Does anyone have any suggestions on something that's a little higher quality, i.e. more torque and larger, like the size of a UR5 but cheaper than $30k? There's always seems to be a gap between "robot arm with dynamixels/off the shelf servos" and "research-grade arms".
I’m very happy with the mechanical design for my four axis brushless motor powered robot arm with integrated 3D printed planetary gearboxes. I have some hope of picking the project back up and better documenting it, though the CAD files explain a lot. For the last few years I’ve been working on my own brushless motor controller design and I think this year I will have that stable enough to go back to working on this arm.
Pretty neat! As a fellow motor controller designer, I worry you're wasting time reinventing the wheel in that regard, but I really like your project, I also want a farming robot.
Thanks. I specifically want something that is designed in kicad, open source, and easy to manufacture at JLCPCB using parts already in stock there. Maybe there are more options now but two years ago when the Odrive we were using was discontinued and their new products got more closed source and more expensive, we didn’t have a lot of options. At this stage I’m very happy we’ve gone with our own design because we have so much flexibility on packaging and specification. Working with third party devices sucked.
This is awesome! I don't have enough background knowledge to know how to make one myself, do you ever plan to sell these, or make a tutorial on how to build one?
Thank you! I do not plan to sell these arms. I am not sure if I will be able to make time to document it (I am maintainer on an open source farming robot project which takes up most of my time - see profile), but I am working on a new actuator concept based on the principles explored in this design, and my goal with the new actuator concept is to document that and make it more general purpose, so it is easier for people to make themselves and explore this mechanical gearbox design. This should hopefully popularize this design if others like it. I think is fair to say the design is probably novel.
A fun fact about the new actuator is that it can be printed in plastic at home but is designed to be 3D printed in 316 stainless steel. I was inspired recently by the relatively low cost of 3D printing from China (I used craftcloud), and my novel actuator design relies on the fact that 3D printing allows gearbox components and robot frame members or components to be mechanically unified. This opens up new design spaces.
In this design, it is a two stage planetary with one "first stage" in between two parallel second stages. The first stage is driven by a shaft from a side mounted motor, with the shaft going through the gears in one of the second stages to reach the first stage sun gear. This parallel output better balances mechanical loads across the joint both on the input and output sides. This makes it ideal for elbow and knee style joints, and might serve to be genuinely very useful in robotics worldwide.
As with all my work it will be open source. I don't love twitter but that is currently the best spot to get updates on side projects like this. I am @tlalexander there. Alternatively, star the 3D printed robot arm repo and I will update it when my new steel servo design is done!
I have a dobot mg400 but there are quite a few others: uFactory, elephant robotics, annin, dorna, epson (vt6L and their scaras), and lynxmotion is releasing their ses-v2.
Wow, thanks for the list of resources. My problem with most robot arms are either they have small payloads, accuracy isn't very high, are too slow, or software support is terrible. Do you have any specific suggestions for 6DoF? The MG400 looks to have 4.
What payload are you looking for? Cartesian Gantry’s are your next bet if you want to handle higher loads. Eg. Epson vt6l is ~14k but I’m sure you can build a gantry system to handle higher loads for a bit less!
Dobot software sucks though, I ended up programming it in python. It’s definitely not on the same level as say a Kuka or Yaskawa. Epson seems like the best value out of all the higher end arms. Software looks good, the arms are built well, has a long history in industry, and price is decent
There are a couple of arms commonly used in research around the $10k mark, namely the Franka Emika and UFACTORY xArm 6.
The ALOHA project uses the ViperX 300 6DoF, which is around $6500 but uses higher quality dynamixels with aluminum parts and bills itself as "research grade". I have one of these and I'd say it's expensive for what you get, but still cheaper than the "factory grade" robots. I will need a bimanual setup eventually and I'm probably going to get either an Emika or xArm since I'm already hitting the weight limits of the ViperX.
I‘m not sure as far as your technical requirements go, maybe Igus.eu would fit your needs? They do have a fairly good robot automation portfolio that seems to be very price competitive as far as I can tell
