[HN Gopher] PAROL6 Desktop Robot Arm
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PAROL6 Desktop Robot Arm
Author : tildef
Score : 122 points
Date : 2023-09-09 14:37 UTC (8 hours ago)
(HTM) web link (github.com)
(TXT) w3m dump (github.com)
| hobofan wrote:
| I tried to collect a rough overview of available robot arms a few
| years ago (with focus on low-cost/open-source ones).[0]
|
| If anyone has some pointers on other recent projects in the
| space, I'd love to hear about them!
|
| [0]: https://github.com/hobofan/collected-robotic-arms
| sgnelson wrote:
| I wonder how this compares to the AR4 robotic arm (
| https://www.anninrobotics.com ). The AR4 isn't truly hardware
| open source, but my understanding is that it's software agnostic.
|
| My biggest question is the full cost for the PAROL6. Their BOM
| link is 404.
|
| I can build the AR4 completely for less than $2000, and for
| education, that's a very small price for a semi-useful, full 6
| axis arm. (Currently, to give a comparison, one of my suppliers
| is offering an educational cobot solution for $40,000. Yes, it's
| truly "industrial," and is a complete self-contained solution,
| though it's only capable of 2kg if I recall correctly. This was
| what they were pushing for the educational market.)
|
| As someone who is trying to implement robotic training in
| education, with a budget that approaches zero, I just need
| something cheap that students can hack/break/fix without costing
| a fortune in maintenance costs.
|
| One of the cool thing about the AR4 is that it can come as a
| complete kit, either as 3d printable or aluminum frame. and they
| work with Steppers Online to provide the steppers and drivers as
| one package. If you work for a school system, this type of
| solution solves a lot of logistical issues.
|
| That said, if this thing is truly low cost, let's say under
| $1000, for it's capabilities, it could be a very nice project.
| nulld3v wrote:
| The BOM file is in the repo I think:
| https://github.com/PCrnjak/PAROL6-Desktop-robot-arm/blob/mai...
|
| Looks like they forgot to update the link.
| wigiv wrote:
| Seems like an open-source/DIY or kit (requiring some assembly)
| for educational applications is great in the context of a class
| or project where building/fixing/upgrading the robot is the
| point, and where 3D printing is readily available.
|
| If the main purpose is for the robot to _do something_ - the
| DIY approach is more likely to suffer issues that, without
| support, may discourage students because they 're fussing
| with/fixing the bot instead of doing the thing.
|
| Out of curiosity, what's the $40k kit you mentioned?
|
| Educational packages are all over the place (some seem to be
| price-gouging, frankly) but the low-end (in terms of payload +
| reach) of commercial/industrial cobots is getting pretty
| affordable.
| sgnelson wrote:
| You're completely right about the DIY vs. Industrial issue.
| And the reality is that I need both, a DIY solution to teach
| students "this is how they work, these are the fundamentals,
| this is how to fix them/change them/operate them." And I also
| need one that can be hooked up to other machines, and able to
| be a true industrial robot (not so much with weight capacity,
| but with reach), and be a true integrated system to show
| students: "That other one was a toy, now here's how to use a
| real one in industry."
|
| But I basically now operate in Bureaucratic Hell, and I have
| to figure out a way to get the equipment to teach my
| students. And due to changes in how my organization operates,
| ironically enough, I've found that getting the
| "professional/educational/industrial" products is often not
| the right decision.
|
| One of the worst things that can happen is that we buy a
| $250,000 piece of equipment. The administration will never
| ever budget for the cost of maintenance, consumables,
| tooling, training, everything else required to successfully
| operate it. Within a year, you're stuck with a $250,000 piece
| of equipment sitting in a corner collecting dust, that is
| always shown to VIP's on tours as the latest in greatest in
| what we offer. Oh, and it's so expensive, we're not going to
| allow students to use it anyway, because we can't let them
| break it.
|
| And it's amazing, they won't have funding for that $100 tool
| I need to teach the students and use everyday, but every year
| they'll manage to find $100,000 to spend, a week before the
| end of the fiscal year, which we have to spend immediately,
| but it can only be spent on certain items, like the things
| that I don't actually need. Welcome to public technical
| education in America. (Sorry, obviously, you unintentionally
| touched a nerve.)
|
| But if I can get something that costs $2000, well, I can
| either fix it myself, or better yet have the students do it I
| will take something that I know is sustainable, that students
| can actually put their hands on and operate over that white
| elephant every day of the week.
|
| In reality, this is all moot. No matter the cost, my budget
| is effectively zero at the moment. But I can hope.
|
| The $40k was a Universal Robots UR3e I believe. The vendor
| put it on a cart as a portable, self-contained system.
| PCrnjak wrote:
| That is basically why made this robot. During my high
| school days we were 30 students on ONE old mitsubishi robot
| that was pain to program and was dangerous. On collages it
| was "oh we have 2 40000 euro robots but they are too
| expensive for students". So in both world we were mostly on
| simulators and simulators suck. I started with faze4 robot
| that was financed by my college but it was too large robot
| and i did not write any good software for it. More
| impressive thing than mechanical part or PAROL6 is its
| software and GUI. It is made for easy programming, has
| build in scripting language, jog control, error logging...
| Also i plan to port all my robots to that software and in
| the future make it universal for any robot. So you get a
| PCB that can communicate with the PAROL6 software,
| configure your robot kinematics and you are up and running.
| monkmartinez wrote:
| Here is the link to the most recent BOM:
| https://github.com/PCrnjak/PAROL6-Desktop-robot-arm/blob/mai...
| Arcanum-XIII wrote:
| I'm curious, what kind of project could you do once you built
| it ?
|
| My major issue is that I can easily build stuff. The puzzle
| keep my brain on the job - but then I don't know what to do
| after I've checked it works :D (i.e my various RC project are
| there, but then what ? I've built a rover, can do some
| automated stuff, but not very useful a the end...)
| RobotToaster wrote:
| >The AR4 isn't truly hardware open source
|
| Being pedantic this isn't either, there's no CAD source files,
| only stl files. Hopefully that's just an oversight.
| qingcharles wrote:
| For someone that hasn't used a CAD package in 30 years, can
| you explain the importance of this for me? Is a STL like a
| JPG is to a RAW in a camera?
| namibj wrote:
| Freeware vs. Open-Source. PNG vs. SVG.
| RobotToaster wrote:
| An STL is just a mesh, a collection of joined up points.
| It's like exporting a JPEG of a word document, you can
| print it but editing is a huge pain. For instance STLs
| don't support curves, so they're approximated with lots of
| short lines.
|
| Usually CAD interchange is either in STEP or the program's
| proprietary format.
| abraae wrote:
| More like source code vs object code in a compiled computer
| program.
| sterlind wrote:
| STL is to CAD as JPG is to SVG basically.
| LegitShady wrote:
| The STL is a mesh file that is used to generate g-code that
| a 3d printer or CNC machine understands.
|
| The CAD file, whichever format its in, is going to have all
| the solid modelling information and be much more useful if
| you want to make changes.
| hadlock wrote:
| You would expect STEP files in an open source project. This
| allows you to change the motor interface to use locally
| available stepper motors, adapters, or other modifications.
| STL is an intermediary, "rendered" 3D STEP file, ready for
| conversion into final custom gcode assembled specifically
| for your machine and any accessories/user specific
| procedural steps/initiation procedure etc.
|
| STEP is the sheet music, MP3 is the STL and the waveform is
| the gcode.
| [deleted]
| bitwize wrote:
| Sweet! An Armatron for adults!
| PCrnjak wrote:
| Hi guys I am the creator of PAROL6 arm. I was not aware of this
| community so if you have any questions feel free to ask me here.
| Also new video is up explaining more things.
| https://www.youtube.com/watch?v=PiBCbHtvbpE&ab_channel=Sourc...
| Also anyone interested in building/buying it can sign up on these
| 2 forms for more updates.
|
| You can sign up here for beta testers (there are a few spots
| left: https://forms.gle/sZqHVLPoMJxuVAyJ9 This is general form
| for people interested in control boards, kits, or whole robots:
| https://forms.gle/XkSvStwnQxw1f8xL8
| barkingcat wrote:
| Cool I'll try to build one.
| Animats wrote:
| There are lots of low-end robot arms. I have a uArm, which is not
| very good, on my desk. Way too much slop. Repeatability maybe
| 2mm.
| ilaksh wrote:
| The instructions detail everything including the exact
| screws/nuts needed. EXCEPT the most important parts, the actual
| motors! It doesn't give any specs or names or a thing for those.
| Incredible.
|
| Also the BOM info is gone.
| unwind wrote:
| Another poster mentioned the BOM link, it's 6 NEMA 17s of
| various torque ratings.
| PCrnjak wrote:
| Hi i am creator of PAROL6, the BOM link is fixed. Also about
| the bom it will soon be updated in more detail. My focus is
| now more on software and finishing touches on hardware to
| make it safe so some changes happen in BOM. That is why is
| seems "incomplete or rough"
| janci wrote:
| I would love having one capable of unloading the dishwasher.
| NavinF wrote:
| I've thought about building a robot to do that, but I think it
| would be cheaper to buy 2 or 3 dishwashers and modify them for
| use as cupboards. One will always be open for loading dirty
| stuff and another will always be open for retrieving clean
| stuff.
|
| btw ultrasonic cleaners are like miniature dishwashers and
| having one near my office room is very convenient for cleaning
| hardware compared to using the full-size dishwasher in the
| kitchen. Only disadvantage is that it needs soundproofing
| Vespasian wrote:
| Interesting project.
|
| I wonder how the rigidity holds up over time. Working at a
| robotics company, the mechanical engineers had to overcome quite
| some challenges to find a compromise between, precision, speed
| and repeatability.
|
| And that was with a metal frame.
| krasin wrote:
| My biggest concern is that they use screws over plastic as
| fasteners: https://github.com/PCrnjak/PAROL6-Desktop-robot-
| arm/blob/mai...
|
| Quote from the manual:
|
| > Screws are in this example M3 screws and holes are undersized
| to 2.7-2.8mm that means that when we screw in the screws we are
| tapping holes in 3D printed parts.
|
| > There are multiple benefits to this:
|
| > * Connection is strongest compared to tapping holes with a
| tap or using brass inserts
|
| > * It is simple and fast
|
| > * No need to prepare the hole, it can be printed undersized
|
| > Cons are that you can't disassemble it a lot of times. In
| case you feel screws slipping in the hole. Put some super glue
| in the hole and wait for it to cure. After that re tap the
| hole.
| invalidator wrote:
| I've used this technique on several of my projects. The
| formed threads are strong and reliable. It cuts down assembly
| steps and BOM. The tight fit means the screws won't back out
| (like locktite or nylocks). The only downside is they can
| only be reassembled a few times before they start getting
| loose, at which point you can either add material
| (superglue), or just reprint the part.
|
| If you have something you want to reassemble frequently, use
| inserts. If you're putting it together once and intend to use
| it that way for a long time, threadforming works fine.
| krasin wrote:
| > I've used this technique on several of my projects.
|
| Did they have any moving parts? Did they experience
| continuous vibrations and frequent mechanical shocks? For
| DIY robot arms, fasteners are very often the issue #1, if
| arms operated more than just for demo purposes.
| sgnelson wrote:
| I imagine a lot of that will have to do with the 3d printed
| material used. If you're talking typical FDM style PLA, ABS,
| the creep on these can be pretty terrible.
|
| If you're talking something like carbon fiber reinforced nylon,
| it's probably a bit better. If you move to something like
| Markforged's fiber-strand reinforcement it'd get even better.
| And then there are the SLA/SLS solutions, like Formlabs "rigid"
| material, which I think would be a very interesting material to
| try for this.
|
| I think at the end of the day, you need to keep in mind this is
| an educational robot, not an industrial robot. If it can
| maintain 0.050" of repeatability, that would probably be good
| enough for a lot of use cases (but of course, that depends on
| your use case.)
| PCrnjak wrote:
| I have been abusing it for 8 months straight and too be honest
| I was trying to break it. Software has a lot of safety features
| to not hit joint limits, speed limits, ESTOP is operational...
| Only problem is that robot has no brakes so during power loss
| it falls. I thought it will be fatal for robot to fall like
| that but it survived it multiple times. Only parts that brake
| are esthetics and covers. Also i thought that repetability will
| suffer under such abuse but it stayed the same. The clip on
| youtube is after 6 months of a lot of use.
| krasin wrote:
| The video of the robot arm in action:
| https://www.youtube.com/watch?v=PiBCbHtvbpE
|
| Very impressive repeatability and very smooth movement for a 3d
| printed arm.
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