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Pneumatic G-seat project.

Discussion in 'DIY Motion Simulator Projects' started by T R Para, Feb 17, 2020.

  1. T R Para

    T R Para i make stuff up

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    My Motion Simulator:
    AC motor, 6DOF
    I have been working on an air driven g seat.
    It consists of a 1hp compressor, 16 air wedge bladders (4.92"x 11.02") , 6 Festo MFH-3-1/2-S Solenoid Valves (maybe more), 24 vdc power supply for the valves, and a semi DIY control board. No Arduino boards is needed.
    I have been testing the system using the NoLimits 2 roller coaster and Simtools.

    4 air bags are duct taped together to form the Heave bladder.
    4 airbags are taped together for the Surge bladder.

    2 airbags are placed on top of each other to double its height when filled and form the seat sway bladder.
    A set of these are place along each side of the heave bladder (one on the left and one on the right) 4 airbags total.
    2 air bags are taped together end to end to a form side sway bladder. They are mounted along side of the surge bladder (one on each side 4 bags total)
    Lots of fittings and 20 meters of tubing..
    The control board is based on a Mini USB 24 Channel Servo Motor Driver Controller Module.
    I will post some pics and links.

    www.amazon.com/gp/product/B00TDNKBMC/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1



    www.ebay.com/itm/Winbag-Air-Wedge-Pump-Shim-Inflatable-for-Door-Window-Fitting-Joinery-Carpenter/392383373953?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649


    Attached Files:

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  2. RacingMat

    RacingMat Well-Known Member Gold Contributor

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    My Motion Simulator:
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    Good project! When you need to deflate the bladders, you open the exaust, is it noisy?

    Eager to see that rig with pneumatic heave !! :popcorn
  3. Zed

    Zed VR Simming w/Reverb Gold Contributor

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    My Motion Simulator:
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    I really like the idea of multiple cells acting together. I would guess that would give faster inflate/deflate.
  4. Sebj

    Sebj Active Member

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    Curious to see how you make out with this project
  5. Markku Lorenz

    Markku Lorenz Member

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    Hello

    In 2019 i build an pneumatic driven "air hammer" for my blacksmithing Projects.
    Well, with enough air you should move a lot of weight.
    AND fast.
    I think, that can be a really good story...
  6. T R Para

    T R Para i make stuff up

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    My Motion Simulator:
    AC motor, 6DOF
    RacingMat
    The solenoid valves exhaust whenever they are not powered up with 24vdc.
    The exhaust is rather loud. As you know you can put mufflers on them and it helps a bit.
    A more involved exhaust muffler would make it a bit quieter.
    I always use a Vr head mounted display when playing so the noise is not very noticeable due to the integrated headphones .


    Zed
    The air bladders have truly been a learning experience.
    I built some air bladders using TPU impregnated ripstop nylon.
    A single "seat sized" bladder took 5 seconds or more to fully inflate. The multiple bladders are much quicker. Right now the seat heave bladder fills in a 1 second or less.
    Some general info::
    Air Pressure is limited to 15 - 20 psi.
    The bladders are rated to 37 Psi.
    Automobile tires typically are filled to 32 Psi, so 20 Psi will lift your butt just fine..:eek:

    You need to have some type of air pressure regulation..
    High air flow rate is very important versus air pressure which is not.
    The Diy control board shown is built from low cost easy to aquire components.
    No programming is needed but some soldering is..
    Simtools game engine works perfect.
    The board shown can control 8 solenoids.
    :):)

    Attached Files:

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  7. RedRider

    RedRider New Member

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    I’ve been considering that compressor as well, given how quiet it is. Curious to see if 3 CFM meets the needs of all your bladders. If so, I’ll jump in and do something similar.

    Seems to me this is much more economical than the stepper panel route, and it can be much more easily adapted to the individual seat/user. I’ve got a 32” waist, or else I would have sprung for the GS-5. This solution is less responsive (particularly with deflation) but with all the comfort of a normally padded seat not made for the average American.
  8. T R Para

    T R Para i make stuff up

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    My Motion Simulator:
    AC motor, 6DOF
    Jason you may be right. 3cfm most likely will not cut it for some situations.
    I paid $137 for the 3cfm compressor on sale.
    Amazon has a 6cfm quite compressor for $335 (California Air Tools 10020c).
    I may get a second 3cfm if needed . lol
    You are also correct about the deflation time.
    If you are doing a flight sim I don't know you will need as much air as the a driving sim will need.
    In the roller coaster sim with a 2min 30 sec run, it pretty much depletes the 3 cfm compressor.
    It may be possible to "tune" the system for more efficient use of the compressor.
    I believe it was in RacingMat's thread they showed a commercial G-Suit that appeared to have big HP compressor with at least a 100 gallon tank.
    I will be doing more tests soon as I am getting close to the projects completion.
    • Like Like x 1
  9. RedRider

    RedRider New Member

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    Yeah, Sorry to hear that. I’m not that smart on pneumatics, but I was thinking a potential solution would be to use a closed loop as others have. Can anybody confirm if a pneumatic cylinder can be used in reverse? i.e. drive volume using the piston? If so, given the piston seal is up to it, could you not quickly inflate/deflate a similar volume bladder with minimal loss of air?

    If so... maybe have a pneumatic cylinder drive another cylinder in reverse mode? Two cylinders per bag group. Not optimal, but just something I’ve been considering.
  10. T R Para

    T R Para i make stuff up

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    My Motion Simulator:
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    Yes you can. I looked into the cost of using such cylinders but the cost looked to be too much. But it would work!
  11. RedRider

    RedRider New Member

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    I see what you mean after looking at amazon... maybe $150 per bladder in cylinders, and that’s a log of bags you’re running!

    I wonder how hard it would be to make your own. If you could customize the volume for a given stroke, you could drop the price significantly per bladder loop (one air cylinder pair per loop).
  12. RedRider

    RedRider New Member

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    I’m curious... after seeing your other gseat thread, what was the reason for going pneumatic? Paddles looked to work well, I’m leaning that direction myself due to lack of vacuum, but maybe you were not satisfied with actuators?
  13. T R Para

    T R Para i make stuff up

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    My Motion Simulator:
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    @RedRider ...
    I was pretty happy with the actuator/servo G-seat. The problem with it there is really no feeling of heave.
    The Back paddles worked very good for sway effect. And the same Back paddles worked ok for the surge effect. Not great but just OK...
    The Seat paddles were fine for sway effect. As a matter of fact they were awesome when running on the Daytona Speed track during the bank.... But they did not have any heave effect. Heave if felt in your butt. The seat paddles just squeezed your thighs....
    The Pnuematic G seat actually lifts you up about an inch or so. It can also transmit road bumps pretty good.
    It can also be transported to a different seat/rig without a lot of rework.
    I have since built 2 new simulator chairs and dismantled the original. (just part of the obsession!)
    The Actuator G-seat was hard mounted on the seat with a couple dozen bolts and holes needed to be drilled into the seat.
    I hope to post pictures of the near finished Pneumatic G-seat later this week.
    Two of the pieces I need are scheduled for delivery tomorrow. Then I should be about done with it...:)
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  14. RedRider

    RedRider New Member

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    Yeah, I would think hinged paddles would have that issue. I was considering lifting the entire paddle (no hinge) but now I’m thinking a platform actuator like sfx100 is a better way to do heave. Looking forward to your final review!
  15. SeatTime

    SeatTime Well-Known Member

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    My Motion Simulator:
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    Yep, which is why the base of my G seat, moves up and down for heave, left right for sway, forward and back for surge and also has paddles and pressure plates for applying additional pressure on the butt for all three. All done with actuators - no air bladders.
  16. dedraro

    dedraro Active Member

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    This is a nice project, I have already seen a guy do something similar with the SFX-100 motors, I stay updated! :D
  17. T R Para

    T R Para i make stuff up

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    My Motion Simulator:
    AC motor, 6DOF
    I believe I have solved the remaining problems with my G-seat.
    The left/right side air bladders which are positioned on the vertical back of the G seat and provide the Sway effect did not really squeeze the Driver/ Pilot with enough force. The reason was the bladder had little to work against unlike the heave and surge bladders which rested against the seat back and bottom..
    I simply added yet another air bladder on top of the side/sway bladders which solved the problem. These new air bladders are not powered by the main solenoid controlled air system but are simply pumped up to the appropiate pressure using the small hand held bulb pump.. It works well and allows you to adjust side sway clearance for different sized pilots...
    I made a short unedited video of the air bladder action.
    It is being operated by a solenoid valve.
    The deflate speed is slowed down a bit due to the fact there is nothing pushing on it.
    BTW: 15 psi will lift a 95Kg load with little delay.
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  18. RedRider

    RedRider New Member

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    Nice. How does it compare to your motor driven gseat?
  19. T R Para

    T R Para i make stuff up

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    My Motion Simulator:
    AC motor, 6DOF
    Well there is no comparison in their lifting power. The air bladders are very powerful. The combined 4 air bladders in the seat for heave could probably lift 1000 lbs.
    Its not too hard to figure. Say each bladder is 10" wide by 4"deep. That is 40 sq inches. At just 15 psi that equals 600 lbs..
    There has to be a whole lot better way of doing it than 16 air bladders but this is literally my first stab at it and I can tell you that 2 months ago I did not know a thing about this stuff.
    I am lucky to be retired and still fascinated with this hobby @ age 67...
    I have a deep love of aviation even though I never got a pilot license.
    But enough of that!
    Here are a few pics of the solenoid valve assemblies.
    As I mentioned earlier it is all about rate of airflow not pressure.
    In the front of the picture is a set of high flow pressure regulators.
    150 psi input and up to 30 psi out.

    Next is a row of 4 high flow solenoid valves.
    2 are in parallel for the heave bladders and the other 2 are in parallel for the surge bladders.
    Next are a set of 6 medium flow solenoid valves.
    1 for the right side back sway.
    1 for the right side seat sway.
    1 for the left side back sway.
    1 for the left side seat sway.
    The last 2 may end up not being used.. so they are extras....
    Most everything here was purchased off E-Bay.
    I payed about an average of $30 USD for each valve which retail for $150 each new...
    The 5 air regulators cost me about $30 each also. And they to cost over $100 new.
    It took me a while to accumulate all this junk!

    Attached Files:

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  20. SeatTime

    SeatTime Well-Known Member

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    Hi @T R Para . Question: Are the fill for these bladders just on/off, or are you controlling the fill in some way?