[simpits-tech] ACES II Replica, G- cueing Seat.
Craig Rochester
simpits-tech@simpits.org
Tue, 22 Oct 2002 23:31:14 -0400
"Light and airy, organic if you will" that describes what I got from the I/V
transducer. I was very surprised that I didn't have problems with latency,
dampening and "squishiness". I thought for sure I'd have to build a complex
closed loop system with feedback from head/helmet pressure(that'd be a
bitch). The I/V's maintains a very precise pressure in the system. The
back-pressure produced by moving my head against the cylinder apparently is
sufficient feedback to do the trick. It felt like I had a book on my head
and not like being attached to a spring. I haven't tried it with Falcon4
yet as I'm too cheap to buy an $800 analog I/O card. I may try the G-Suit
servo regulator(essentially the same thing) in place of the I/V.
Verbal descriptions only go so far. I've thought about doing some
quantitative measurements of the performance. But hooking up the load
cells, pressure transducers, displacement transducers, and interfacing them
to a data logger is more complicated than the rig. :) Maybe it'd be worth
it for the "peer review".
I did a lot of web searches, particularly at the US Patent Office site, and
have yet to find and instance of an I/V used this way. I probably just
haven't looked in the right places.
I really appreciate your feedback. It's so inspiring to have someone talk
so fluently and insightfully about the nitty-gritty of this.
Thank You,
Craig R.
-----Original Message-----
From: simpits-tech-admin@simpits.org [mailto:simpits-tech-admin@simpits.org]
On Behalf Of Chris Woodul
Sent: Tuesday, October 22, 2002 10:50 PM
To: simpits-tech@simpits.org
Subject: Re: [simpits-tech] ACES II Replica, G- cueing Seat.
Hi Craig,
Cranfields seats are very mechanical in thier approach to cuaseing parts of
your body to move. They use strap and belt tensioning, pad movement, and
Z-Axis movement of the seat all in combination with the G Pants. By the way
to anyone doing G pants simulation..DO NOT SHEDULE the pants to inflate to
the real aircraft values, if you do that you can collapse the capilaries in
the persons legs. When you are pulling real G's its quite differnt than
sitting in a 1G environment.
Flight simulation GValves use a de-rated shedule to simulate the inflation
of the pilots actual G pants worn into the cockpit.
I read your webpage and I think its really clever. I think if you can
smoothely push and pull on the helmet that it could be quite "intuitive"
that there are forces actiing on you, especially since you are using a VR
environment with your system.
I am a real pilot and I fly partly with my Butt ( not just my inner ear..and
I know that other pilots on this forum will agree they do to) but even if
you are just acting on the head I think that the human brain is very
adaptable to feeling the inputs you will be imparting on it. I think some
important factors to consider is to "unload" the head tracking mechanics
sort of like a STEADY CAM so that none of the friction loads or weight loads
of the mechanism get translated thru the gimbals. I also think that you need
a fast enough system to kill any latency in the actuators..any delay in a
cue will kill the suspension of reality and possibly cause "simulator
sickness" on the user. Another factor is dampening any of the actuator
movements to feel Light and airy, organic if you will. You dont want the
movements to feel like a FIRM pick and place robot. Planes fly fluidly (
albiet with lots of force in planes like the viper.
Are you using any kind of load cells in the unit to measure output, and is
it a closed loop or open loop system?
Keep me posted, I will enjoy your progress!
Thanks,
Chris Woodul
----- Original Message -----
From: "Craig Rochester" <johncraigroch@msn.com>
To: <simpits-tech@simpits.org>
Sent: Tuesday, October 22, 2002 9:03 PM
Subject: RE: [simpits-tech] ACES II Replica, G- cueing Seat.
> Hi Chris,
>
> Thank you for you feedback on the G-cueing, it's a real thrill to have a
pro
> give feedback on this. Most of the time I feel like I'm working in a
> vacuum.
>
> Thanks for the link, I hadn't seen the Cranfield site. I noticed they
> mentioned loading. Is this the shoulder strap loading, or maybe helmet
> loading. I'm interested in pursuing a 3 DOF(maybe 6) helmet loading
system.
> I've done a little preliminary experimenting:
> http://pages.zdnet.com/johncraigrochester/vrvision/id12.html (photos at
> bottom). I'm already looking to do a HMD with head-tracking using a boom
> attachment to my helmet, so adding actuators to the joints is a logical
> extension(at least to me :)). I've had promising results using an
> electro-pneumatic regulator(V/P). I rigged up a crude 6 DOF boom attached
> to a helmet and mounted a long stroke pneumatic cylinder vertically to the
> rotation gimbal. I could move my head in all DOFs and still get a very
> constant applied force. I'm hoping the performance will be good enough to
> apply simulated inertial and G-forces, and also minimize the weight and
> inertia of the boom. I'm thinking I can calibrate the thing to "float".
>
> End of rambling,
>
> Thanks again,
>
> Craig R.
>
>
>
> -----Original Message-----
> From: simpits-tech-admin@simpits.org
[mailto:simpits-tech-admin@simpits.org]
> On Behalf Of Chris Woodul
> Sent: Tuesday, October 22, 2002 9:17 PM
> To: simpits-tech@simpits.org
> Subject: Re: [simpits-tech] ACES II Replica, G- cueing Seat.
>
> Hi Craig,
>
> I enjoyed reading the message thread you directed me to.
> The Company I work at makes the SIMULATED SEAT it self and CRANFIELD
> AEROSPACE in the UK makes the motor units, mechanisms and computers that
run
> the thing. We dont do the algorythms for them where I work. The Cranfield
> seat is purely electric, except for the G-Valve assy for the Pilots
G-suit.
> I do know that on the older G-cueing seats that used Pneumatics that the
> ability to evacuate the air that has been piped into the zone cushions was
a
> problem. I think you guys are quite smart and are definetly doing some
cool
> stuff.
> I dont have any of the numbers on operations of the unit ( and If I did, I
> am bound by a Non Disclosure Agreement with Cranfield Aerospace) If I can
> find any thing like what you are looking for in other industry literature
I
> will most certainly forward it to you.
> One neat thing about a G-cueing seat is that there is no need for WASHOUT,
> like there is with a 6-DOF Motion Platform. People need to understand that
> you cannot Simulate actual "G" with a G-cueing seat. You can however
> demonstrate the displacements and pressures on your body that are nice
CUEs
> to what is happening.
> The Cranfield people tell me that people who fly fighters "get it" but
> non-pilots dont always understand the cues being imparted on them.
> Other neat cues that are in the seat are accelerations, decelerations ( ie
> Braking and Afterburner use) also Gunfire High Frequency Vibration, and
> other areodynamic cues.
> If you havent already been there in your own pursuits of making a G-Cueing
> seat, here is the link to Cranfield.
> http://www.cranfieldaerospace.com/spg/simulation.htm
>
> Keep up the good work on your system, I am really impressed. As always
there
> are some really inovative and clever people on this fourm and thats why I
> love being a simpits member!
>
> Take care,
> Chris Woodul
>
> ----- Original Message -----
> From: "Craig Rochester" <johncraigroch@msn.com>
> To: "Simpits-Tech@Simpits. Org" <simpits-tech@simpits.org>
> Sent: Tuesday, October 22, 2002 3:40 PM
> Subject: [simpits-tech] ACES II Replica, G- cueing Seat.
>
>
> > Hi Chris,
> >
> > I've been reading through the archives and found your posts on the G-
> Cueing
> > seat.
> > I've been working on a G-Suit pneumatic rig with some guys from Norway.
> See
> > this forum
> > thread:http://www.simpits.org/forums/viewtopic.php?topicU&forum=1&start
> > <http://www.simpits.org/forums/viewtopic.php?topic=55&forum=1&start=15>
> (go
> > to bottom). I worked and worked to get a "regulator" that would exhaust
> > quickly. I finally stumbled on a rig that works well. I use a "quick
> > exhaust valve(QEV)" and a high capacity regulator. The air exhaust is
as
> > fast as the supply. Qualitative guestimates on performance:
> > Range of supply pressure = 0-5 psig
> > G-Force vs. G-Suit pressure- 1-9 G = 0-5 psig
> > 9 G - 8 G(5-4.5 psig) decrease take about 0.1 sec
> > 2 G - 1 G(0.5-0.0 psig) decrease take about 0.2 sec
> > 9 G - 1 G(5-0.0 psig) decrease take about 0.75 sec
> >
> > The bottom line for me is the feel of the G-Suit. I can feel 1/4 psi
> > changes, and the changes feel intuitively correct when I fly Falcon4.
But
> > I'm not a pilot and have never pulled Gs.;)
> > Do you have specs for the G-Seat latency requirements?
> > Regards,
> >
> > Craig
> >
> >
> >
> > _______________________________________________
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>
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