Anyone have any documentation on the Rethink Robotics Baxter robot? I have picked up a set of arms from one, and eventually I should have the torso portion with the computer. I’m certain that I’ll be missing various components to it. So I was wondering what options might be out there for the control of the arms? It appears that there are 7 motors/axis in each arm. Made from brushless motors with resolvers. I plan to mount it all on a old electric wheelchair base. I’d also like to add in a stereo camera system to allow depth perception and operation from a headset.
Hi @patracy ,
If the baxter is anyway similar to the “spin off” sawyer, your best bet is to use the arms with the torso controller and use ROS1 (with bridges maybe) to control them. As far as I know, the arms have custom developed motor controller boards, which also need a special communication protocol. Even if you get you hands on the sources, which will be quite difficult, getting it to run will take you way longer than an afternoon.
Unfortunately the seller did a absolute crap job packing it. Apparently the idiot thought UPS would only handle the torso in the same way all the time and bubble wrap around the torso would be sufficient. So I’m missing the computer now and the main board on the torso has been damaged as well. One arm appears to be complete. The other arm is missing the plastic shells and some boards it appears. So I’m kinda having to start over from scratch and use the arms/motors. I would like to use a canbus setup and some sort of FOC controller for each motor independently. To further complicate matters, it seems all the motors only have resolvers on them instead of simple hall effect or encoders.
It’s not a rush for it, just something I want to work on as I can. Heck the wheelchair base has sat in the corner of my office for a year or two now after I converted it to RC control.
So I pulled one motor off the incomplete arm. The wiring is actually labeled hall effect. I took the motor and placed it in the lathe to try to carefully cut the end cap off to inspect the board and it does appear that there’s a hall effect sensor setup inside of it. That said, even if it’s not useable, the output shaft side of the gearbox seems to be accessible at all the joints and seems to all have some form of magnetic encoder mounted to them.
I do not have enough knowledge of the motor controller boards, I know that they used a spring on the output side to allow compliant motion and it is also used for force measurement (also employing the hall effect). Just to keep that in the back of your head.