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.

_Gus's 6DOF Project

Discussion in 'DIY Motion Simulator Projects' started by _Gus, Jul 19, 2019.

Tags:
  1. _Gus

    _Gus Member Gold Contributor

    Joined:
    May 16, 2019
    Messages:
    50
    Balance:
    392Coins
    Ratings:
    +28 / 0 / -0
    I apologize if I’m just being stupid, but they should work fine, shouldn’t they? Brushless is more efficient, has a longer lifespan, and can still be controlled with the 2x32 board?
  2. SeatTime

    SeatTime Well-Known Member

    Joined:
    Dec 27, 2013
    Messages:
    2,290
    Location:
    Newcastle Australia
    Balance:
    26,826Coins
    Ratings:
    +2,582 / 29 / -0
    My Motion Simulator:
    DC motor, Motion platform, 6DOF
    No.
    • Like Like x 1
  3. _Gus

    _Gus Member Gold Contributor

    Joined:
    May 16, 2019
    Messages:
    50
    Balance:
    392Coins
    Ratings:
    +28 / 0 / -0
    Well shit. I guess it’s back to the drawing board.
  4. BM114

    BM114 New Member

    Joined:
    Jun 7, 2019
    Messages:
    26
    Balance:
    236Coins
    Ratings:
    +6 / 1 / -0
    Brushless requires a specialized driver. I believe it is driven via a trapezoidal waveform instead of a plain 'line's dc like a brushed motor is. Best of luck.
  5. _Gus

    _Gus Member Gold Contributor

    Joined:
    May 16, 2019
    Messages:
    50
    Balance:
    392Coins
    Ratings:
    +28 / 0 / -0
    SeatTime, thank you for catching this! I think that you've actually saved me ~$700, as I returned to look for a 600W brushed DC motor, and I've found a great deal. I contacted the seller of this motor, and while I've yet you receive the exact specs on the motor, they quoted me $115 for a motor/gearbox pair, which is less than half of what I was planning on spending on the brushless motors.
  6. BM114

    BM114 New Member

    Joined:
    Jun 7, 2019
    Messages:
    26
    Balance:
    236Coins
    Ratings:
    +6 / 1 / -0
    I noticed they do a 10 piece minimum. Are they going to give you the same price for only 6 motors?
  7. _Gus

    _Gus Member Gold Contributor

    Joined:
    May 16, 2019
    Messages:
    50
    Balance:
    392Coins
    Ratings:
    +28 / 0 / -0
    Yes. I’ve been chatting with the supplier and I asked for a “sample” of six motors, which they said would be fine. They will be the same price.
  8. BM114

    BM114 New Member

    Joined:
    Jun 7, 2019
    Messages:
    26
    Balance:
    236Coins
    Ratings:
    +6 / 1 / -0
    Sounds like a good deal. I noticed the motor specs 40A @24v which I assume is a peak of 960watt. Do you already have a power supply in mind?

    I look forward to seeing the progress. I may have to change to these motors myself if they are truly 700w.
  9. _Gus

    _Gus Member Gold Contributor

    Joined:
    May 16, 2019
    Messages:
    50
    Balance:
    392Coins
    Ratings:
    +28 / 0 / -0
    While that listing gives the specs for the 700w output motors (~80% efficiency), I contacted the seller and am going to purchase their 600w output motors, which have -750w input, so they’ll work with my current sabertooth controllers which saves me a lot.

    Beware though, while the motors are cheap, they are big! I was told for 6 motor/gearbox pairs it would be ~100kg, and so I’m going to be paying about $850 in shipping.
  10. BM114

    BM114 New Member

    Joined:
    Jun 7, 2019
    Messages:
    26
    Balance:
    236Coins
    Ratings:
    +6 / 1 / -0
    That would bring it to about $261 per motor?
    That's still pretty good.
  11. _Gus

    _Gus Member Gold Contributor

    Joined:
    May 16, 2019
    Messages:
    50
    Balance:
    392Coins
    Ratings:
    +28 / 0 / -0
    Quick update:

    I've ordered everything I planned to, and everything should be here in a couple of weeks (chinese motor company quoted me delivery in 3 weeks, but I don't have a tracking number yet). So far I've spent another $2400, and I expect to spend about another $150 on metal and wood.

    Because these motors will have about nine times as much torque as the current ones, I'm fairly sure that if I just bolted them into the current frame it would just rip it apart. To fix this, I'm going to pick up six 12"x8"x1/4" steel plates tomorrow so that I can make far stronger mounts for the motors. So that the lever arm doesn't hit the steel, I'm going to mill/cut out a rectangle for the lever arm and connecting rod to move through. This should greatly increase the area over which the motors are applying force to the bottom frame, and should also fix the minor movements I was seeing in the current wooden blocks the motors are mounted to.
    • Like Like x 1
  12. SeatTime

    SeatTime Well-Known Member

    Joined:
    Dec 27, 2013
    Messages:
    2,290
    Location:
    Newcastle Australia
    Balance:
    26,826Coins
    Ratings:
    +2,582 / 29 / -0
    My Motion Simulator:
    DC motor, Motion platform, 6DOF
    Often hard to know what the specs actually mean for a Chinese produced motor, hopefully the 40amp motors will not overload your sabertooths 2 x 32. Often specs can be a bit confusing, especially when the items are coming from China. As a example, images below are four motors that I testing out for my 6DOF many years ago (just initially purchased one of each). The larger one is a industrial grade motor rated at 200W and the three smaller ones are commercial grade motors rated at 350 W. Hope it all goes well for you.

    Actuator standard against bigger motor.jpg Actuator with motor_gearbox attached.jpg DSC02337.JPG New Motors.jpg
  13. _Gus

    _Gus Member Gold Contributor

    Joined:
    May 16, 2019
    Messages:
    50
    Balance:
    392Coins
    Ratings:
    +28 / 0 / -0
    The reason the motor there could be rated at 700w, is because the output is 700 watts, and the motor itself is somewhat inefficient, usually only 70-80% efficient, which means they need more than 700w to output 700w.

    Also, the motors I purchased have a 600w output, and an input of just under 750w (24v, 31.25a) which means they shouldn’t be able to overload my 2x32s.
  14. _Gus

    _Gus Member Gold Contributor

    Joined:
    May 16, 2019
    Messages:
    50
    Balance:
    392Coins
    Ratings:
    +28 / 0 / -0
    Just got my power supplies in the mail, and they seem to be good so far (no visible damage).

    IMG_5932.jpg

    There is a slight issue though, in that the wire I'm going to be using is extremely thick (4AWG), as it needs to handle 1500 watts (24 volts at about 60 amps), and the terminals on the PSU are not large enough to accomodate the connectors I bought, or even the wire itself.

    IMG_5932.jpg

    I'm going to look for wire-terminal connectors that will fit the PSU's terminals, however if anyone has encountered this issue before, any product suggestions would be greatly appreciated.
  15. _Gus

    _Gus Member Gold Contributor

    Joined:
    May 16, 2019
    Messages:
    50
    Balance:
    392Coins
    Ratings:
    +28 / 0 / -0
    Ok, so it turns out that when I was looking at how much current I could allow per wire gauge, I was looking at requirements for house wiring, which assumes a 100ft. cable. I'm only using 2 ft, so I just stepped down to 10 AWG wire, which means there will be about 3-4 watts dissipating into the wire on the way from the power supply to the sabertooth. This shouldn't cause any over-heating problems, and it also makes fitting the ring connector into the PSU terminal a whole lot easier, as with a little bit of time on the grinding wheel, I was able to coerce the ring connectors into the terminal slots.

    Here's an updated pic. I wired up the PSUs to AC, and the wires going to the sabertooths are on top, not yet connected.

    IMG_5940.jpg IMG_5941.jpg

    Apologies for grammar or spelling errors. It's late and I'm tired. Goodnight!
  16. _Gus

    _Gus Member Gold Contributor

    Joined:
    May 16, 2019
    Messages:
    50
    Balance:
    392Coins
    Ratings:
    +28 / 0 / -0
    I've decided to change up the design of my base quite significantly, and completely rebuild it. Instead of having the complicated structure of 2x4s, I decided to simply cut a 3/4" thick piece of plywood into a hexagon, and build a foot for it out of 2x6s. This gives me the lateral stability I need for the motors and also looks a lot cleaner.

    On top of the new base, I'm placing six 1/4" thick steel plates, which I've milled to have the correct hole placement for mounting the motors to. I'm running a bolt through the holes in the motor's gearbox, through the plate, and through the plywood, so everything will be super solid, and I also will avoid having to fasten the plates to the plywood separately.

    I haven't yet mounted the motors to the base yet, as I'm planning on cleaning up all of my electronics and making it all look a bit nicer. I know that once I hook everything up and get it working, I'll never want to come back and change anything, so I figure it's better to do it now and get it out of the way. My plan for this is to just drill directly into the plywood, and probably use some zip ties to get everything in place.

    Here's the new base, with the steel plates on it:
    IMG_5964.jpg

    It's exciting getting all of this stuff done, but unfortunately, the new motors I ordered have still not been shipped from the factory in China, and so it's still going to be quite a while before I can actually ride on this thing :(.
  17. _Gus

    _Gus Member Gold Contributor

    Joined:
    May 16, 2019
    Messages:
    50
    Balance:
    392Coins
    Ratings:
    +28 / 0 / -0
    I haven't posted an update in a while, but the motors finally came this week, and I had a chance to mount them on the new base. Here's a picture:

    frame with new motors.jpg

    Unfortunately, these motors arrived without output shafts for the gearboxes, and so I had to order those from China as well. It's going to be about a week before they arrive, and until then I'm going to hold off on making the potentiometer mounts, as I need to be able to test the connection with the shaft before I make all 6 of them.

    I bought the key hubs for the shafts already though, as I know the diameter, and so I'm going to be making the crank arms this weekend out of the 3/8" steel and some 3/4" steel. The thicker steel is going to be tapped and bolted to the 3/8" to serve as a spacer.
    • Like Like x 1
  18. Historiker

    Historiker Dramamine Adict Staff Member Moderator Gold Contributor

    Joined:
    Dec 16, 2010
    Messages:
    1,872
    Occupation:
    Teacher/Cabinet Maker
    Location:
    Michigan USA
    Balance:
    9,549Coins
    Ratings:
    +1,755 / 12 / -1
    My Motion Simulator:
    DC motor, Arduino, Motion platform, 6DOF
    Way way off topic: What pedals are you using on your Marin? They look like they have oversize bearings and comfortable platforms.
  19. _Gus

    _Gus Member Gold Contributor

    Joined:
    May 16, 2019
    Messages:
    50
    Balance:
    392Coins
    Ratings:
    +28 / 0 / -0
    To be honest, I have no idea. It's whatever came stock with the bike, and recently they've actually both lost all structural integrity, and so you're just kind of pushing on the rod that goes through them. I've been meaning to get it fixed.
  20. Historiker

    Historiker Dramamine Adict Staff Member Moderator Gold Contributor

    Joined:
    Dec 16, 2010
    Messages:
    1,872
    Occupation:
    Teacher/Cabinet Maker
    Location:
    Michigan USA
    Balance:
    9,549Coins
    Ratings:
    +1,755 / 12 / -1
    My Motion Simulator:
    DC motor, Arduino, Motion platform, 6DOF
    Sorry to hear that. I am never satisfied with my pedals, course I abuse them so I cannot fault the brands that I have used. I am a really big guy and in my head I can hear my pedals cry when I get ready to ride. The language that my saddle uses is not fit to repeat anywhere. :grin

    Back on topic : your build looks good so far, hope the shafts arrive soon to see more.