[simpits-tech] Motion...
Craig Rochester
simpits-tech@simpits.org
Thu, 3 Apr 2003 06:46:25 -0500
Hi Mish,
I sure would like a 200 deg field-of-regard! :) This seems to be feasible for commercial airliners
where you have windows in the cockpit and can use discrete monitors or projectors. For fighter A/C
with a canopy, you'd need a dome(CAVE) projection system or very wide FOV HMD. AFIK, both these
technologies cost ~ 100K and up.
Craig R.
-----Original Message-----
From: simpits-tech-admin@simpits.org
[mailto:simpits-tech-admin@simpits.org]On Behalf Of Wg Cdr BB Misra, VSM
(Retd)
Sent: Thursday, April 03, 2003 12:57 AM
To: simpits-tech@simpits.org
Subject: Re: [simpits-tech] Motion...
Hi Craig,
Wider FOV becomes very relevant for lateral tasks (e.g., bank capture etc).
Roll rates and accels which look OK with a 120 FOV suddenly look too fast
for a 200 FOV (or real world a/c).
- Mish
----- Original Message -----
From: "Craig Rochester" <johncraigroch@msn.com>
To: <simpits-tech@simpits.org>
Sent: 03 April, 2003 5:00 AM
Subject: RE: [simpits-tech] Motion...
> Hi Erwin,
>
> I agree that the visual cues dominate for motion except that G-force cues
aren't provided by
> graphics in fighter combat. Of course a motion platform doesn't pull G's
either. The G-suit rig
> I'm using does fill this gap.
>
> >From my reading on vision systems and fighter simulators, 60 deg is about
the minimum FOV that is
> acceptable for military training. 90 degrees delivers good performance.
This is for HMDs where the
> wearer can look 360 deg. Higher FOVs were preferred by pilots, but didn't
result in significantly
> greater situational awareness or improved task performance.
>
> For a fixed display like a PS, I'd say 120 deg would be very constraining.
>
> Craig
>
> -----Original Message-----
> From: simpits-tech-admin@simpits.org
> [mailto:simpits-tech-admin@simpits.org]On Behalf Of Erwin Neyt
> Sent: Wednesday, April 02, 2003 6:39 AM
> To: 'simpits-tech@simpits.org'
> Subject: RE: [simpits-tech] Motion...
>
>
> Chris is right,
>
> motion-simulation = 90% visual + 10% real-motion.
>
> One very important requirement for the visual system: peripheral coverage,
> so at least 120 degrees, more is better.
>
> Erwin.
>
> > -----Original Message-----
> > From: Chris Brace [mailto:chris.brace@paradise.net.nz]
> > Sent: woensdag 2 april 2003 12:04
> > To: simpits-tech@simpits.org
> > Subject: RE: [simpits-tech] Motion...
> >
> >
> > If your really keen here is another link for you.
> > http://www.cadsoft.de/~kls/fltsim/
> >
> > This project is very cool and uses some ingenious ideas. Cost
> > is bugger all, but sadly there has been little movement (pun
> > intended) on it for a while now.
> > I'd love to put one of these under my F16-something or other
> > but in all honestly good visuals and simple motion queueing
> > would be a lot simpler and just as effective.
> >
> > I did a couple of hours flying in a full military sim a few
> > years back. It was an AirMacchi MB339, using a 3 screen
> > colminated display with a fixed (no motion) base. The
> > feedback from the controls, the sounds system and the visuals
> > were enough to fool me. I actualy got vertigo during a pop-up
> > from ground level to 5000ft and rounding off the top. I
> > suddenly had to grab for the canopy bow because I felt like I
> > was about to fall over the top as I rounded out and pointed
> > down to the ground again. It was a very good lesson about
> > visual being able to fool the senses.
> >
> > Chris.
> >
> > -----Original Message-----
> > From: simpits-tech-admin@simpits.org
> > [mailto:simpits-tech-admin@simpits.org] On Behalf Of Gordan Sikic
> > Sent: Monday, 20 January 2003 10:17 p.m.
> > To: simpits-tech@simpits.org
> > Subject: Re: [simpits-tech] Motion...
> >
> >
> > Hi,
> >
> > Joseph Fagner wrote:
> >
> > >Think about this for a minute (granted I realize this is probably
> > >overly simplistic and the math is infinitely more complex): Most
> > >software out there has the 4 axis of data (not to be
> > confused with the
> > >axis of evil) one might need for motion. Couldn't one just
> > write some
> > >software to read this data and translate that to motion?
> > The data to
> > >which I refer is (1) pitch and (2) roll (X and Y axis); via your
> > >artificial horizon instrument. (3) Yaw (Z axis), via your
> > compass and
> > >(4) altitude via the altimeter.
> > >
> > >
> >
> > It is not that simple.
> >
> > You need angular rates as well as accelerations. Making
> > motion platform
> > based on attitude of the AC would be waste, beleive me. Generally
> > speaking, with the motion platform one hopes to imitate (inertial)
> > accelerations that pilot feels. Simple example acceleration on the
> > runway during take-off. During that period pilot feels sustained
> > acceleration on his back. The sense of acceleration is imitated by
> > rotating the platform slightly backwards, so the weight of
> > the "pilot"
> > generates the force on the back. That shift is sudden, and later the
> > platform is slowly returned to middle position. Thus,
> > imitation of just
> > one linear acceleration is achieved completly different type
> > of motion
> > (sudden rotation, followed by slow return to neutral position).
> >
> > Other than this, you should think of something completly
> > different: Motion platfors are _very_ power hungry, you might
> > easilly end up with
> > facility which draws couple of tens of KW of power.
> > Yet another problem is safety. Think of the following: it is
> > very easy
> > to start the filre in the chitchen with electrical oven of
> > just couple
> > KW (or even less), and here you are dealing with much more powerfull
> > equpment.
> >
> > Yet yet additional problem are foundations, because something must
> > support complete construction, and take over complete forces
> > and moments
> >
> > generated by themoving platform.
> >
> > There are many problems, but this doesn't mean that there is
> > no sollution :) If you really want to make motion platform,
> > do read apropriate chapter
> > in "flight simulation", book that is mentioned few days before. It is
> > excelent reading, but be warned that it does not provide us with
> > sollutions, but presents the problems in very concise way, and just
> > guides towards the solution. But in any way it is a "must have" book.
> > I've been reading it from the cover to cover and all over again many
> > times :)
> >
> > Also check web for motion platforms where you will find some
> > standards
> > you should achieve. one url is www.fokercntroll.com, and the
> > other is
> > (if I recall correctly, I'm off line now) www.mug.com.
> >
> > Personally I'll take following approach:
> > Generaly, visual system provides low frequency sensations, and use
> > motion (vibrations to be specific) for the high frequency sensations
> > (like tyrbulence, or vibrations, ...). This is not as good as
> > well made
> > motion system coupled with nice visualisation, but it is
> > _much_ better
> > than wrongly made motion platform, and in any case infintelly safer.
> >
> > At the end one true story:
> > (I don't know the details, what kind of AC, how many degrees
> > of freedom
> >
> > in motion platform, nor how many pilots, ... :)
> > There was a project of evaluating different algorithms for driving
> > motion platform, and within the project many (profesional)
> > pilots were
> > flying on the simulatior, every flight with different
> > algorithm applied.
> >
> > Needles to say that pilots didn't know which algorithm was to
> > be applied
> >
> > for any of the flights. After every try, they were asked to
> > describe in
> > words how they felt, and to place a numerical mark. After the
> > data were
> > analysed, it turned out that many pilots (more than few, anyway) said
> > that the best results were achieved with algorithm "number
> > 5". The funny
> >
> > thing was that algorithm in question corresponded to the case
> > where the
> > motion platform didn'mtmove at all! Of course, pilots didn;t
> > know that
> > fact while "flying"
> >
> > >Jay
> > >
> > >-----Original Message-----
> > >From: simpits-tech-admin@simpits.org
> > >[mailto:simpits-tech-admin@simpits.org] On Behalf Of Roy Coates
> > >Sent: Friday, January 17, 2003 6:57 PM
> > >To: simpits-tech@simpits.org
> > >Subject: Re: [simpits-tech] Motion...
> > >
> > >On Fri, 17 Jan 2003, Brian West. wrote:
> > >
> > >
> > >
> > >> I have an excellent book published a few years
> > back. The title
> > >>
> > >>
> > >is "
> > >
> > >
> > >>Flight Simulation" by J.M.Rolfe and K.J. Staples, published by
> > >>
> > >>
> > >Cambridge
> > >
> > >
> > >>University Press, ISBN 0-521-35751-9
> > >>It contains all the mathematical models etc needed plus a lot more.
> > >>
> > >>
> > >It's
> > >
> > >
> > >>almost certainly out of print but a search of secondhand
> > book dealers
> > >>
> > >>
> > >might
> > >
> > >
> > >>turn up a copy.
> > >>If you can't find a copy come back to me . It's all a bit daunting
> > >>
> > >>
> > >though,
> > >
> > >
> > >>time and costwise for an individual.
> > >>
> > >>
> > >
> > >Thanks Brian - appreciate that. From what little research
> > I've done so
> > >far it has become quite clear the there is no fixed rule to motion
> > >simulation,
> > >there seem to be several schools of thought on the topic.
> > >
> > >It also seems clear that each method has its own weaknesses. I'll
> > >continue searching!
> > >
> > >Roy.
> > >
> > >
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> > >page. Thanks!
> > >
> > >
> > >
> > >
> > >
> >
> >
> >
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