Most of the robot arms we see are cool but little more than toys. Usually, they use RC servos to do motion and that’s great for making some basic motion, but if you want something more industrial and capable, check out [Pavel’s] RR1 — Real Robot One. The beefy arm has six degrees of freedom powered by stepper motors and custom planetary gearboxes. Each joint has an encoder for precise position feedback. The first prototype is already working, as you can see in the video below. Version two is forthcoming.
When you see the thing in action, you can immediately tell it isn’t a toy. There are four NEMA23 steppers and three smaller NEMA17 motors. While there are 3D printed parts, you can see a lot of metal in the build, also. You can see a video of the arm lifting up a 1 kilogram barbell and picking up a refreshing soft drink.
From [Pavel’s] comments about the second revision, it sounds like he is trying to minimize backlash which must be a bit of a problem with the first version. One thing we didn’t see were any design files for any part of the device so, for now, it will just have to serve as inspiration. But since the project is up on Hackaday.io, we are hopeful we will eventually get a peek at the second revision design.
Meanwhile, if you want to build something more modest, maybe raid a CD drive. While servo-based arms have a bad reputation, you can, in fact, make them very capable with some work.
Well, I don’t know much about robot building (yet, HAD helping) but I do visit auction sites and was a little frustrated having to go through three or four 60-item pages of steppers. So, it you are looking for cheap steppers you might want to check out
https://www.bidspotter.com/en-us/auction-catalogues/bscequipment/catalogue-id-equipm4-10015
Ends 8/11. Not sure what the shipping/removal policy is. Be care of the rigging fees.
What is a rigging fee?
After you win your auction and pay, removal occurs. The auctioneers may hire help to move lots in an orderly manner. So rather than you going into the warehouse (or whatever) and grabbing your lot, you pay, over and above your winning bid (and buyers premium and applicable taxes), to have your item brought to you. I’m guessing that much waiting, by you, also occurs.
May include wrapping, strapping to a pallet, loading onto your vehicle, etc. I’m guessing for a stepper motor that fits in your hand they walk in, grab a cup of coffee, drink it, then find your item, maybe another cup of coffee, and finally bring it to you. Box for item is an additional fee.
When I was 15 I attempted to bid $1 on a _giant_ worn out milling machine that would have gone 5+ boxcars disassembled.
They wouldn’t take my bid.
I was sure I could have gotten it out of there in a weekend with two friends, a cherry picker and a pickup truck. My plan for the bid was scrap metal sales. Keep the good bits. Was clueless as a 15 year old.
I did get a decent scope for $20, no probes.
Riggers are industrial machine movers. They ain’t cheap, some are skilled, others hacks. YMWV
What if I arm wrestle with that robot? Can you burn a servo motor? Or does my arm disintegrate into multiple pieces?
It looks like stepper motors and gears (probably 3d printed) so I think you’re more likely to wear out the gears or cause the steppers to skip
cool stuff, you could probably use a machine like this to play chess games with multiple opponents!
great arm but it seems painfully slow.
RC servos aren’t great, but neither are stepper motors.
If the motors don’t have tachometers and position feedback (or functional equivalent), it’s hobby grade robotics. Also ball screws!
Ballscrews are very rare in industrial articulated robots. Gantries, sure, but for articulated robots you’re looking at geared servos and, once they get big, pneumatic counterbalances.