1. For downloading SimTools plugins you need a Download Package. Get it with virtual coins that you receive for forum activity or Buy Download Package - We have a zero Spam tolerance so read our forum rules first.

    Buy Download Package Now!
  2. Do not try to cheat our system and do not post an unnecessary amount of useless posts only to earn credits here. We have a zero spam tolerance policy and this will cause a ban of your user account. Otherwise we wish you a pleasant stay here! Read the forum rules
  3. We have a few rules which you need to read and accept before posting anything here! Following these rules will keep the forum clean and your stay pleasant here. Do not following these rules will lead to permanent exclusion from this website: Read the forum rules.

2DOF compact seat mover

Discussion in 'DIY Motion Simulator Projects' started by pipis2015, Mar 14, 2015.

  1. pipis2015

    pipis2015 over-boost

    Joined:
    Feb 18, 2015
    Messages:
    222
    Location:
    Athens, GREECE
    Balance:
    10,244Coins
    Ratings:
    +253 / 1 / -0
    My Motion Simulator:
    2DOF, DC motor, Arduino
    Hi all,

    I d like to share my 2dof seat mover project. Many of you may notice details that are inspired by your designs.

    It is designed as a detachable module that can be installed under my (static) gaming seat to convert it to a motion sim.

    It is designed to be as compact as possible.

    Its a "box" measuring 40x40cm width and 15cm height.

    The same design can probably be installed under any static seat to convert it in a 2DOF motion seat.

    parts list:
    • 12v 47A 575Watt server Psu
    • Arduino Uno R3
    • 9v ( 2.1mm centre positive plug) psu for arduino UNO
    • Pololu Dual VNH5019 motor driver shield for Arduino
    • 2x single turn Cermet 10k linear pots
    • 2x SWF VALEO 24v wiper motors
    • two 40cmx40cm steel plates + 15cmx15cm steel plate for Ujoint + 40cmx10cm bended steel sheet for motor chassis
    • USB isolator
    • AWD Suzuki vitara Ujoint
    • 12v 7Ah UPS battery
    Cost:
    300-350 euros

    So starting from this:
    static.jpg


    ...


    A Suzuki Vitara u-joint is probably an overkill but it was for free and its future proof.
    tilt.jpg
    ...


    First thing to do was calibrate and drill holes to the steel plate.
    SEAT ALIGNMENT ON STEEL PLATE.jpg
    early fitting preview.jpg
    ...

    Welding the U-joint's base.
    4WD Ujoint after welding.jpg ...

    Quick preview.
    motor chassis preview.jpg
    ...

    Closeup on the motor chassis.
    motor chassis instal.jpg
    motor chassis drlling.jpg
    motor chassis mounted.jpg
    ...

    Connecting rods (for motor)
    Dimensions:
    5mm thick
    2cm x 6 cm
    Drilling:
    10mm hole for motor
    8mm hole for rod-end bolt.
    m8 hi-fi rod-end.jpg
    center to center "C-C" distance is 2,5cm and 3,5cm (for motion adjustment purposes).
    2cm x 6cm connecting rod  drilling.jpg
    ...


    The holes require some more "refining" because their inner surface has to obtain a conical profile.
    When fitting the rod, make sure it sits very tightly on the "dents" of the axle.
    motor axle detail.jpg
    motor rod detail.jpg
    The easiest way to achieve this is to choose a "softer" metal alloy for the rod (not steel). So when you install it on the motor axle and as you progressively tighten the securing nut, the grooves of the axle will be "registered" on the softer alloys surface. Just don't go for a very weak alloy for this rod because it is a very crucial part of the motion transmission assembly.
    ...

    Powerplant assembled.
    360 1.jpg
    360 2.jpg
    360 3.jpg
    360 4.jpg
    tight fit2.jpg
    ...


    For the potentiometer,i tried to find the best solution amongst many presented on every possible project online.

    After trial and error i ended up with a custom solution from the r/c racing world(cogs with 45t/17t~2,7:1 ratio).
    I intend to use 90* to 100* (+/- 45* to +/- 50* from resting/center point) of rotation of the wiper motor axle, so this equals to 243* to 270* of rotation on the potentiometer axle.
    This way i can take advantage of full 270* potentiometer range -and arduino ADC range- for better resolution).

    The motors are designed to work From -45 degrees to +45 degrees from rest (horizontal rod) position, for more linear motion.

    A combined use of both motors can output a maximum of about :
    10 degrees LEFT or RIGHT(-10 to +10),
    OR
    5 degrees Front or BACK(-5 to +5),
    tilt on the seat.
    pinion gears.jpg
    The cogs have a fine pitch of 48p (small dents) to increase "sensitivity" for finer motion tuning.
    I have heared pinions make noise when they turn on some projects ... this is not the case here .. no sound is heard at all.
    ...

    Round head nuts ...Some drilling and some treatment with the lathe and.
    pot-cog nut-axle 1.jpg
    pot-cog nut-axle 2.jpg
    ...

    This s how it looks.

    AXLE ASSY.jpg
    motor pinion 1.jpg
    ...


    The potentiometer mounts are pieces cut from a fairly soft pvc drain pipe:
    1)They protect the pots in the rare case something goes wrong and the pots go out of travel.
    2)They electrically isolate the pots from the chassis.
    motor pinion 4.jpg
    motor pinion 5.jpg
    ...

    Some measurements.
    chassis dimensions.jpg
    triangle.jpg
    • Like Like x 9
    • Winner Winner x 1
    Last edited: Mar 21, 2015
  2. pipis2015

    pipis2015 over-boost

    Joined:
    Feb 18, 2015
    Messages:
    222
    Location:
    Athens, GREECE
    Balance:
    10,244Coins
    Ratings:
    +253 / 1 / -0
    My Motion Simulator:
    2DOF, DC motor, Arduino
    HP model DPS-600PB
    When the psu is plugged in the fan starts to spin but there is no power output.

    A “Y” cable to short pins 6-9-10, and...
    pins 6-9-10 short.jpg
    voltmeter.jpg
    ...


    Shorting pins 4-8 reduce the fan rpm to minimum. The fan still spins up when needed but stays quiet when the psu doesn't require cooling.
    fan hack.jpg
    ...

    Pololu Dual VNH5019 Motor Driver Shield for Arduino.
    Pololu Dual VNH5019.jpg
    Features:
    1. Low price … 49.95USD
    2. Compact … 2 Motor channels on a single pcb
    3. Arduino uno compatible and stackable(allowing for a more compact design)
    4. Works with up to 24volt VIN
    5. 12Amp continuous output current per channel (30Amps peak per channel)

    "short durations (on the order of milliseconds) of 30 A and several seconds of 20 A without overheating"

    6. 24Amp continuous output current for single motor connected to both channels(60Amps total peak)
    7. Ultrasonic PWM frequency 20kHz (works stacked on arduino uno)for quiet motor operation
    8. Reverse voltage protection
    9. overvoltage shutdown
    10. thermal shutdown
    11. Short protection


    Taking a look at the arduino board ... six ICSP pins seem to stand very close to the power input/output of the Hbridge (which sits on top of the arduino board).
    pin removal 1.jpg
    pin removal 2.jpg
    pin removal 3.jpg
    ...


    Phobya Thermal Pads.(high thermal conductivity of about 5W/mk, while also being flexible enough).
    Brushless fan .
    Aluminium heatsink.
    thermal tape.jpg
    heatsink fan.jpg
    heatsink 3.jpg
    heatsink fan 2.jpg

    boards 4.jpg
    ...

    Twisted power cables.
    powerlines.jpg
    ...
    a standby UPS battery in parallel with the psu.
    It is cheaper and more compact than a big 12v capacitor.
    Its puspose is just to assist momentarily the psu.
    stby battery.jpg

    ...

    Testing.
    test2.jpg
    • Like Like x 7
    Last edited: Mar 22, 2015
  3. Boomslangnz

    Boomslangnz Active Member SimAxe Beta Tester Gold Contributor SimTools 2.0 Beta Tester

    Joined:
    Oct 26, 2014
    Messages:
    344
    Balance:
    3,849Coins
    Ratings:
    +233 / 1 / -0
    My Motion Simulator:
    2DOF, 4DOF
    cool man, looking forward to seeing it all done!
    • Like Like x 1
  4. GIB SimRacing

    GIB SimRacing Active Member

    Joined:
    Feb 19, 2015
    Messages:
    232
    Location:
    Adelaide, SA
    Balance:
    1,389Coins
    Ratings:
    +242 / 0 / -0
    My Motion Simulator:
    2DOF, DC motor, JRK
    Very neat setup there, @pipis2015 . Everything looks solid enough while keeping the construction simple. Top work!
    Can I ask what you used to mount the Arduino board to the base? Is that directly mounted to what looks like a steel plate?\
    • Like Like x 1
  5. pipis2015

    pipis2015 over-boost

    Joined:
    Feb 18, 2015
    Messages:
    222
    Location:
    Athens, GREECE
    Balance:
    10,244Coins
    Ratings:
    +253 / 1 / -0
    My Motion Simulator:
    2DOF, DC motor, Arduino
    I have placed both the psu and the stacked boards on a 10x40cm plywood board. For stability and electric isolation.
    pics will follow when things are settled to a descent configuration.

    final testing.jpg
    • Like Like x 2
  6. GIB SimRacing

    GIB SimRacing Active Member

    Joined:
    Feb 19, 2015
    Messages:
    232
    Location:
    Adelaide, SA
    Balance:
    1,389Coins
    Ratings:
    +242 / 0 / -0
    My Motion Simulator:
    2DOF, DC motor, JRK
    Good idea. Yet again, simple and effective.
    • Like Like x 1
  7. bsft

    bsft

    Balance:
    Coins
    Ratings:
    +0 / 0 / -0
    Nice job. been there, done that
    [​IMG]
    [​IMG]
    [​IMG]
    • Like Like x 2
  8. value1

    value1 Nerd Staff Member Moderator SimTools Developer SimAxe Beta Tester Gold Contributor SimTools 2.0 Beta Tester

    Joined:
    Jan 9, 2011
    Messages:
    2,040
    Location:
    Zug, Switzerland
    Balance:
    4,256Coins
    Ratings:
    +2,879 / 10 / -1
    My Motion Simulator:
    2DOF, DC motor, JRK, Joyrider
    Nice sim, nice documentation. Thank you for taking the time to put it together! :thumbs
    • Agree Agree x 2
    • Like Like x 1
  9. RacingMat

    RacingMat Well-Known Member Gold Contributor

    Joined:
    Feb 22, 2013
    Messages:
    1,926
    Location:
    Marseille - FRANCE
    Balance:
    17,854Coins
    Ratings:
    +1,835 / 16 / -2
    My Motion Simulator:
    2DOF, DC motor, Arduino
    Very nice building and detailed post! :thumbs

    Eager to see a video and to hear how ultrasonic arduino PWM is more silent
    • Like Like x 1
    • Friendly Friendly x 1
  10. pipis2015

    pipis2015 over-boost

    Joined:
    Feb 18, 2015
    Messages:
    222
    Location:
    Athens, GREECE
    Balance:
    10,244Coins
    Ratings:
    +253 / 1 / -0
    My Motion Simulator:
    2DOF, DC motor, Arduino
    Thx Mat.

    All i can say is that thanks to your code and some provisional thinking from pololu (H-bridge PWM pins match arduino's TCCR1B) i managed to keep things simple, compact and quiet.

    The camera is placed 20cm from the motors.
    • Like Like x 4
    Last edited: Mar 15, 2015
  11. Fabgen

    Fabgen Member

    Joined:
    Dec 1, 2014
    Messages:
    72
    Location:
    France
    Balance:
    424Coins
    Ratings:
    +56 / 0 / -0
    My Motion Simulator:
    2DOF, Arduino, Motion platform
    Good job​
    • Like Like x 1
  12. noorbeast

    noorbeast VR - The Next Generation Staff Member Moderator SimTools 2.0 Beta Tester

    Joined:
    Jul 13, 2014
    Messages:
    11,642
    Occupation:
    Innovative tech specialist for NGOs
    Location:
    St Helens, Tasmania, Australia
    Balance:
    90,628Coins
    Ratings:
    +7,632 / 37 / -2
    My Motion Simulator:
    3DOF, DC motor, JRK
    Great job and thanks so mach for taking the time to capture all the build details, that is invaluable to others who would like to follow in your footsteps.

    When you get the chance @pipis2015 could you do a video of your sim with someone playing a game, it would give a much better idea of the end result of all your effort and hard work.
    • Like Like x 1
    • Agree Agree x 1
  13. pipis2015

    pipis2015 over-boost

    Joined:
    Feb 18, 2015
    Messages:
    222
    Location:
    Athens, GREECE
    Balance:
    10,244Coins
    Ratings:
    +253 / 1 / -0
    My Motion Simulator:
    2DOF, DC motor, Arduino
    Testing the simulator with max pwm(255) values and low tolerance(10-20) values (for maximum speed and maximum sensitivity/response) i ended up with some -expected- psu shutdowns.
    So...
    Latest addition(10 euro)...

    stby battery.jpg

    ... a standby UPS battery in parallel with the psu.
    It is cheaper and more compact than a big 12v capacitor.
    Its puspose is just to assist momentarily the psu.
    To be honest it is something that i expected so there was more than enough room to fit.

    But, boy what a difference in performance!!!
    • Like Like x 1
    • Informative Informative x 1
  14. RacingMat

    RacingMat Well-Known Member Gold Contributor

    Joined:
    Feb 22, 2013
    Messages:
    1,926
    Location:
    Marseille - FRANCE
    Balance:
    17,854Coins
    Ratings:
    +1,835 / 16 / -2
    My Motion Simulator:
    2DOF, DC motor, Arduino
    Good job!
    Yeah, at full max speed and short dead zone, the code pushes the smolka to a high level!

    Are your teeths okay?
    • Funny Funny x 1
  15. pipis2015

    pipis2015 over-boost

    Joined:
    Feb 18, 2015
    Messages:
    222
    Location:
    Athens, GREECE
    Balance:
    10,244Coins
    Ratings:
    +253 / 1 / -0
    My Motion Simulator:
    2DOF, DC motor, Arduino
    rumble-strip test
  16. Nick Moxley

    Nick Moxley Well-Known Member SimTools 2.0 Beta Tester

    Joined:
    Dec 13, 2013
    Messages:
    2,741
    Occupation:
    Owner/Operator- Moxleys Rantals
    Location:
    Winnipeg Manitoba Canada
    Balance:
    19,831Coins
    Ratings:
    +2,450 / 29 / -2
    My Motion Simulator:
    2DOF, 3DOF, DC motor, JRK
    Appears to be lacking a little travel/movement. what % are you running for the heave axis ?
  17. pipis2015

    pipis2015 over-boost

    Joined:
    Feb 18, 2015
    Messages:
    222
    Location:
    Athens, GREECE
    Balance:
    10,244Coins
    Ratings:
    +253 / 1 / -0
    My Motion Simulator:
    2DOF, DC motor, Arduino
    This was just an artificial test to show the finest oscillation that can be achieved.
  18. pipis2015

    pipis2015 over-boost

    Joined:
    Feb 18, 2015
    Messages:
    222
    Location:
    Athens, GREECE
    Balance:
    10,244Coins
    Ratings:
    +253 / 1 / -0
    My Motion Simulator:
    2DOF, DC motor, Arduino
    This is a test run @ nordschleife endurance with formula abarth(AC).
    Axis used are only sway and surge.
    • Like Like x 1
  19. pipis2015

    pipis2015 over-boost

    Joined:
    Feb 18, 2015
    Messages:
    222
    Location:
    Athens, GREECE
    Balance:
    10,244Coins
    Ratings:
    +253 / 1 / -0
    My Motion Simulator:
    2DOF, DC motor, Arduino
    With your suggestion in mind, i would like to ask this...
    What is the -lets say- suggested mechanical tilt/seat angle that is sufficient for a 2dof seat mover to provide "proper" experience.

    I am at: - 3,5 to +3,5 degrees at the moment for both front/back and left/right.
  20. Nick Moxley

    Nick Moxley Well-Known Member SimTools 2.0 Beta Tester

    Joined:
    Dec 13, 2013
    Messages:
    2,741
    Occupation:
    Owner/Operator- Moxleys Rantals
    Location:
    Winnipeg Manitoba Canada
    Balance:
    19,831Coins
    Ratings:
    +2,450 / 29 / -2
    My Motion Simulator:
    2DOF, 3DOF, DC motor, JRK
    That Abrath run looks like its supposed to, Minus a few of the forces of coarse. Why aren't you running Heave and Pitch or Roll ? FYI the heave is where the kerb osculation comes from.

    the degrees of movement all depend on YOUR particular setup, some want more movement some want less.