_Gus's 6DOF Project

Hello! I've been working on this for a little while now, with much help from SilentChill, and from kind people on the discord.

Here's a list of the parts which I've purchased so far:

Motors - $1272.38
Motor Controller - $386.97
Arduinos - $56.37
PSUs - $145.29
Wood - $30.00
Glue & Screws - $28.43
Potentiometers - $117.92
Cables/Wiring - $79.15
Rod End (R) - $31.26
Rod End (L) - $31.26
18" Connecting Rod - $105.84
Wires - $35.00
Carriage bolt (5x5) - $30.00
Bolts and nuts - $24.00
VGA Cable - $8.71

total: $2382.58

----
Motors and gearboxes:


Motor shafts:


Sabertooth 2x32, PSU, and Arduino Uno


Wooden base:


Wooden cradle:

Cradle with the seat attached:


Base with the motors in place:


Now that I've gotten the parts that I need, and that I've assembled the bulk of the structure, I've begun working on the electronics portion of the project. I was very happy yesterday when I got my motors to move for the first time.

I've found someone very close to my location (not from this forum, a friend of a family friend) who has a garage filled with tools that have made everything a lot easier. Thanks to him, I've was able to create the pot mounts today using some fiberglass, tubing, and electrical tape. Given it takes almost no force to turn them, it should work fine.




That's about where I am right now. My plan right now is to work getting the motors and the pots all wired up to the Sabertooths, Arduinos, and PSUs, so that I can hopefully start testing everything with SimTools.

After that, I need to reinforce the parts of the cradle where I'm attaching the ball joints. I'm planning on using some 1/2" aluminum plate, putting in threads for 4 bolts, and a thread for the ball joint itself, and bolting one of these onto each of the joint locations to reinforce them.

I also need to somehow attach the levers to the motor shaft. I'm planning on cutting down and milling an aluminum shaft, so that I can run bolts into the small recesses in the motor shaft to attach it, and then bolting the crank itself onto the aluminum shaft.

Apologies if any of this is incoherent--it's about 1am right now, and I just wanted to get this posted tonight (this morning?). All advice and opinions would be appreciated. Feedback is how I improve.

Gus

What a nice surprise to see the same type of motor I was planning to use. I look forward to seeing project updates.

Something I ran across using a motor controller from cytron was pwm frequency whine. If you have any issues from the arduino side there is a helpful bit of code for the Nano to run pwm at 20khz online. Might take some playing around, but I think the timer they use has the same registry for the uno and mega.
https://forum.arduino.cc/index.php?topic=135847.0

I've wired up a pair of motors on my rig in the garage now (I'd previously only tested the motors inside on my Windows 10 PC), however I have an issue I'm hoping someone here could give me a hand with.

Wiring:


I don't want to move my Windows 10 PC to the garage, as I frequently use it inside for other things, and so right now I have a Linux box in the garage, and I'm using it with Wine so that I can run the .exe files I need to.

Unfortunately, I now seem to be unable to upload BlazingH's SMC3 Arduino code to my Arduino Uno. I'm having a dependency issue, despite having run the installer from Dimension Engineering for the Sabertooth/Arduino dependencies. I think the problem may be that their file is a .exe, and because I'm running it through Wine, it didn't work correctly. I really don't know though.

Error:

Any help in this regard would be greatly appreciated, as I'm not sure how to fix it, and would really like to avoid moving my Windows PC to the garage.

Thanks!
Gus

Thanks for the suggestion. I did this, and it appears to have worked, however I then effectively ran into the second part of your reply. Sadly, Wine does not play well with the serial ports, and so I was having a difficult time connecting to the Arduino. I've just given up and moved my computer out into the garage, which is working fine for now, however I've encountered a new problem.

It seems like the potentiometers are bouncing back and forth between min and max in their range (they're hall pots), and it's making the motor effectively just shake as it tries to instantly change direction. Here's a video of the issue, as well as of the SMC3 Utils output screen.



I'm just not sure what to do here. I thought the limits I set in the software would stop the motor from running to the edge of the pot, but I guess I was wrong. Also, I'm pretty confused as to why the motor would move in the opposite direction once it passes that threshold on the stop. Perhaps someone could give me a quick rundown on how the SMC3 Utils software works, because I couldn't figure this out from it's page.

"Too large a Ki can cause the position to overshoot and oscillate."

"PWMmin This is the minimum duty cycle that is used to drive the motors to their target position. For example if the motors are already close to target they will not need to be driven as hard as if they are a long way from target (or they may overshoot and oscillate)."

"PWMrev This is the PWM duty cycle that is used to drive the motors in reverse (hard brake) if they enter the limit zone ... Setting this to a similar value as PWMmax would make sense."

OK. I think I know what to do now. I'm not sure how I missed these portions of the post, but thanks for getting me to take another look. I think I had PWMrev set to zero, which is causing the motors to overshoot their limit, causing this oscilation issue with the pot. I also think that the motors are being driven reverse to what they should be, because they always move AWAY from the blue target line, versus moving towards it as I believe it should.

I'll get back with an update once I hopefully fix this. Thanks again!

Success! All the motors are now wires up, and everything seems to be working with SMC3. Thanks to Historiker who helped me out a lot.

Here's a pic now that everything is wired:

Got around to milling the aluminium reinforcements and mounting them to the cradle yesterday. I also swapped out the small 2x4 sections that attached each side of the cradle for plywood, as the 2x4s were being blocked by the heads of the bolts anyway, and the plywood should be sturdier anyway. Here are some pictures:

how many amps are your PSUs?

looking nice! keep going! 6DoF nation!

Here’s the link: https://www.ebay.com/itm/AC-DC-480-...hash=item2ac29424a8:m:mYcJbwrZl0npdg7NxWhjSqQ

It’s a 24v 20a psu

I'm having a really hard time trying to use SimTools—I've been trying to follow the tutorials posted here, but a lot of what I'm seeing is different, and there seem to be things that may be obvious to most people, but that I'm just missing and that the tutorials skip over. If there is anyone who may be around later who could hop in a discord or skype call with me to try and help me figure this out, that would be exceptional.

thanks for the link! i think a good video is this one

Thanks for the video, Hannibal! I momentarily got a motor to move using the axis testing feature of the SimTools Game Engine. Unfortunately, I am having quite a bit of trouble getting SMC3 to work, and to remember its settings.

Most times I run the SMC3 utility, it will proceed to freeze and then crash within a minute, and this happens especially often when I'm trying to set the "Out Mode" to "UDP Pass thru," which is what I believe SimTools needs it to be set to in order to work. This is happening on all 3 of my Arduinos, and so I doubt it is an issue solely based with them. Also, whenever I do manage to get the SMC3 utility output set to UDP Pass thru, when I restart the utility program, the out method is reset to "Monitor" every time. Does this mean I need SMC3 utility always running? Why won't the motors move when the utility is running, set to UDP Pass thru, and I use the axis tester in SimTools? I have so many questions, and I'm not sure what to do.

If you could give any advice on the problems I'm having that would be great.

Thanks!

Edit: I also want to mention that when I click "turn on" in the axis testing tab in SimTools, the program makes a beeping pattern. I'm not sure if this is normal or an indication of some issue.

i wish i can give u an answer. i only messed around with the utility for 2 days for pretest a few months ago.
but at this time i am still building my actuators.. im hoping i will start messing aroudn with power and SMC3.. ill probably be in your boat in a few weeks lol

Quick update: I've somehow managed to get axis 1 and 2 working (both connected to the same arduino), but I cannot get any other axes working. Has anyone encountered this issue before, or does anyone have any suggestions to get around it? All feedback is appreciated.

Also, whenever I restart the SimTools Game Engine, I get an error message saying that one of the arduinos (it says "device") connected to a comport cannot be detected.

Edit: I got a different arduino working after rebooting everything and plugging it all in again, but it seems I cannot get more than 2 motors functional at a time. It seems fairly random which one works.

Edit 2: Now two arduinos seem to be playing nicely with SimTools. I'm not sure what the problem is.

Edit 3: Now all of them are working after I swapped the USB ports the non-functional one was using with one of the functional one's port. Not sure what caused this, but it is fixed now (or so it seems atleast).

Just got back from Chicago yesterday, and was back at it again today. I finished making the cranks for the motors (no welding!) and I'm going to install them, and then hopefully attach the upper frame to the lower frame tomorrow after work. I'll give an update with a picture, but for now here are the cranks and a not-at-all-to-scale diagram:


The round pieces used to interface the crank with the motor shaft are stainless steel key hubs from OzRobotics, and were $20 each, with an additional $22 shipping for the 6 of them. While the pieces themselves seem fine, their customer service was terrible, they were late on their shipping, and also shipped from China, despite leading me to believe that it was a NY based company, so I'm not sure that I would recommend using them if you're looking to buy something similar. There are a bunch of similar items on AliExpress, which would probably do just as well and be cheaper. The only reason I went it Oz was because I thought the items would ship more quickly since they were supposed to be domestic.

Here's a link to the product on their website: https://ozrobotics.com/shop/14mm-stainless-steel-key-hub-18014/

Anyway, returning to my plan moving forward, my hope is to get the sim moving by the end of this week, and hopefully sooner. It's all going to depend on whether or not SimTools continues to work well with my motors since I was having so many issues before.

where you buy sabertooth you give me link sell sabertooth..?

It's assembled! Here's the pic:



I'm somewhat concerned about the strength of the connecting rods, but we'll see what happens.

Before I assembled everything, I finally reinforced the motor mounts with an extra block of wood below each one to make it a bit more rigid, as well as I attached the cranks to the motors (obviously). Here's some pictures of that stuff:

The sabertooth controllers are sold by Dimension Engineering. Here's a link to the page where I bought mine: https://www.dimensionengineering.com/products/sabertooth2x32