Here's the US$18 motor: [1] Those things are getting really cheap. He did have to rewind it, though, for more turns with thinner wire. The manufacturer mentions that you can order with "custom Kv", which means you might be able to get a different winding from the factory if you order a reasonable quantity. Especially if you tell them that makes them "robot motors".
Motor overheating might be a problem. The dog, just standing, has its motors stalled under load, converting power to heat. Drones don't do that. Temperature feedback would help if this thing has to operate for extended periods. Remember yesterday's article on humanoid robots and their cooling problems.
The motor controller is nice too, and cheap at $49. Needed fixes to the firmware, but that's not surprising at the price. High performance motor controllers used to cost about $1000.
Repurposed drone technology has done wonders for legged robots. We're not quite at the point where limb drive hardware is off the shelf, but it's way better than it used to be.
[1] https://www.xntyi.com/tyi-5008-kv335/kv400-high-speed-brushl...
The Nao robot[0] had this exact problem and of course no way to fail gracefully. I recall checking its basic functions with my lab partner in college. I looked away for a moment and that was when it went down hard. Me and the other guy locked eyes in an "oh fuck" moment, as the robot was expensive and our thesis supervisor went through quite a lot of paperwork to have it funded. Fortunately it was intact and none of us mentioned this incident to anyone.
Agricultural drone motors like the eaglepower 8308 are ideal.
They’re cost effective, (~$80 from aliexpress) & you can pair them with a 3d printed cycloidal drive to fulfill both requirements.
Industry actuators are an order of magnitude more expensive than this.
Extra: If you go down this path, you’ll need a driver. The Xdrive is frequently recommended, but there’s a clone that’s significantly cheaper: https://makerbase3d.com/product/makerbase-xdrive-mini-high-p...
Rather than thermistors all over the place, perhaps an onboard program could calculate motor temperature by integrating current sent to each over time—assumed some degree of cooling (and perhaps here a single temperature sensor might measure ambient temperature of the environment… or could just assume "indoor temperature").
Hypothetically if I were to want a quadrupedal robot to experiment with it's not an impulse buy/build, but getting closer to that point... whereas $3000+ is a hard pass (e.g. Apple Vision Pro territory).
Brakes for robot joints are common in industrial robots. They're usually part of the emergency stop system. If power fails, the controller crashes, or someone pushes the emergency stop button, spring-driven brakes lock all major joints to stop all motion.[1] That might be useful in a quadruped, which can park without active balance.
[1] https://www.techbriefs.com/component/content/article/28812-c...
The answer is that jobs mostly don't exist for this kind of work.
The robotics jobs that do exist are basically large manufacturing robot development (think fixed place arms in car production), warehouse automation (amazon, etc), autonomous driving (originally agricultural, but now also things like waymo/tesla), and DoD style work.
And even then - the number of real positions is minuscule compared to other software roles.
So instead I build robots in my personal time as an expensive hobby (and man is it expensive...).
I'm somewhat jealous of the folks who've managed to monetize that expensive hobby by filming it and putting it on youtube, but I've also seen exactly how much time/effort/luck goes into being successful there - and I think it'd kill any joy I have for it.
Plus the demand is higher for software than it is for hardware most of the time. Pretty hard to find jobs in robotics compared to all the various kinds of software.
Founders I talk to that are doing hardware, broadly speaking, say it's a competitive advantage as it's not as crowded. Content like Aaed's will hopefully nudge more people into it.
It can take 6 months once your product is finished to be legally allowed to sell it and even then it could be forced to be recalled or be redesigned. It’s a much more difficult environment to deal with vs I spent a few months throwing together this slop code, thanks for my multi-million dollar buyout.
And, if you can scale that up, then why even mention it? It's not relevant.
Also BLDC based motors in bots seem to be popular now, used to be steppers and harmonic drives from what I remember reading.
Idk why electrostatic actuators aren't getting more popular like HASEL and a few papers on ones using fiber pumps come out recently. I suppose the danger that the high voltages present hmmm.
But surely we can replicate muscle fiber actions magnetically, just need some sort of crazy micro manufacturing process to make the magnets.
Considering what muscle fiber looks like on the molecular level you're literally describing nanotechnology and the associated nanofabrication techniques. Surely it's possible to do but we don't seem to be there just yet.
Depending on the max speed of the motors/legs, giving it longer foot pads might be necessary for a good gallop. Intuitively, it looks a bit... "low gear" in the videos.
My first project as a research assistant in AI was doing evolutionary algorithms on Khepera robots, which had a virtual Java implementation. We were able to evolve some pretty cool behaviors, although I don't know what would have happened if we had uploaded them into a physical Khepera robot.
I also wonder if you can read the impact force from the legs with the ground from the motor controllers (should be able to infer that from motor current + leg displacement). Learning to gallop without "feeling" the legs impacting sounds extremely difficult.
This is spectacular as a reference, which youtube isn't
