https://github.com/tlalexander/brushless_robot_arm
https://github.com/Twisted-Fields/rp2040-motor-controller
Direct link to a video of it operating (apologies for the Twitter link) here: https://x.com/tlalexander/status/1455339851734138880
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!
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
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.