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Re: X-SIM 360° 3DOF Flight Pit with XPID and VR!

PostPosted: Mon 26. Aug 2019, 01:31
by asticher
Thanks to a RL Pilot i had a 2h flight at EDDM in a A-320 Level-D Simulator!
If anyone has also exp. with prof. flight simulators, i would be thankful to share them,
to develope better DIY motion sim concepts!

After 5 years of building my Frankenstein, the moment of truth had come. Would Frankenstein be a laughingstock
compared to this $12 million simulator? Would it all have been for nothing?
Would all the movements and forces have been completely wrong???
So let´s find out!
We did...let´s say some "uncommon" maneuvers in this 6DOF Hexapod :-D
But at first i was super flashed entering the Simulator, because everthing is just
like the real A-320 Pit! Even the seat fur!

The display is astonishing: It is not a monitor system but a 180° mirror system.
Although the textures are muddy and everything is a bit blurred,
the scenery looks very realistic. Especially the viewing angle is much more "real"
- difficult to describe.
Just once at the break from the downwind I noticed the optical borders of the system.
Night flying is especially brilliant thanks to the contrast.

We trashed preflight and startups checks - this was just about one thing: flying!
Again the big, ol scary question popps up: Is my 360° motion concept totaly wrong?
Will this High-Tech Sim blasting my Scrapmonster just away?

Let´s find out:
On Centerline, pushed the Thrustlevers to TOGA:
Damn...Acceleration feels so close to real, even constant.
The needed pitch level to simulate (max 14°) is not noticeable!
But then V1 and rotate:
Hmm...heave is missing. Near to nothing positive Gs. Not even OnSet Cueing. Why??

Time for some rudderwork:
Sway feels very realistic! No matter if levelflight or bank. Too bad that sway is
not simulated when taxing.

Ok, now basics: rolling.
Great OnSet Cueing when applying big inputs! But constant rollforces are only feelable up to 30° bank (system runs out of travelway?).
While performing a wingover it´s some Onset and then nothing -
but this should be realistic, i guess.
Unfortunately even light wing rocks causing no movement/accelerations in the roll axis!
So only the first roll input is simulated, then the system needs a certain time to simulate
the next input. Same issue with pitch.
Too bad, because this is very important for a realistic flight feeling, isn´t?

Brilliant simulated. The shaking, stutter and movements works very accurately and without any delay.
However no heave OnSet or Movement also, even with zero G.

Crash Dive / Climb Out:
Hardly or not at all noticeable. Also no OnSet Cueing. It was probably deliberately omitted
in order not to produce false Gs. According to the instructor, most Level D simulators behave like this.

One of a kind...Deceleration / breaks feels so real (same like T/O)
But at touchdown the wheel bump seems to be scripted (always the same).

Everything as in real, beautifully staged. Engine noises are great.
But wind noises are hardly perceptible for me.
Vibrations by engines at the TOGA are also missing.

Flight physics:
I can't judge...but certainly above any doubt.

My conclusion:
Super real haptics, great ambience, top of the pop for Procedures Training.
That is the meaning of this thing.
But to simulate emergencies, aerobatics or military - sorry nope.
Imho because this simulator use to less heave travel and provides only some roll/pitch accelerations.

May someone has exp. with Level D Simulators providing this things? That could be a gamechanger.

But in this configuration there is zero adrenaline even during extreme maneuvers like strong crosswind APP, stalls, wingover, etc.
And even though the ambience is so great, there is no fluffy cloud no.7 feeling through soft altitude/attitude changes.
Only App/Dep/Touchdown feels like real.
Except this few moments, using a solo VR HMD (without motion simulation) would may generate more (realistic?) flight feeling to some persons because of the 3D visual perception!

However this flight was a super nice experience! Thanks to all who made this possible!

Re: X-SIM 360° 3DOF Flight Simulator with VR

PostPosted: Thu 13. Feb 2020, 13:57
by asticher

A real life pilot took the flight simulator and put the pedal to the metal :eek:
No one's ever flown that hard, seriously. If you ever tried to fly in DCS under bridges or through the Burj al Arab, you know what I mean. The guy has never tryed VR glasses before, has never flown the L-39, has never practiced these maneuvers before and flies in the MotionSim as if it's a walk through the park!

Re: X-SIM 360° 3DOF Flight Simulator with VR

PostPosted: Wed 19. Feb 2020, 14:06
by asticher
I was already able to read out many G-Effects (e.g. speedbrakes, gear, buffets etc.) via the DCS Export.lua and wanted to use them for tactile effects with a body shaker (IBEAM).
Unfortunately the effects are different from Plane to Plane or partly not available at all. And also converting these G-vectors into reasonable sine impulses is really complex (even with x-sim).
But fortunately there is already a software for it!

It is called SimShaker Module and was developed for SimSHAKER JETPAD, but also works great for subwoofers and buttkickers!
I can feel every groove in the pavement while taxiing! Also buffets, airbrakes, touchdowns are great...and the GAU-8 OMG! :mrgreen:

You can adjust the effects perfectly for every pattern.
And the whole thing costs only 25 € + a cheap dedicated soundcard

Re: X-SIM 360° 3DOF Flight Simulator with VR

PostPosted: Fri 28. Feb 2020, 13:50
by asticher
Some say there are no negative or side forces while flying:
Now tell that again :-D

This video perfect shows how strong all forces in real live are (in aerobatic or millitary maneuvers).
It looks to me that negative forces are the worst, but also sway/side forces.

Re: X-SIM 360° 3DOF Flight Simulator with VR

PostPosted: Tue 14. Apr 2020, 01:54
by asticher
Unfortunately the belt tensioner shown in the video did not last long (I need extreme forces because i fly inverted in the 360° motion sim).
So I rebuilt it and now the belt tensioner works perfectly and generates 100kg traction. Below i added the sketch as PDF. What you need:

1x Emergency Switch 24V, rated 40Amps

1x 360° absolute encoder (Hall Sensor), analog, 0-5V

1x Arduino Uno

1x Sabertooth 2x25 H-bridge

1x DC brush motor 24V ; 350W ; gear output about 300 rpm ; with chain wheel 11 teeth.
If you'll get a (more expensive) gear DC Motor with 100rpm you will not need the chain (direct drive like in the sketch)
1x chain wheel with 27 teeth, hole diameter 25mm
1x matching chain approx. 50cm

2x Bearingblock (ball bearing) d=25mm ... 1589861281

1x drive axle d=25mm; approx. 13cm long

1x belt pulley with belt to control the encoder

1x 3mm Steelrope or extremely tear-resistant textile tape (safer!):

1x USB cable
10x various pin header cables

2x lead gel battery with min. 8Ah/12V

1x motor mounting

- Install and configure the free X-Sim software according to these instructions (be careful, use the Sabertooth variants):

- Connect the PC to the Arduino via USB cable. Connect Arduino to the encoder and Sabertooth using the PinHeader cables.
- Connect the DC motor to Sabertooth.
- Connect the two 12V batteries in series (24V) and connect them to the Sabertooth (CAUTION! Plus to plus otherwise it smokes!)

- Connect the DC motor to the Sabertooth (M1A and M1B)

If everything works in x-sim then you have to use the Export.lua from DCS. I will send you on request.

Then start DCS-Import.exe as admin (you always have to start x-sim before, otherwise it won't start).
Then start X-Sim Extractor as admin and configure the DCS-Plugin (help on request)
Press Play in the Extractor -> X-Sim Converter should start.

In X-Sim Converter under Interface Settings activate XPID. CAUTION: Motor will now start to rotate.

- Create an axis in the converter and install the G-Force effect (help on request)
- Then press Start in the Converter
- Start DCS. Commence mission.
- In X-Sim the Input Values should now arrive in the Math Setup.
The target line must change when you draw Gs for example.
- Now the engine should turn!

- Extend the battery with an emergency stop switch within your range!

- Now connect the textile tape to the 25mm drive shaft (hole drilled and tape pulled through and glued)

- Close the belts and test if the pull is not too strong and everything holds.

The belt/chain/drifeshaft can cut off your crown jewels and fingers because it runs directly between your legs.
If you accidentally pull too much Gs the belt can break the collarbone and even ribs!
-> make cable duct and protective cover
-> always haevg one hand on the EMG Switch
-> protect you encoder from chain/belt/anything
-> use a Sandbag first to test everthing is strong enough and everything works like expected.
-> use 12V firsttime or limit PWR to 50% in the Sabertooth Software

And now sit in, fasten the belt (with cutter in hand just in Case),
and have fun!

Re: X-SIM 360° 3DOF Flight Simulator with VR

PostPosted: Mon 27. Apr 2020, 20:00
by etundidor
He asticher,

Awesome work you have done there, hope it is working well now. Regarding it I have just a couple of questions:

Regarding your quote:

"Some Frame specs:
Pitch Axis shaft drive: d=80mm ; t=10mm; l=1200mm
Roll Axis shaft drive: d=60mm ; t=20mm; l= 300mm
Gears- and Accurators shaft drive: d=25mm (minimum!)
Pitch Axis frame round tube: d=140mm ; t=4mm (minimum!)
Main- and Roll Axis frame L-Profil: 40mm x 40mm x 4mm (better would be 30x30x4mm square profil!)

I use a big double chain for the Pitch axis. It is much easyer to assamble and to get the perfect gear ratio.
Also it is safer, sturdy and your gear box has less stress. The little more weight doesn´t really matter.

For the roll axis i use a direct drive axis through the gearbox. This reduce weight, latency, adds stiffnes, but ratio can´t be changed.

The Pitch axis has a one side bearing (U-Frame). This reduce roomspace but adds much weight and is not easy to build...ok and it looks just better *g.

Do you think it is possible to reinforce your post by adding some detailed pictures where we can figure it out from where you are taking some of the measurements there? You know for those of us that don´t got those skills and want to replicate your project???

Also, at least for the Roll Axis frame, what do you thing about those new Extruded Aluminum profiles, picture example attached?? Do you think they can be strong enough for the duty??

Again, great work there budy.

Take care


Re: X-SIM 360° 3DOF Flight Simulator with VR

PostPosted: Tue 28. Apr 2020, 12:31
by asticher
No, don't use aluminium, it can break very sudden and without warning (also most plastics).
Wear and tear is a saefty issue - even with steel. But with steel you mostly hear and feel it before something goes really wrong.

About the measurements: This are minimum sizes for proper safety. Everyone with Mechanical engineering knowledge should know what i mean.
Unfortunately, I cannot publish construction plans: The risk of someone accidentally killing themselves through misuse is too high.

Re: X-SIM 360° 3DOF Flight Simulator with VR

PostPosted: Sat 9. May 2020, 23:50
by asticher
I can now describe why a Gimbel Simulator (with 360°) creates such a different simulation experience:
In short, the proprioceptive system works without natural gravity and even under changing gravity.
Our body uses all joints, muscles, organ movements and hair roots as sensors.

Rotating changes in the position of our body receive particular attention from this sense,
as they quickly compromise our upright positional stability.
Abnormal body positions, especially those that are not produced by the own body,
cause severe stress by releasing adrenaline and cortisol.
This reflex is independent of visual perception, but is increased by blindness.

For proper bodyorientation in space, the vestibular system, the visual system and the proprioceptive system is needed.
Conflicting information from one of these systems leads to confusion, dizziness, even hallucinations.
*Note: When flying in darkness, the vestibular system gives false information because it is dependent on the correct 1G gravity.
The brain then tries to figure out who's right:
depth perception or sense of balance. Sometimes this goes wrong.

People who train the proprioceptive sense like pilots, martial artists or acrobats show
less or no reaction to the externally determined changes in position and rotation.

Conclusion: This is the reason why flying aerobatics in a 6DOF steward platform doas not feel right.
A steward platform can replicate realistic forces to an extend, but not the real position of the pilot.
And without the real position, no stress is not generated by the proprioception system.
So it is clear that a 6DOF steward is NOT a full motion simulator.