Hackaday Prize Semifinalist: An Affordable Robotic Arm

Industrial robot arms are curious devices, found everywhere from the back of old engineering classrooms where they taught kinematics in the 90s, to the factory floor where they do the same thing over and over again while contemplating their existence. For his Hackaday Prize entry, [Dan] is building a big robot arm. It’s not big enough to ride on, but it is large enough to automate a few processes in a reasonably well-equipped lab.

This is not a tiny robotic arm powered by 9 gram hobby servos. For the bicep and tricep of [Dan]’s arm, he’s using linear actuators – they’re high precision and powerful. A few months ago, [Dan] tried to design a hypocycloid gear but couldn’t get a $3000 prototype to work. Although the hypocycloid is out, he did manage to build a strange differential pan/roll mechanism for the wrist of the arm. It really is a thing of beauty, and with the engineering [Dan] has put into it, it’s a very useful tool.

If you’d like to meet [Dan]’s robot arm in person, he’ll be at the 2015 NYC Maker Faire this weekend. Check out [Dan]’s Hackaday Prize video for his robot arm below.

The 2015 Hackaday Prize is sponsored by:

24 thoughts on “Hackaday Prize Semifinalist: An Affordable Robotic Arm

  1. Okay, usually I just troll and make explosive comments but this arm is pretty cool
    I say the because it is not 6″ tall and powered by $3 tower pro servos. And really I think it could be used to actually do something.
    Kudos to the creator.

        1. Cheap linear actuator = car electric window mechanism. Also, electric seat movers have serious grunt but likely will cost more unless you get lucky and score some ruined upholstery with good motors attached.

      1. I use those same actuators (or ones that look to be exactly the same) in test rigs at work, and they cost about $50 each when you buy them singly. The vendor does have a discount with quantity but I don’t remember exactly what that is – perhaps 5 or 10% off.

        And yes, they are tremendously powerful.

        1. I think they would most likely be these (link). I just ordered some for work (who wants to use hydraulics anyway?). They have a built-in linear pot so they can be controlled almost as easily as a servo. Sadly the speed and strength are a tradeoff, so you can get ones that move at 50mm per second and lift 5KG or ones that move at 10mm/s and can lift 200KG. I wish they were cheaper, then I’d use them in heaps of projects, but at $65 each it’s not a cheap part.

          http://www.aliexpress.com/item/250-mm-10-inches-stroke-750N-Load-12VDC-linear-actuator-with-feedback-potentiometer/1369170832.html

  2. This is more like a miniature backhoe with a claw. Laughed hard at 1:04- “you can that, and that and…. nope”. A fun project, I agree but when it comes to robotics it’s more like a cargo-cult type thing.

  3. A quick search shows even mini linear actuators like that are close to $100. Still a robotic arm that big would normally cost a fortune, so not totally unreasonable. I wonder how precise it is considering how close the actuators attach to the pivot points, the backlash would be amplified quite a bit at the end of the arm.

        1. You can find these actuators in fancy trash if your a skilled up cycles, I’ve seen them used in power lift chairs ( like gramps has to help him reach a standing position) and they are also used in hospital beds.. now before you get all bent outta shape I wanna mention my friend was given 6 worn out motorized hospital beds and each had 3 of these similar actuators. Pretty comon.

  4. I guess my take on this all depends on what the definition of affordable ends up being. Because I have a strange feeling that the definition of affordable being used in the title and my definition of affordable are quite likely two different things.

    Tho I do have some hulking linear actuators just sitting around >.>

  5. Your comment is awaiting moderation.

    I guess my take on this all depends on what the definition of affordable ends up being. Because I have a strange feeling that the definition of affordable being used in the title and my definition of affordable are quite likely two different things.

    Tho I do have some hulking linear actuators just sitting around >.>

  6. Way too slow for automation, but that can be fixed. Couple cameras and space hardened for the Moon project where it will apparently build spaceships out of Lunar Regolith. Sign me up! (Check speed of delta types with real servos motors – almost too fast to see what is happening – need this kind of speed in factories — https://www.youtube.com/watch?v=Gv5B63HeF1E )
    Seriously cool job. The power to weight looks like a major win.

  7. This is the most positive feedback I’ve ever had on a hackaday post. Thanks! It’s really early days, this ugly duckling is going to be fantastic.
    I’m delighted you have such great suggestions. I look forward to meeting you in person so we can talk about it more.

  8. First of all, I really appreciate the work. I currently work with a (professional) robot arm and would love to build an affordable one for myself. The problem with most of the self-made robot arms is that they are not stable/sturdy enough from a mechanical point of view. As one can see in the video of the project on hackaday.io, the arm shakes after moving which causes many constraints for tasks where precision is neeeded.
    I am wondering how manufacturers like universal robots are able to release their products that are fairly tiny and lightweight but yet strong and sturdy.

    Is that issue solvable or am I wrong in the first place?

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