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Expandable 3dof racing rig

Discussion in 'DIY Motion Simulator Projects' started by acemanmat, Nov 16, 2016.

  1. acemanmat

    acemanmat New Member

    Joined:
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    Wants and needs...from a complete newbie making notes and drooling along the way.

    To build a upgradable 3dof... Racing simulator

    Stage 1 get racing by buying wheel, peddles,shifter. Hand brake Up grade computer as needed. Build mdf pod cockpit to mount new gear..

    Stage 2 complete design and theory test 3dof rig including design of surge and traction loss tables.
    Stage 3 build 3 dof
    Stage 4 build 4&5 dof being traction loss and surge.

    Budget no more than $ $10,000 Aus for software and hardware.

    Rough outline of chosen hardware

    Fanatec steering and peddles
    Fasetech rc3 3dof
    Handbrake?
    Occulus drift vr or similar
    Buttkicker
    Motion dynamics 12v dc motors worm drive number 19
    12v, rated g-box speed 42, 27 amps, 5.7 kg, 75nm , 3200rpm, 75:1 ratio
    Jrk run to 250 watts as amp spikes above 40 12v12
    12 v 50 amp power supplies 1 per motor (4-5)
    Potentiometer ppc 27 from megaton

    1 Front and back surge, created by a sliding surge tray first /base layer

    2 Traction loss. Created by front mounted pivotal point and rear sideways rollers.
    2nd level. Travel distance to be determined.

    3 down and up pitch,
    4 tilt over roll.
    5 heave direct up and down

    3 4 5 is via a triangulation base pale with 120 degrees of separation between mounts

    Estimated weights...
    Sliding surge base 25 kg
    Traction loss bed 25
    Complete 3dof driver pod with all hardware 80kg
    Driver 100 kg
    With 70mm crank length ctc.
    Motors with
    45 mn / .07m = 642.9 newtons. 642.9 / gravity 9.80665= 65.5kg
    50nm / .07m= 714.5. Newton 714.5/ 9.80665= 72.8kg
    55nm / .07m= 785.7 newtons 785.7/ 9.80665= 80.1kg
    **75nm/.07m= 1071.4 newtons 1071.4/ 9.80665=109.25 kg**
    So I need a minimum of 55nm of torque for each of the 3dof pod.

    Motor rpm to based of a maximum need of 700mm/second.seems way to much?
    Linear velocity works out to be .307 which is pretty good

    Magnitude of max torque is 65.12Nm
    With No mechanical loss after taking into effect gearbox ratio
    Mass.kg 78 * acceleration.m/s. .307 = 23.95 newtons to move

    Weight above motor shafts is 78kg X gravity 9.8 n= 765 nm just to move?
    Motor torque 75nm / ctc (.07m) = 1071...
    Mechanical loss could not be more than about 30% or it won't work...
    Worried about mechanical loss with worm drive systems. Do I need to think about scn actuators?
    I could change the length of the ctc arm in order give greater magnitude of torque, thus mitigating worm drive mechanical loss.

    3600rpm/75:1 with 40mm CTC at 42rpm gives a linear velocity of 0.1759m/s with 1875 Newtons
    3600rpm/75:1 with 50mm CTC at 42rpm gives a linear velocity of 0.2199m/s with 1500 Newtons.
    3600rpm/75:1 with 100mm CTC at 42rpm gives a linear velocity of 0.4390/s with 750Newtons. To slow
    I'm finding (mot) magnitude of torque is not altering.
    40mm ctc = 64.95 nm mot
    50mm ctc= same
    100mm ctc= same
    So I think I have balls up that sum.. Yep need help with this bit.

    Example with motor number 19.from table
    [​IMG]
    75nm / .05m(ctc) = 1500 nm (force of magnitude)
    1500nm / gravity 9.806 = 152.96kg
    Rpm to Linear velocity (radius.05 * rpm 42 * 0.01472
    .2199 linear velocity speed of awesomeness

    Magnitude of max torque using hyperphysics
    64.95 nm of max torque. Based on 60 degrees either direction from horizontal. 120 deg of rotation in total.

    Motors for pod need to move estimated 180 kg/ 3 = 60*1.3(safety margin) =78kg each
    Motor for sliding base needs to move 20+25+180=225kg*1.3= 293kg but is lateral force only?
    Motor for traction loss needs to move 205kg*1.3= 267kg sideways only lateral force?
    • Like Like x 1
    acemanmat, Nov 16, 2016
    #1
  2. speedy

    speedy Well-Known Member

    Joined:
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    Alexandria , Egypt
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    My Motion Simulator:
    3DOF, AC motor, Arduino, Motion platform
    Nice ... you can easly hit the spot now.

    More pictures please so we can get the idia correctly .
    And you already know that we like pictures :p .
    speedy, Nov 16, 2016
    #2
  3. acemanmat

    acemanmat New Member

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    More than happy to post images and links that I have used to get me to this point but I can't post them yet being a newby spambot. I will draw it in auto cad as that's what I have and sort of know how to use. For the moment ideas are stuck in my head while the computer is in hospital getting patched up.
    • Like Like x 2
    acemanmat, Nov 16, 2016
    #3
  4. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

    Joined:
    Jul 13, 2014
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    Occupation:
    Innovative tech specialist for NGOs
    Location:
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    150,578Coins
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    +11,017 / 55 / -2
    My Motion Simulator:
    3DOF, DC motor, JRK
    A plan of your intended design would be most helpful, that way members can give advice on any potential design issues prior to construction.

    You make mention of the Fasetech rc3 3dof in your initial post, which is a yaw design rather than traction loss. Is that what you had in mind design wise or proper traction loss design with surge?

    If you intent a traditional traction loss design with surge then have a look at @Boomslangnz's project thread: https://www.xsimulator.net/community/threads/motion-sim-w-surge-traction-loss.5950/

    And @SeatTime's original rig: https://www.xsimulator.net/community/threads/seattimes-dc-motor-sim.5024/
    noorbeast, Nov 16, 2016
    #4
  5. acemanmat

    acemanmat New Member

    Joined:
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    Good pick up noorbeast. Originally I came across fase tech rig and thought, yeah that's a good thing but as I learnt more from other members. The more I decided it wasn't what I was after. I'll go check out the other 2 links now.
    Traction loss with surge....one day.....
    • Like Like x 1
    acemanmat, Nov 16, 2016
    #5