's new code passes around the OpenGL representation and does lots of calculations using that representation. Quite understandably, he found some of this surprising and confusing. In particular, if you align the OpenGL axes i.e. Xprime=starboard, Yprime=top, Zprime=aft with the ECEF axes, then you get exactly the orientation described in my previous note and quoted above. It may seem implausible, unconventional, and/or inconvenient, but it *is* what the code is using. The more unconventional and implausible something is, the more important it is to document it. My recent patch contains a bunch of explanatory comments. Also, in my recent patch, I took steps to cancel out the OpenGL transformation, so that the exposed quats use the conventional aviation body axes. This should make it easier to interpret the displayed properties. I realize most folks were not born with the ability to look at a quat and understand what it means, but it is a skill that can be learned. -- Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Maritime Models
Hey, if someone wants to do the U.S.S. Lexington (CVN 16) I've got lots of pictures. :-) > -Original Message- > From: Vivian Meazza [mailto:vivian.mea...@lineone.net] > Sent: Saturday, November 07, 2009 10:55 AM > To: 'FlightGear developers discussions' > Subject: [Flightgear-devel] Maritime Models > > Hi All, > > Alexis does it again: > > ftp://ftp.abbeytheatre2.org.uk/fgfs/Maritime/deck-park.png > > > Vivian > > > > --- > --- > Let Crystal Reports handle the reporting - Free Crystal Reports 2008 > 30-Day > trial. Simplify your report design, integration and deployment - and > focus on > what you do best, core application coding. Discover what's new with > Crystal Reports now. http://p.sf.net/sfu/bobj-july > ___ > Flightgear-devel mailing list > Flightgear-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/flightgear-devel -- Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
[Flightgear-devel] Maritime Models
Hi All, Alexis does it again: ftp://ftp.abbeytheatre2.org.uk/fgfs/Maritime/deck-park.png Vivian -- Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
[Flightgear-devel] ATC services for FSWeekend...
Hello all -- sorry about my abrupt exit this morning -- especially to you, Jomo, whom I feel I left holding the reins. To be honest, the level of chaos was just too much for me. I'm happy to volunteer ATC services for events where the participants are all attempting to work within the system, but when it becomes a free-for-all I just don't feel like I can manage. I apologize to anyone whom I may have let down and hope that the rest of the event goes well. I will probably participate as a pilot at some point. Sorry again, and thanks. Sincerely, -R. (MD-Terp) Robert M. Shearman, Jr. Transit Operations Supervisor, University of Maryland Department of Transportation also known as rm...@umd.edu -- Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
