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G-SEAT

Discussion in 'DIY Motion Simulator Projects' started by gforce, Jul 26, 2020.

  1. Trigen

    Trigen Active Member

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    One other idea that i use to combat the head movement is to use the Virtual tracker with OVRMC and set up a dummy rig to compensate. I use that to great effect to simulate inertia effects when just using my G seat. Swaying from side to side and forward on braking etc.

    Cant beat the sensation of something moving behind you back though.

    Edit: I see you have probably experimented with this already
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    Last edited: May 2, 2021
  2. RowanH

    RowanH New Member

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    Hey mate - just checking in here catching up on all my sim reading. Well done @gforce, love your different take on the g-seat again. Good tip on the better gearboxes, tempted to try them. I looked at all your drives and my ears started involuntarily ringing :). Had to smirk - we've all thought 'safety, sh*t this thing could hurt us!'

    I'd love to think if we could all share the same workshop and have our combined access to services/equipment/ideas/thoughts what we could pull together. Very envious of some of your tooling. It would be epic !
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  3. Trigen

    Trigen Active Member

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    Hi there!

    So being bipolar and gone manic i finally got the energy, well a million times that to experiment and add surge to the seat. So thanks for the inspiration. I hope you get to use yours in between the nappy changes.

    I dont know how much experimenting you have done but I have to say though in the quest to remove false cues if you have a fully moving bottom seat you cant really get things properly cause its in reverse as it pushes you into the seat. My solution to this is to have a moving panel in the seat itself while only a small part of your butt rests on very thin panel on top that your pillow can also slide over. Currently i dont have the over panel implemented but if my posture is good and my body isnt actually moving this is very very convincing. I'll have to do more testing to see if i actually need that. Maybe just a much smaller moving plate will also do the trick

    Ps sabertooth 2x32 went haywire again at the end so ignore the flap.

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  4. cfischer

    cfischer Active Member Gold Contributor

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    Im having trouble visualizing your idea. I see the thin panel in the video that moves with surge. Maybe it will make sense when you get the over panel part implemented.

    If you look at how I did this effect the whole seat is tilted 25 degrees back and slides on the horizontal plane. This means that you are more shoved back into the lower part of the seat. There is little shear between your butt and the seat and I think this is key. It looks to me like you will have a lot of shear with your panel. Maybe I am wrong.
  5. Trigen

    Trigen Active Member

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    Oh im just terrible at explaining things so no worries. I also have no idea how yours actually feels so im just going with what i see.


    First off i love what you have done so dont take this as anything against it.

    I did try it more like your setup at first but it just felt wrong. What happens for me is when i press the brake hard i get pressure in my back anyway but the flaps slam backwards so i feel like my upper body is being thrown forward. When the slider moved forward (moving my lower body) the pressure under me feels like im moving backward in the seat (acceleration cues) . My lower body also moved away from the seat while the upper body stays put and i felt like i was being lifted out of the seat

    To me this is not what you want. You want the shear and pressure moving against you on braking while your lower body is generally static. Braking for me is the strongest force. What it looks like to me is that you don't get much if any shear/movement underneath you which is probably why you don't like to have any brake force. You can get the pressure of course but since the whole thing is moving you get to much pressure in the back instead of just under you on braking. We do of course have different ideas and implementations of things and that's great but id argue that having the forces in reverse which is something one should try to avoid.


    What i am leaning against which i think will be the easier implementation is to move the panel to the front so i sit in the back part and not on the plate at all. I will have to experiment with it to see if i should still sit on the plate or not to see what gives the best feel but its important to not move the body much. I do want the shear because when you hit the brakes the panel should move backwards creating the illusion of being moved forward/pressure . And the opposite as you hit the accelerator.

    I will move the sliders all the way out to the sides and have the link under the seat. You can see i have cut a slit already. I will also change the plate to thin steel and have a 10 degree tilt on the pillow.

    My body will be static and the slider will provide the pressure.

    gseat surge.jpg
    Last edited: May 6, 2021
  6. cfischer

    cfischer Active Member Gold Contributor

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    I really don't like shear. I tried it both on the seat base and the torso. I don't find the resolution high enough nor the cue very convincing. I'm all about the really high pressure. Seat bucket surge for me moves the hips back (like an inch) with lots of force (and speed) during forward acceleration. You feel it in the lower seat back as well as you're whole body jolts (please remember that its relative for each car). As for breaking, the seat bucket doesn't provide any useful information for me, so it doesn't move under breaking (after final tuning). I get tons of breaking information from my belt tensioner that pulls all 4 belts at about 60lbs each (max). It can take my breath away. Which I dig.

    Since you are after shear and I am after pressure, your motions are opposite from mine. And since your motion is in plane with your seat you can only achieve shear. As you and others have said, personal preferences can be different. Best thing to do is try everything yourself. Easier said than done!

    All in all, it is fun to discuss.
  7. Trigen

    Trigen Active Member

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    Fair enough and yeah, with DIY you can do exactly what you want! And that's the cool thing! Im sure this is far from the end result and i may end up tilting it more. Ill be adding side flaps later on same as you. Grabbed a couple of sheets of aluminum today. I also got a belt that leaves me quite sore after a race which is just awesome.

    I ended up with ordering 20:1 gearboxes from the shop you suggested but not in stock so im guessing 6 weeks. Thats the time needed to get my 1930 motors anyway. Looking forward to testing that
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  8. Trigen

    Trigen Active Member

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    I quick question about servo drives and gearboxes. Do you have a point on the chair which you move everything to as you would actuators? I am using your fantastic Mega sketch to drive things now. I'm assuming there's no big changes needed?

    On a side note i installed MD30C motor controllers instead of my Sabertooths (Could never tune it right) today and it was night and day difference. Rock solid and super easy to tune. I suddenly have detail even with the gearbox slop on my wheelchair motors ! I can only imagine how epic the servo drives will be.
  9. cfischer

    cfischer Active Member Gold Contributor

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    I am building a steel chassis right now that has linear actuators to move heave pitch and roll. Is this what you're asking?

    Don't know what sketch you're talking about. Do you mean cubexxx sketch to run aasd15a with the mega?
  10. Trigen

    Trigen Active Member

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    Sorry

    I was curious how you set up the servo drives (home position) with the sketch as it does not have a auto calibration but i seems my memory got the better of me. Its of course Cubexx sketch for the 15a drivers. My apologies.

    Looking forward to seeing the chassis once you get it up and running though! I happen to have a machine shop i worked at some years back just 10 min away so ill probably be borrowing some of your designs. Cant really go there and experiment but having a clear picture on how to do it works
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  11. cfischer

    cfischer Active Member Gold Contributor

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    If I was using cubexxx code for a g seat I would just manually push each paddle and piece back to "home" with your hands before powerup.
  12. Trigen

    Trigen Active Member

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    Im curious. If any what are you doing for traction loss? As you mention Mover only got yaw and in Simtools i needed to write my own plugin to have the flaps go down when (Preference. You could use default too) or just before i actually lost traction. I would of course prefer to use only Mover but both options dosent really work that well with flaps. With your Torso mover or a back on sliders it does work better, I experimented a lot with that earlier. For myself now though im considering using 2 actuators for a 2 axis sway/TL table for the whole rig unless i can find a better solution for just the G seat. You do sort of get a good feel trough sway for what the car is doing and how likely it is to go off though.
  13. cfischer

    cfischer Active Member Gold Contributor

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    Im planning on real, one to one, continuous yaw about the center of gravity, which would include traction loss.

    The only other system I've seen like this is force dynamics.
  14. Trigen

    Trigen Active Member

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    I had a peek on Force dynamics and i guess its mainly space constraints that are the issue. Apart from the power transfer trough some kind of brushes/brushless it isnt complicated at all. Just need to stick the computer and all that on the rotating table and off you go! I guess it depends on how many turns of continues motion you'd want or if you can get away having just normal power and unwind cables after xx amount

    Would definitively be the top addon to have your own little centrifuge in the house. I often forget if i turned on my peg leg or not the last couple of days cause with 4 flaps and surge in the seat i often cant tell! I find myself thinking of that G helmet system again haha... I see Cubexx has made sketches for continues rotation for the Mega and servo drives which would run that very well without gearboxes or very low ones
    Last edited: May 11, 2021 at 17:25
  15. cfischer

    cfischer Active Member Gold Contributor

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    Yep Cubexxx made the sketches per my request/donation. Slip rings are cheap. The only thing that should hold us back is the answer to the question, "Is yaw worth all the trouble?" I'm going to try and find out.
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  16. Trigen

    Trigen Active Member

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    Hope to see some grand ideas come to life mate!
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  17. Erik Green

    Erik Green Member

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    Just watched you latest video........... Pretty amazing! Now you need to start detailing how you go about tuning all this. Are you still driving it with sim tools? Could you outline how you handle the kinematics of the torso mover?
    Very nice and inspiring work.
  18. cfischer

    cfischer Active Member Gold Contributor

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    Thanks for the kind words! Tuning is pretty easy in flypt mover (would be in simtools too). The kinematics of the torso mover are the exact same as a typical 2dof seat mover rig built on this site. You allocate travel on a swing arm for both surge and sway, they are added to together to obtain the final motion.

    I used the same technique for the motion on the parts I posted about on post 38 in this thread.
    https://www.xsimulator.net/community/threads/g-seat.15035/page-2#post-207868
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  19. Erik Green

    Erik Green Member

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    Thanks for the feedback. Seems pretty obvious once you mentioned it. Going to be using 750W 80ST motors as I got a good deal. Pricing planetary GB's I see that Lichuan has good pricing on their 10:1 single stage's (with lowest backlash). Is 10:1 too low a ratio to control well enough?
    The torso mover looks to be an excellent way to cancel out the false cueing from the side paddles. Would like to have both front and rear TL/Sway on my setup since I have all the linear bearings and leadscrews I need. But its 2 more motors......... And I'm guessing full body sway would not work as well to cancel the false cues from the side paddles.
    Last edited: May 13, 2021 at 05:47