Every few months or so, a new video from Boston Dynamics will make the rounds on the Internet. This is their advertising, because unless the military starts buying mechanical mules, Boston Dynamics is going to be out of business pretty soon. You’ll see robots being kicked down the stairs, robots walking through doors, and robots acting like dogs. If a hundred or so highly skilled and highly educated roboticists, technologists, and other experts can put together a walking dog robot in a decade, obviously one person can cut through the cruft and build one in a basement. That’s what [Misha] is doing. It’s the Dizzy Wolf, a robotic wolf, or dog, or cat, we don’t actually know because there’s no fur (or head) yet. But it is interesting.
The key component for any quadruped robot is a high-torque, low-noise servo motor. This isn’t a regular ‘ol brushless motor, and for this application nine gram servos go in the trash. This means custom made motors, or DizzyMotors. You’re looking at a big brushless motor with a planetary gearset, all squished into something that could actually fit into the joint of a robotic wolf’s leg.
There’s a driver for these motors, strangely not called the DizzyDriver, that turns a BLDC into a direct drive servo motor. It is effectively a smart servo, that will move to a specific rotation, receive commands over RS-485, and write back the angular position. It also applies constant torque. Of course, there is a video of the DizzyMotor and servo driver below.
Building a robotic dog that will walk around the house is one of the hardest engineering challenges out there. You’ve got fairly crazy kinematics, you’ll need to think about the strength of the frame, control systems, and eventually how to fit everything in a compact design. This project is hitting all the marks, and we can’t wait to see the Dizzy Wolf do a backflip or chase a ball.
Wow, that hybrid gimbal / stepper / gearbox is a work of art.
I would love to have these available for my motion control projects!
Brad
Any idea on the cost? It seems the GBM8028 motor he started with was $150 from aliexpress. How much would that gearbox cost to make?
Oof, that gearbox ain’t gonna be cheap. I wonder what happened to the 3d printed cycloidal gearbox that was featured a while back? It seems more builder-friendly.
Theoretically most of the gearbox could be cut out with a laser or water jet, so – probably way cheaper then the motor itself.
If you’re the radicalbrad behind the vulcan-74, I can only imagine what your motion control projects must be like! Hit the tipline!
Seems like a good platform to apply NN learning to in order to teach it to walk! Pretty sure that recently there was an article about that robot leg that learned to walk on it’s own.
https://www.sciencealert.com/this-robot-leg-learned-to-walk-all-by-itself-without-any-programming
“Every few months or so, a new video from Boston Dynamics will make the rounds on the Internet. This is their advertising, because unless the military starts buying mechanical mules, Boston Dynamics is going to be out of business pretty soon.”
Start making ED-209’s.
There is another remake or boston dynamic robot but opensource https://www.personalrobots.biz/spotmicro-is-an-open-source-robotic-dog/
This is some very interesting and promising stuff!
Looks familiar, was this at EMFCamp?
You might also be thinking of the one out of MIT/MITERS
https://build-its-inprogress.blogspot.com/2019/03/hello-there-mini-cheetah.html
https://build-its-inprogress.blogspot.com/2016/02/planetary-gearboxes.html
https://build-its-inprogress.blogspot.com/2018/07/fixed-noise-and-thermal-testing.html
Oh wow, a mini twirk!