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PAROL6 Desktop Robot Arm

github.com

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Re: PAROL6 Desktop Robot Arm

#41

Post by krasin »

iancmceachern wrote: post #37
krasin wrote: post #34

Earlier quoted context omitted.

> 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.

Just print it and find out. If there is a problem put in heat set threaded inserts. I don't think it'll be a problem though

> If there is a problem put in heat set threaded inserts

You would be surprised how many screws will go lose after a a thousand of hours of operation, even in this case.

Re: PAROL6 Desktop Robot Arm

#42

Post by iancmceachern »

krasin wrote: post #41
iancmceachern wrote: post #37

Earlier quoted context omitted.

Just print it and find out. If there is a problem put in heat set threaded inserts. I don't think it'll be a problem though

> If there is a problem put in heat set threaded inserts You would be surprised how many screws will go lose after a a thousand of hours of operation, even in this case.

I'm a mechanical engineer, product designer and technical leader that has designed many products, some of which have been implanted in people and are in the Smithsonian, etc. I know screws can come out, that's why they make loctite.

What I'm saying to you is to make sure something is an actual problem before saying it is. In this case, the fact that the screws are used as self tapping, the screws themselves create the threads, likely combats this. Like a nylock nut.

This isn't what I would do for say, a surgical robotics system, but that's not what this is.

If given the choice of having the design as is, or making it more expensive, more difficult to assemble, and less accessible. I'd choose it as it is.

There are always tradeoffs. I believe the designer made the right ones here.

Before saying they didn't, maybe build one.

Re: PAROL6 Desktop Robot Arm

#43

Post by krasin »

iancmceachern wrote: post #42
krasin wrote: post #41

Earlier quoted context omitted.

> If there is a problem put in heat set threaded inserts You would be surprised how many screws will go lose after a a thousand of hours of operation, even in this case.

I'm a mechanical engineer, product designer and technical leader that has designed many products, some of which have been implanted in people and are in the Smithsonian, etc. I know screws can come out, that's why they make loctite. What I'm saying to you is to make sure something is an actual problem before saying it is. In this case, the fact that the screws are used as self tapping, the screws themselves create th…

This is a case, where appeal to authority actually makes sense. Thanks, I accept your point.

Re: PAROL6 Desktop Robot Arm

#44

Post by Cilvic »

nulld3v wrote: post #6
sgnelson wrote: post #5

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 compariso…

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.

Does someone know how much this amounts to roughly?

Re: PAROL6 Desktop Robot Arm

#45

Post by mohn »

iancmceachern wrote: post #39
bitwize wrote: post #10

Sweet! An Armatron for adults!

I love the armatron. It was so many engineers first exposure to robotic systems, was affordable and get-able by regular people, and magically ran off on one single motor. I was just watching some YouTube videos on it and how well designed the mechanics of it are, so clever!

I was researching the Armatron last weekend and was surprised to learn then about the single-motor operation. It's quite a complex system of linkages and transmissions [0] to enable the six degrees of freedom. I suppose that explains why the toy is so noisy. I had no idea that was how it worked, must not have taken mine apart when it broke or I outgrew it or whatever happened.

[0] http://www.jeff-z.com/pinball/toys/armatron/armatron.html

Re: PAROL6 Desktop Robot Arm

#46

Post by iancmceachern »

mohn wrote: post #45
iancmceachern wrote: post #39

Earlier quoted context omitted.

I love the armatron. It was so many engineers first exposure to robotic systems, was affordable and get-able by regular people, and magically ran off on one single motor. I was just watching some YouTube videos on it and how well designed the mechanics of it are, so clever!

I was researching the Armatron last weekend and was surprised to learn then about the single-motor operation. It's quite a complex system of linkages and transmissions [0] to enable the six degrees of freedom. I suppose that explains why the toy is so noisy. I had no idea that was how it worked, must not have taken mine apart when it broke or I outgrew it or whatever happened. [0] http://www.jeff-z.com/pinball/toys/a…

Totally.

It also highlights an interesting change in engineering and product development that has happoned in my lifetime.

It used to be, when this Armatron was made, electronics and computers were magic and mechanical engineering, real complicated kind of mechanical stuff, was common and the slillset to do it was similarly common. In that world it makes sense to have the whole robot arm powered by one motor that constantly spins, with mechanical clutches and linkages deciding what moves when. That's because electronics and mechatronics like motors and encoders were still expensive and new.

Now its the opposite. In general, if given the choice between a complicated mechanical solution and a "simple" electronic/computer solution we choose that. Simple is in quoted because modern electronics and computers are far from simple. The manufacturing of a modern semiconductor rivals the Manhattan project. But is seems simple because we can just buy it at best buy and program it to do things. You can easily find lots of engineers to do something with code or an arduino, but finding someone who can design a fly ball governer, or even know what that is and why it matters, is rare.

Now days there are tons of cheap robot arms that have a servo motor for each joint, because servos are cheap and complex mechanics are not.

Re: PAROL6 Desktop Robot Arm

#47

Post by Vespasian »

PCrnjak wrote: post #33
Vespasian wrote: post #4

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.

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…

Sounds very interesting.

Maybe this is a project where I can put the random collection of components to use which lying around in my basement.

Not exactly to spec but that's the spirit I think.

Re: PAROL6 Desktop Robot Arm

#49

Post by Svenstaro »

hobofan wrote: post #21

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

Are you maintaining that list?

Re: PAROL6 Desktop Robot Arm

#50

Post by chillbill »

PCrnjak wrote: post #48
iancmceachern wrote: post #38

Earlier quoted context omitted.

Welcome to the future

PAROL6 creator here. I believe you dont usually need google account for forms. I messed it up when I was creating it :P

It’s still required, in case you want to switch that toggle off…
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