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007 G-Seat: Ultra Compact/Servo Based

Discussion in 'DIY Motion Simulator Projects' started by Spit40, Jun 25, 2017.

  1. MarkusB

    MarkusB Active Member Gold Contributor

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    My Motion Simulator:
    2DOF, 3DOF, DC motor, Arduino, Motion platform
    I have the hinges mounted at the very edge of the flaps and 22cm apart. So it is not like on your drawing where the hinges are some cm away from the inner edge.
    And since these 22cm are a little more than the distance between the two lowest points of my pelvic bone, the flaps cause a pure squeeze effect without any heave.
    I did not make any experiments with orher setups though, and thus I cannot say what the optimal distance is. Maybe your setup does feel better, so that you may regret having changes it. But for me the effect is really satisfying as it is, and thus I will keep it.
    What I am not satisfied with are my current backrest flaps. I guess their hinge distance is too large, so that they tend to squeeze by back, which does not feel like surge. I will change this when I am back home after my vacation.
    • Informative Informative x 1
  2. Spit40

    Spit40 VR Flyer

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    @MarkusB I'd like to switch to your approach as i don't like the feel of the heave action on mine. Unfortunately my classic car seat has a narrow seat area. Not much more than 22cm in total. How wide are the heave flaps themselves on your rig?
  3. MarkusB

    MarkusB Active Member Gold Contributor

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    I don‘t have their width in mind and can measure it not before next Saturday. I think they are about 12cm, but I am not sure.
    But you can determine the required width:
    Mount two pairs of hinges on a wooden board in the desired distance (in my case it was 22cm, but yours may be different depending on your anatomy), and connect provisiory flaps (e.g. wooden planks) to the hinges. Then sit down onto the wooden board between the hinges, move the flaps upwards with your hands and check which part of the flaps that gets in direct contact with your body. This is your required flap width.
    • Like Like x 2
  4. MarkusB

    MarkusB Active Member Gold Contributor

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    @Spit40: Today I measured the size of my heave flaps and added the info in my thread.
    • Useful Useful x 1
  5. Robdog

    Robdog Member Gold Contributor

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    Hi @Spit40. I have built a GSeat for sway using your Arduino code posted earlier in this thread. The right servo doesn't go negative but the left side does. I am clueless when it comes to coding but I can't see why it wouldn't work the same for both when I review the code. Your notes on the code say the left side has not been scaled yet, is there something I need to tweak?

    Thanks for sharing your code, this is something I have been looking for.
  6. Andrew Lawrence

    Andrew Lawrence Member

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    Any chance you can do a video and show us your settings. I built one just about like Spit40's, was going to market them, but have found little interest. I won't say I know everything in and out, but I have set the seat up on a number of games. I might be able to add some insight.
  7. Spit40

    Spit40 VR Flyer

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    Its very dependent on what servo you use. I clip -ve input values but then you need to map to the range of movement you want your servo to move through. For that i had to modify the code and keep hard coding different numbers through the arduino editor, experimenting to get the mappings right for my servos and leverage setup. Does that help/explain?
    • Informative Informative x 1
  8. Robdog

    Robdog Member Gold Contributor

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    Thanks for the reply, it does make sense, I have been playing with the values to see if different ranges will fix the issue. The bit that confuses me is the right servo does exactly what I want it to but the left servo seems to think it has gone out of the limits when it gets to -22% on the slider and spins the opposite way by nearly a full rotation. Up until the slider reaches -22% it doesn't move which is correct. If they both behaved the same it would make more sense to me.
  9. Spit40

    Spit40 VR Flyer

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    Interesting. You should see no change between -22% and 0. Anything below zero should act like zero. Can you point to the code download you used so there's no confusion or just paste the arduino code into this thread for me to look at.
  10. Robdog

    Robdog Member Gold Contributor

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    I have attached the arduino code I am using.

    Attached Files:

  11. Spit40

    Spit40 VR Flyer

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    @Robdog the only thing I can think of is that you are not sending the data to the arduino in the way its expecting. Check the screenshots I put earlier for how I coded that interface page. It should send values between 0 and 255.

    Also try removing the #'s from this bit and the similar later bit. I haven't used the arduino dev environment for a while but it should show in a panel what numbers its receiving and the values it is converting to for the servo.

    #ifdef DEBUG
    Serial.print("read in ");
    Serial.println(actuatorPosition[currentActuator]);
    #endif
  12. Robdog

    Robdog Member Gold Contributor

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    I found the problem at last, as always it was a minor detail. I didn't include a ~ after the left side code in the interface screen, I thought this was to separate the instructions for the two sides.

    Thanks for your help Spit40 it works fine now.
    • Like Like x 1
  13. Spit40

    Spit40 VR Flyer

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    Good news. Glad you're up and running.
  14. Spit40

    Spit40 VR Flyer

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    Version 2
    The time has finally come to work on version 2 of my gseat. For a few months now I have had the heave flaps disabled. The reason is that I was running the motors way too hot (I could smell how hot they were getting) and the action was fairly unconvincing especially for flight. My thighs were grtting lifted but it was nothing like the sense of being pressed into the seat.

    The change I wanted to make was to use @MarkusB 's approach of a full depth heave flap (rather than front section only) with flaps placed so as to apply a side squeeze only rather than a lift action. Much less force should be needed for a squeeze.

    The reason for delay is that my bucket seat is so narrow i felt the only option was to switch seat which i couldn't bring myself to do. Here's the v1 design and you can see there's no extra width.
    IMG_0826.JPG
    I finally concluded i could peel back the leatherette and make some room by squeezing the foam with cable ties.

    IMG_0827.JPG
    This is version 2 prior to bolting everything together. The flaps are probably slightly wide so i'll be cutting them back a little once its all fitted and i see how tight it is.
    IMG_0828.JPG
    • Like Like x 2
  15. T R Para

    T R Para i make stuff up Gold Contributor

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    Hi Spit40.
    I wanted to check with you about the ASME -04A servo /12V~24V 260kg.cm 0.12s/60 degree sold by wingxine.
    I would like to start on my g-seat soon and it looks like servos is definitely the way to go. I am considering 2 per side for the heave and one per side for the surge. With 6 servos plus arms I am looking at around $500 US.
    That is pretty expensive for me.
    What do you think.
    Is this the best bang for the buck?
    Regards.
    Tom
  16. Spit40

    Spit40 VR Flyer

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    What type of heave action are you looking for? A genuine full seat lifting action takes a fair bit of power (possibly more than a gseat is capable of) so probably does need a pair each side. I'm using one servo each side but i'm flying not driving and am going more for a side squeeze rather than a lift. People making seats for driving sometimes focus on a thigh pressure only rather than full seat.

    In terms of servo power bang per buck, these servos take some beating if you can get a good price on them with low shipping fees.
  17. T R Para

    T R Para i make stuff up Gold Contributor

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    Thanks for your feedback.
    Being a newbie at this hobby knowing what I need let alone what I want is very challenging.
    I have read about all there is here on G-seats. So I am basing it on what seems popular and of course the design of the commercially produced unit by SimExperience.
    I believe the side squeeze and back surge is what I want to try.
    In my readings servo torque was always lacking.
    That is why I asked about the ASME servos.
    Your practical experience is much more informative than any specifications listed in an EBay ad.:nerd

    My rig is a 2dof wheelchair powered system.
    I have played racing sims mostly but I have a everything for DCS .
    If you think the ASME 280 Kg x .12sec speed are descent for this project then that is what I needed to know.
    Do you think 2 per side on the heave is overkill?

    Regards.
    Tom
  18. Spit40

    Spit40 VR Flyer

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    I prefer the simplicity of single servo per side and i'm using 2.5mm steel plate for my heave flaps so i think they can cope without distorting. Theoretically these 260kgcms should be enough unless you're really heavy but i measure them at more like 110kgcm. I don't know enough about the power needed for side squeeze. I will in a week or so. For thigh lift single servo wasn't enough. If you have space for 2 servos per side (i don't) it should be great and better than single even if single can just about handle it.
    • Informative Informative x 2
  19. T R Para

    T R Para i make stuff up Gold Contributor

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    My Motion Simulator:
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    I got 6 of the ASME 280kg servos with output arms coming. He made me a good offer and I am getting them for $58 usd each including the arms.
    I downloaded your sketches and will load up a Uno this week. I have a lot of rc servos I can try out on it.
    The specifications on Ebay says the max power draw is 5 amps ( x 24vdc) is about 125 watts per motor.
    I can see where the speed 550 motors would get hot after a little while...
    I think compared to R/c servos these are a bargain.
    I have flown R/c for many years so I did spend a few hours looking over HobbyKing and RC Groups classifieds.
    My hats off to MarcusB.
    He is literally our Knight in shining armor. The guy is amazing.
    But the Bowden Cable rig is a bit too intense for me.
    So again Spit40 thanks for doing this thread. Lots of good ideas.:)
    Regards,
    Tom
  20. Spit40

    Spit40 VR Flyer

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    That's a great price on the ASMEs. Who did you order through? I agree that the bowden stuff looks like it has a lot to offer but it's a bit too much fuss for me.

    Good luck with the build Tom. And have fun- i think most people here enjoy the building more than the using.

    Cheers
    Phil