11–20 of 56 posts
Finally, as I get my proteins denatured by a quadruped-mounted face-finding energy weapon in Civil War II, I can go out singing Stallman's song. You will be free, hackers. You will be free
I have an tangential question about open source projects and names. "Boston Dynamics" is a trademark of Boston Dynamics Inc. Can using "Dynamic" like this project does cause legal problems, considering the name can be an allusion to the trademark?
I have an tangential question about open source projects and names. "Boston Dynamics" is a trademark of Boston Dynamics Inc. Can using "Dynamic" like this project does cause legal problems, considering the name can be an allusion to the trademark?
General Dynamics predates Boston Dynamics by decades.
('General Dynamics' is a wonderful company name. Imagine if you'd heard it for the first time today. Cool name.)
What makes this work is the motors.[1] It's using 3-phase drone prop motors with no gear reduction. With direct drive, the mechanics of the joints are simple. Not too expensive, either. Each motor is about US$120.
I used to work on legged running back in the 1990s. But there were no motors good enough to build a small machine like this back then. All we had were R/C servos, gearboxes, and screw drive actuators. So I was stuck in simulation. All the early legged robots were mechanical nightmares. Springs, cables, pulleys, worm gears, harmonic drives... Now, at last, enough torque in a small package.
What you want in a leg muscle is well known - something that behaves like a spring/damper combo for which you can set the spring constant, the damping constant, and the spring's zero point. People have been trying to do that by mechanical means for decades. There were pneumatic systems, hydraulic systems, things with springs, pulleys, and wires, and a kludge called a "series elastic actuator", which is a stiff spring-damper combo in series with a screw drive actuator. They're all terrible.
"You cannot strip the teeth of a magnetic field" - GE electric locomotive sales rep, early 20th century.[2] That's why they can drop this thing and have it spring back. Try that with any of the mechanical nightmares and the results will not be good.
I have an tangential question about open source projects and names. "Boston Dynamics" is a trademark of Boston Dynamics Inc. Can using "Dynamic" like this project does cause legal problems, considering the name can be an allusion to the trademark?
I doubt it. Canadian chain restaurant 'Boston Pizza' can't prevent you using the word 'pizza', though it's directly concerned with their business. General Dynamics predates Boston Dynamics by decades. ('General Dynamics' is a wonderful company name. Imagine if you'd heard it for the first time today. Cool name.)
Hmmm, just looked it up: "Boston Dynamics is an American engineering and robotics design company founded in 1992" Boston Acoustics was founded in 1979. Th A40s on my desk came out in 1986, bu6t I'm not sure how old this specific pair are, I bought them 2nd hand. I have a pair of their bigger brothers, the A60s downstairs that I bought new in 1988...
Very nice. What makes this work is the motors.[1] It's using 3-phase drone prop motors with no gear reduction. With direct drive, the mechanics of the joints are simple. Not too expensive, either. Each motor is about US$120. I used to work on legged running back in the 1990s. But there were no motors good enough to build a small machine like this back then. All we had were R/C servos, gearboxes, and screw drive actua…
Edit, also what happened that made electric motors so much better since the 90’s? It’s not like we made groundbreaking discoveries about magnetism, right?
Very nice. What makes this work is the motors.[1] It's using 3-phase drone prop motors with no gear reduction. With direct drive, the mechanics of the joints are simple. Not too expensive, either. Each motor is about US$120. I used to work on legged running back in the 1990s. But there were no motors good enough to build a small machine like this back then. All we had were R/C servos, gearboxes, and screw drive actua…
If I'm understanding correctly, this is not accurate. The paper and the Github repository describe it as a "dual stage timing belt transmission with a 3:1 gear reduction on each stage".
https://github.com/open-dynamic-robot-initiative/open_robot_...
Very nice. What makes this work is the motors.[1] It's using 3-phase drone prop motors with no gear reduction. With direct drive, the mechanics of the joints are simple. Not too expensive, either. Each motor is about US$120. I used to work on legged running back in the 1990s. But there were no motors good enough to build a small machine like this back then. All we had were R/C servos, gearboxes, and screw drive actua…
It's 3:1 belt drive reduction.
I was involved in building --or more accurately, rebuilding-- one. I went as far as doing a whole new design CNC-machined out of aluminum.
One of the problems with this design is that these drone motors are not designed for static operation drawing lots of current without any cooling whatsoever. The 3D printed plastic parts are pretty much insulators. We had one motor smoking. The thing could not stand due to its own weight. This (and other factors) led to thinking of a new design using similar principles, a better motor and an aluminum structure that could be used to move some of the heat away from the motors.
Finally, as I get my proteins denatured by a quadruped-mounted face-finding energy weapon in Civil War II, I can go out singing Stallman's song. You will be free, hackers. You will be free
Energy weapons are expensive to build. Chemical weapons are cheap. The War of the Machines is going to be all nerve gas, all the time. :(
Very nice. What makes this work is the motors.[1] It's using 3-phase drone prop motors with no gear reduction. With direct drive, the mechanics of the joints are simple. Not too expensive, either. Each motor is about US$120. I used to work on legged running back in the 1990s. But there were no motors good enough to build a small machine like this back then. All we had were R/C servos, gearboxes, and screw drive actua…
> no gear reduction It's 3:1 belt drive reduction. I was involved in building --or more accurately, rebuilding-- one. I went as far as doing a whole new design CNC-machined out of aluminum. One of the problems with this design is that these drone motors are not designed for static operation drawing lots of current without any cooling whatsoever. The 3D printed plastic parts are pretty much insulators. We had one moto…