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Showroom No-Weld 2DOF Seat Mover On Homebrew Ricmotech RS1 Clone

Discussion in 'DIY Motion Simulator Projects' started by armpit, Jun 7, 2017.

  1. armpit

    armpit Active Member

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    Occupation:
    Software Engineer
    Location:
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    Balance:
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    My Motion Simulator:
    2DOF, DC motor, Arduino
    header.png

    Completed Jan 2018
    3.jpg
    2.jpg
    4.jpg



    IMG_20170916_121842 (1).jpg



    My Background

    I am a software engineer by career in my late 20's, an electronics hobbyist and I work occasionally on vintage motorcycles and do my own maintenance on cars so I hope to be decently competent with the mechanics of a build like this; but there will definitely be a lot of learning along the way.

    I have been documenting this build on facebook but have decided the users here would probably find it more interesting than my facebook friends.
    For my initial posting, I am going to split into a few individual posts that reflect the time passage between issues I had, so that it reads more like when it actually was happening.
    I started on May 5th 2017 and have been working a little every day on it.

    This build is still a WIP
    If you notice something I've done that is fundamentally wrong, please feel free to point it out; but if it's something minor then I'd like to learn my mistake on my own and come up with my own solution for it.

    Reason for the build
    I am renovating my mancave and decided that a motion simulator on a moderately cool looking platform would be a great addition to the aesthetics of the room and racing is my favorite thing to use VR for.

    Budget
    I initially set out to make a stationary rig for VR racing that I could modify into a 2dof seat mover, my budget was $300 USD (already had the seat) but that budget has inflated to $500.

    Constraints
    I do not own a welder and did not want to get one just for this project, so I am doing everything without any welds.
    The rig must be usable as stationary or motion
    Pinch-points must be left to a minimum, I have curious cats

    Now onto the build...
    I really liked the look of the Ricmotech RS1 cockpit, but I didn't want to spend $35 on the plans and have to wait for the template pieces to be shipped, so I mocked up my own design in sketchup that is a blatant rip-off of it, with an extended area behind the seat to fit the motors and electronics for when the seat mover is added.

    18121175_10208949562444836_8938208902963850540_o (1).jpg
    18077338_10208949563404860_715221334783391411_o.jpg


    After putting the plans together, I got to work with the woodworking

    18237741_10209042928458928_2876215172631352818_o (1).jpg

    And after 8 hours in the garage, here's what I had: (Drywall repairs are in the works since this project is part of a mancave renovation)

    18319364_10209051440991736_269403297209745640_o.jpg

    The joystick e-brake and shifter mounting are temporary so I can adjust their positions to what lines up naturally with where my hands go while in VR.
    At this point, the seat position is much too low, but this was by design since I will be adding a universal joint beneath it when I add motion.

    Parts list up to this point:
    Seat: Already owned
    Wheel/pedals/shifter/joystick: Already owned
    Nuts/bolts/washers/screws: $14
    Wood: $45
    Total: $59
    • Like Like x 4
    Last edited: Jan 10, 2018
  2. armpit

    armpit Active Member

    Joined:
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    Occupation:
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    My Motion Simulator:
    2DOF, DC motor, Arduino
    A lot of the essential parts are here.
    The wiper motor hubs came in (pic of one with and two without the hub), and I've been making progress on the arduino code portion (potentiometer feedback is working). I'm using the SMC3 code, it's really great and so much better than having to hand-roll code reinventing the wheel.

    Kill switch, heatsinks for the motor controllers, and heim joints on order, hoping to knock out the platform portion tomorrow evening.

    18451473_10209122926098819_1515297276347134420_o.jpg


    Wiper motor model: 14SW60-12V
    Sourced from ebay, OEM replacement for a volvo semi-truck wiper motor.
    Motor controllers are cheap Chinese clones of the standard VNH2SP30 chip motor driver (half of a moto monster shield)

    I bought 3 motor controllers and 3 motors so that I could have extra if something blew up or I needed parts.

    Wiper motors: $23/ea
    12mmID Motor Hubs: $21.50/ea
    Motor controllers: $1.50/ea (ebay special, we'll touch on this in a later post)
    Wiring: $18
    Fuse box: $7
    Arduino: Already owned
    Potentiometers: $10/10pc
    Universal Joint: $22/half

    Project running total: $254.50
    • Like Like x 2
  3. armpit

    armpit Active Member

    Joined:
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    My Motion Simulator:
    2DOF, DC motor, Arduino
    Testing the mounting for the universal joint. Determined that I'll need to elevate the platform in order to get the range of motion I'm after

    3.jpg

    Testing motor controllers with potentiometer feedback controlled by an arduino and PC software. Using a 250w power supply I had laying around. I quickly realized this would not be nearly enough juice.

    18451570_10209130423286244_6151055803448203470_o.jpg

    I was having issues getting the motor to run in reverse. When wired straight to +12v, it worked fine, same with -12v to run in reverse; but when I went through the motor controller, reverse ran at an absolute crawl and the chip would quickly overheat.
    This held true for the remaining 2 motor controllers. I refunded them all three as defective. and ordered another set from a different seller.
    • Like Like x 1
    Last edited: Jun 7, 2017
  4. armpit

    armpit Active Member

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    Occupation:
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    My Motion Simulator:
    2DOF, DC motor, Arduino
    Motor mount made for one side, I'll duplicate this later if I determine this does what I need. Cutting steel is a PAIN, probably overkill for this.

    18518397_10209137697708100_8586236147162360534_o.jpg

    With my hand-made motor arm attached

    18449751_10209137697788102_6057378925131561056_o.jpg


    Everything looked good so I duplicated it for the other side and mocked up the placement
    Heim joints showed up so I've got them laying around in these pics

    18556814_10209152319793643_1669294021214327574_o.jpg

    18588765_10209152319753642_7206663276046143658_o.jpg

    Steel and wood for the seat platform: $40
    Steel for motor mounts and arms: $15
    Heim joints: $7.50/ea including tapered spacers
    Misc bolts/washers/nuts: $10

    Project running total: $349.50
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  5. armpit

    armpit Active Member

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    Occupation:
    Software Engineer
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    My Motion Simulator:
    2DOF, DC motor, Arduino
    Mocked up how the motors will connect to the platform/seat in sketchup

    18527171_10209155219426132_4173415173224685312_o.jpg


    Got testing more on the electronics, this new motor controller also proved to be defective for one of the chips. The second chip worked fine so I was able to do a bit of testing; here's a video


    I've refunded this chip now and have an order from yet another seller that cost a little more that *fingers crossed* hopefully will be a good version.

    Came up with a way to have the potentiometers mounted so they can slip in the event of a runaway motor using vinyl hose connecting between the pot stem and a 6mm bolt I tapped into the back of the motor

    18739160_10209251287027762_5946797925562521284_o.jpg



    Mounted up the universal joint under the seat on a 2x4 platform. I will replace this platform with a 2x8 later down the road, probably when I take everything apart to sand and paint

    18768518_10209251286987761_127852595706823496_o.jpg


    Kill switch: $8
    Vinyl tube: $3

    Project running total: $360.50
    • Like Like x 3
    Last edited: Jun 7, 2017
  6. armpit

    armpit Active Member

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    My Motion Simulator:
    2DOF, DC motor, Arduino
    Drilled a hole in the motor arms and assembled it up with the heim joint

    18815107_10209251287067763_6493627119046762043_o.jpg

    18814596_10209251309228317_3142776043602594851_o.jpg

    Started on the mounting to connect the headrest of the seat to the base motion platform. I decided to use aluminum for this since I was sick and tired of cutting steel with a hacksaw and ruining jigsaw blades. I may end up having to replace these parts with steel, I have already noticed some minor flexing in testing....

    18766609_10209262036136483_3053152685914362642_o (1).jpg



    I also decided that I would use the factory plugs on the motors because they contain 5 wires, which happens to be the exact number of wires needed for +/- voltage to the motor and 3 wires to a potentiometer. I wired it back up and ordered the female adapters.

    18766708_10209262036096482_589288841622734960_o.jpg


    Aluminum and misc nuts/bolts/washers: $25


    Running project total: $385.50
    • Like Like x 2
  7. armpit

    armpit Active Member

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    My Motion Simulator:
    2DOF, DC motor, Arduino
    Linkages added and motors+mounts attached to the rig. It's starting to look like a real motion rig! Exciting stuff!

    18839872_10209270587190254_6832489797394387602_o.jpg
    18814780_10209270587030250_213442914168479545_o.jpg
    18814582_10209270587110252_7529958150560726567_o.jpg


    I used 1/2"-20 threaded rod for this, seems sturdy enough but if I notice flexing I will bolster it with some plumbing pipe.

    I also ended up adjusting the top mounting points inward a bit since I was getting binding down on the motor hubs when in extreme lean angles.



    Looks pretty dang close to the design, right??
    18921041_10209270630551338_1704898270842508181_o.jpg



    Threaded rods: $21
    Bolts/nuts/washers to mount motor mounts: $6

    Project running total: $412.50
    • Like Like x 6
  8. armpit

    armpit Active Member

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    My Motion Simulator:
    2DOF, DC motor, Arduino
    So while testing a single motor, I accidentally brushed the frame of the motion platform with +12v while the motor was connected to ground.... SPARK. This is when I realized that all the talk about "You must ground-isolate your wiper motors!!!!!" actually did apply to me as well. I thought I'd get around it by using a wooden frame, but completely negelected to think that having metal motor arms, rods, and a metal frame would all cause everything to be connected.

    I took a spare motor apart and stayed up until 5am learning how to do this, then for the real-deal it was pretty straight forward, just pulled a lead off of the overcurrent protection that was used as the case grounding point and soldered the brush straight to the "ground" wire, bypassing the case ground completely.


    overcurrent protection chip (I believe...) I disconnected circled in red, new direct connection circled in green
    18891824_10209284138209021_696157244105995856_o.jpg

    And the ground wire going straight into the casing

    18738874_10209284117168495_409459897515358276_o (1).jpg



    So I'm now ground-isolated and won't blow up my motor controller once I finally have a working one arrive!
    • Like Like x 2
    Last edited: Jun 7, 2017
  9. armpit

    armpit Active Member

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    My Motion Simulator:
    2DOF, DC motor, Arduino
    Put together a 'wiring harness' that will allow the motors and potentiometers to plug straight into the shield

    18815375_10209286359624555_6286838447563920468_o.jpg


    And now a blurry picture of one of my cats hanging out enjoying the chair while the room is an absolute mess testing out wiring, just for fun....

    IMG_20170606_235541.jpg


    Female plugs and clips: $15

    Project running total: $427.50

    So this is where I'm at, I'll continue to update real-time now that I've taken the plunge into posting here Looking forward to hearing what people are thinking of the progress so far. Thanks for reading!
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  10. armpit

    armpit Active Member

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    My Motion Simulator:
    2DOF, DC motor, Arduino
    Oh I do have one more thing I left out. Here is a quick video of me testing one motor hooked directly to 12v power



    I'm really happy with the range of motion I'm getting, I think I'll be dialing the side-to-side motion down a good bit.

    Why only one motor for the test?? Well, because the now 400w PC power supply I stripped down to use for this still can't provide enough power to start running both motors from a stop at the same time. I've ordered a 750w server power supply as recommended on various build threads, hopefully that will work much better for me!
    • Like Like x 3
  11. PiaMan

    PiaMan Active Member

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    My Motion Simulator:
    3DOF, DC motor, SCN5, Arduino
    Looks realky good. Just a note about cutting steel. My industrial supplier happily cuts stuff to order. Even on a $50 order so if you plan it out you can have your oeices cut for you. I can usually buy a 24' section for the same price as the hardware store 8' section
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  12. Nick Moxley

    Nick Moxley Well-Known Member SimTools 2.0 Beta Tester

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    My Motion Simulator:
    2DOF, 3DOF, DC motor, JRK
    How much "lean" do the Vertical arms have ? Whats the lever length your running ? And unfortunately that vertical tubing on the rear of the seat frame looks woefully under sized, and being aluminum those square section's dont have that much strength. When you sit in the rig, Video it from the rear and sides, im more than positive your going to see some major deflection which is very much unwanted.
    • Informative Informative x 1
  13. armpit

    armpit Active Member

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    My Motion Simulator:
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    I'll look into this, thanks for the advice

    In the photos, the vertical arms have no lean, but I have adjusted them inward about 4 inches on each side. I think I may need to revisit my motor mounting position and possibly go on the outside edges of the frame instead of the inside edges to get additional lean on them without having them connect too close to center at the top of the seat, but the heim joints limit me to 15 degrees of offset.

    The lever length is just under 2" to the center of the motor shaft. I think it may prove to be a bit too long for the power of these motors while I'm in the chair, but I'll find that out once I get the latest batch of motor controllers in and can test it with some weight in the seat.

    The rear tubing structure is not complete, I still have 2 connections to make to the top of the seat to support the horizontal rod that the rods from the motor arms connect to; but I think you're right, I need to bite the bullet and change over to steel. The aluminum is definitely flexing, I was hoping to rely on the internal structure of the seat to hold things together more than it appears to be.

    Thanks for the advice, going with what PiaMan said I'll be looking into additional steel tubing very soon to beef things up.
    Last edited: Jun 8, 2017
  14. armpit

    armpit Active Member

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    My Motion Simulator:
    2DOF, DC motor, Arduino
    Today I applied to get my DIY simtools 2.0 license, and my motor controllers' tracking shows they just left my local post office!
    Hoping that means they will be delivered today but their ETA shows tomorrow.

    I also reached out to a local steel shop and they have a minimum order of $40, so rather than getting 30 extra feet of tubing and having to figure out where to store it, I will be waiting to see how the aluminum holds up and getting another overpriced tube from Lowes if/when I notice any significant flexing.

    I'm having some friends over today to try out the rig as stationary, so I made a board insert that prevents the seat from pivoting while it's all still attached to the motors. I'll post a photo of this later today, just wanted to get a little status update up for now
  15. armpit

    armpit Active Member

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    My Motion Simulator:
    2DOF, DC motor, Arduino
    Here's the wooden insert that allows for a stationary rig. Nothing too fancy, I may add a hinge so it can fold away if I end up using it without motion more than just occasionally.


    IMG_20170612_232301.jpg
    IMG_20170612_232311.jpg


    Motor controllers came in a day early! But, as with everything seems to be with this build, there's a caveat: my wife is sick and I didn't have enough time to do any testing with it after soldering. Hopefully tomorrow I'm able to and they will test good!

    IMG_20170612_232458.jpg
    IMG_20170612_235041.jpg

    Still getting used to my soldering iron, it runs a bit hotter than I'm used to and the flux vaporizes pretty quick.
  16. Nick Moxley

    Nick Moxley Well-Known Member SimTools 2.0 Beta Tester

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    My Motion Simulator:
    2DOF, 3DOF, DC motor, JRK
    Yes a Tick on the hot side for the solder, But overall not too shabby. Keep at it. :cheers
    • Informative Informative x 1
  17. armpit

    armpit Active Member

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    My Motion Simulator:
    2DOF, DC motor, Arduino
    Big update today!

    I was able to test one of the motor controllers today, and it worked perfect! Finally!
    It came from ebay seller alice1101983, as recommended in multiple threads on this site. So relieved that I have a working motor controller, man that was frustrating!


    I modified the SMC3 code to use the pinout for the moto monster attached as a shield to the main arduino board, but there's a lot of voodoo magic going on in there that is preventing it from working plug-and-play with just swapping the output pins. I spent about half an hour trying to understand the complexities of the custom pwm functions but it's out of my scope of arduino knowledge for now so I just took it off and jumpered up one motor at a time for testing.


    I helped my brother move over the weekend and he gave me a CPU cooler he had laying around;
    IMG_20170613_205130.jpg

    I don't think I'll be using it, but if my northbridge heatsinks don't do the job at least I know I have the supplies available to overkill a cooling solution.
    IMG_20170614_005450.jpg


    I beefed up the horizontal rod that the "tie-rods" connect to by adding in the shoulder supports. This REALLY helped firm things up, and I'm back to feeling good about the seat itself providing a good bit of the whole structure's rigidity. I'm going to continue to stick with the existing aluminum portion until something fails, but it's not a significant concern anymore.

    IMG_20170613_201408.jpg

    I got my DIY license for simtools and started getting familiar with the software. This is when I discovered that my runaway motor solution for keeping the potentiometers from over-rotating works, but I also discovered that after a just a few over-rotations the vinyl tube gets chewed up on the inside and no longer maintains a good enough connection with the bolt tapped into the motor shaft to keep accuracy. I'm thinking I will use a small hose clamp to alleviate this issue.


    I also made a quick video testing out a single motor using the SMC3 utility.
    This is only running on 300w and trips any time I run both motors at once for more than just a few seconds, and sometimes even with rapid direction changes with just a single motor; the 750w server power supply should be here tomorrow to fix this. I'm not sure if the motors themselves can pull much more than they are, I'm a heavy guy and I sat in this while it was doing the 'motion' test and although it did move me around, it wasn't quite as rapid as I was hoping.
    I'll see how the new power supply helps, and if it still isn't where I want it I'll need to come up with some shorter motor arms to give it a torque advantage.
    Bonus: Cat appearance. She was riding in the seat for the test I did before recording, she wasn't sure how to react!

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  18. yobuddy

    yobuddy Well-Known Member Staff Member Moderator SimTools Developer SimAxe Beta Tester Gold Contributor SimTools 2.0 Beta Tester

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    Project is looking great man!
    Can't wait to see you ride it!
    yobuddy
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  19. nnamssorxela

    nnamssorxela New Member

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    Looking great.

    You mentioned going from 2x4 support for the seat to 2x8. Is this to prevent flex between the two "sides" of the U-joint? I would be inclined to replace or at least support the most stressed areas with metal once you get it working. Even just aluminum plate on each side of these critical points (U-joint and motor mounts) should prevent the bolts from digging into/wallowing out the wood over time and creating slop.

    I build a wooded pedal box and was surprised at how much it flexed. I suspect a chair will see significantly more force.
  20. armpit

    armpit Active Member

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    My Motion Simulator:
    2DOF, DC motor, Arduino
    The holes I drilled in the two 2x4's I used for the bottom support of the u-joint weren't perfectly straight and I didn't leave a gap between the wood. As I tightened the bolts up the two pieces of wood flexed into a small "V", so the single board is just to correct this bend.

    You can kind of see this in the last picture that I posted, the front board isn't flush with the base