Oct 15, 2018

Misc noob questions ;)


Noob questions warning. I want to make a welding robot arm for our family company and I've been looking for inspiration. I found your video and github page, and it's just pure GOLD. Thanks for all this. I'l be buying the CADs at the very least.


1) Do you think this robot will be enough for welding?

2) I want to teach it its moves by example. I don't know how exactly I'll be doing it, but maybe the simplest method would be making a second identical arm with encoders instead of motors. Or use a SpaceMouse as a force control for teaching. I don't know yet. I'll figure things out in due time, after I first played with the robot as it is. But in general, do you think it's feasible? (I have no idea about any of this yet, but I'm generally quite good with computers, technology, and figuring things out)

3) Aren't servos better than stepper motors (something about losing steps and knowing current position)? If I wanted to use servos, would it be possible without major changes?


Thanks again for making this project!


Oct 15, 2018

Its certainly possible however I would be concerned with size - not knowing your application; it is a small desktop robot. Another thing to consider is speed. The AR2 is driven in motor steps and speed is a calculation of max percent. With trial and error you could create a repeatable process however it wouldn't be something you could calculate exact mm per sec up front. The robot is run via serial commands through a low cost arduino so there is a pause between movements that could prove problematic for running a spline movement - I am currently working on program updates to eliminate pause between moves as well as linear and arc interpolation, also working on robot control via wireless playstation controller so stay tuned on that. Servos would be ideal - the primary goal was the lowest cost robot possible that was still profesional/usable. The current software is designed around stepper motor steps so incorporating servos would not be easy with the current configuration but my next goal will be a larger closed loop robot that uses absolute encoders for position feedback - and as low cost as possible that people can make themselves and stay open source.

Oct 17, 2018

Hi Chris,


If you were to make a large version of your robot what motors would you suggest? And do you have thoughts/opinions on the Teknic ClearPath motors? (https://www.teknic.com/)


P.S. The Aluminium frame is on the way. Thank you!

Oct 18, 2018

@paul Ive looked at teknic before and they look like an interesting option. Looks like it might get expensive though. Im not sure yet what motor I will go with. im looking into some brushless DC options as well as sticking with standard steppers with encoder feedback. I really want to keep the price down but im not sure yet.

Nov 2, 2018

Ok, so I think the robot might be enough for us. The most important thing is having a ready made mechanical design and having all hardware decisions made for me. And having a working software from you I also think I'd be able to tinker with it and make it to exactly suit our needs.


Anyway, could you give any time frame for development of the third robot? How long do you think it my take for you to publish it? If it's not that long then maybe it doesn't make sense for us to build the current one, especially that unfortunately it is indeed just barely big enough for us. Or maybe you already have a part list and CADs for the new robot that you can sell? And we'd worry about the software later ;) I'd just like to know the overview of the situation before I commit myself to a decision, one way or another ;)

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