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Firstly, at the $219 price point you can have my money already. Beyond that, things that appeal to me are basically anything which increase the likelihood I ca
by loxias 1y ago
Firstly, at the $219 price point you can have my money already.
Beyond that, things that appeal to me are basically anything which increase the likelihood I can accomplish high dexterous fine motor control skills, for things like tinkering and DIY assembly. I think that would include extra wrist DOF and a longer-reach variant.
Integrated cameras are an interesting idea, but I'd like to be able to swap them out for my own.
My dream is to have some sort of multi-arm table at home. I imagine holding a circuit board, small component, soldering iron, and wire with four robotic arms I control with shaky hands from my laptop. :D
- charleszyong 1y agoSo true. Every time I solder surface mount components, I always wish I could have a steady hand. Sadly, this arm doesn't have that kind of accuracy. The output shaft of the servos we use has about 1 degree of wiggle room and the mechanical structure adds more. To get better accuracy, if sticking with this kind of RC servo, it's basically required to have two servos per joint to preload each other to kill that wiggle room. It's something I've been calculating, but I just can't figure out a way to offer it at a good price. Interestingly, for arms that are popular in academia, even when the price goes to $10k (like ARX or Trossen), the wiggle room is still there (better, but still there).
- fragmede 1y agoeven something twice the price ($438) would still be a great deal. Mind telling us something about your pricing strategy trade-off consideration matrix?
- charleszyong 1y agoDesign for manufacturing is one thing. I did it a lot when building micro gas turbines in college. Sometimes changing the design or manufacturing process will make it 10x faster to make one while not compromising the performance. The second thing is low margin. When people are pricing hardware, they usually plan a 50% to 100% margin to offset various costs that happen in the real world. From what I've heard, in extreme cases, some products cost around $100 while they are being sold at close to $1000. I believe in the Prusa printer approach: you design a good product and price it a little bit above cost. So the company grows with the community. Deep down, there are so many times that I wish I could afford a fancy tool like a Milwaukee drill or a Mitutoyo caliper. And in extreme cases, I really wish I could have a HAAS UMC-400 or even a KERN Micro HD+. Now that I can set the price, I really wish I could make someone get what they want without breaking their bank.
- fragmede 1y agothat's really great, thanks for sharing!
- tdeck 1y agoFor folks curious about why these kinds of margins are built in for hardware products, I found these videos informative: https://www.youtube.com/watch?v=UwrkfHadeQQ https://www.youtube.com/watch?v=UwrkfHadeQQ https://m.youtube.com/watch?v=IdAT_SIRK8c&pp=QAFIAQ%3D%3D https://m.youtube.com/watch?v=IdAT_SIRK8c&pp=QAFIAQ%3D%3D https://m.youtube.com/watch?v=63pnz-z_2sU&pp=QAFIAQ%3D%3D https://m.youtube.com/watch?v=63pnz-z_2sU&pp=QAFIAQ%3D%3D
- TylerE 1y agoAs a customer, thin margins scare the crap out of me. It means you probably won’t be around in a few years.
- ericd 1y agoSeems like this stuff is mostly built on open source, so no need to be too scared.
- fragmede 1y agothat's more scary, not less! Sure, if the worst happens, since it's open source, we'll have the source, but being open source means they've got to figure out a more complicated business model than make thing, sell thing, profit. there are some success stories but also a lot of failures.
- ericd 1y agoI guess I should clarify that it's open source, and seems to be essentially forked from HuggingFace's SO-101, so it's probably not too hard to fall back to that stuff (with fewer features).
- brookst 1y ago
- tdeck 1y agoI was recently trying to get better angular accuracy with servos and minimize backlash. One option that kind of worked was to have a pulley on the servo shaft which wound a string attached to a spring to add mechanical bias. But I ended up giving up and going with 400 step stepper motors instead. They're larger, draw more current, and the drive circuitry is more complicated (it can't get simpler than a PWM servo after all). But they're accurate and significantly quieter.
- 6510 1y agoI know nothing about the topic but could one build some kind of 3d pantograph to scale down the motions?
- nine_k 1y agoWhat you need is to scale down the tolerances. To remove the wiggle room. One of the solutions that does not add a bias that I remember is two identical flat gears on the same axis with a spring that tries to rotate them one relative to another. This removes the wiggle room between this composite gear and the next, regular gear. The motor may have wiggle room, but the gears (which carry angle sensors, don't they?) move without wiggling, and react immediately as you reverse the direction. The load is limited though: the beating surface is twice as small, and the friction is higher.
- numpad0 1y agoI sometimes wonder if it makes more sense to just use those yellow gearboxes, everyone seem to start with SG90s only to reimplement most of the servo part.
- 6510 1y agohave to share the noob thought because it is funny: You could attach an unbalanced wheel to a motor and induce a vibration to maximize wiggling and frequency across the available w-room.
- 6510 1y ago
- DidYaWipe 1y agoWell, based on that info, I guess usability for pick-&-place of surface-mount components on PCBs is out of the question.
- charleszyong 1y agoYeah… the accuracy isn’t good enough. A gantry system is probably needed. There was one robot startup (Haddington Dynamics) figured it out how to do it at a higher price. Sadly they've been acquired and shifted directions I think.
- DidYaWipe 1y agoYep, a gantry is exactly what I was imagining too.
- slow_typist 1y agoThere are cheaper options for soldering SMD-parts on prototype boards. Developing and teaching robot arms to do it would give a good demonstrator but economically it’s a disaster. And mass production is already highly automated.
- taneq 1y ago> it's basically required to have two servos per joint to preload each other to kill that wiggle room Couldn’t you preload with some form of spring?
- charleszyong 1y agoThe advantage of servos is that they can provide constant torque preloading, allowing the preload to be kept low (otherwise, the servo will overheat) but still sufficient. A spring might also be an option if designed properly. I’ll probably give it a try in July.
- taneq 1y agoYou can use a spring with long travel and low K (like a very soft torsional spring, preloaded several turns, or a spring connected by a wire to a drum on the joint) to reduce the change in torque across the range, if that helps?
- bertm 1y agoI had that same thought. I travel a bunch for work and would love to be able to wire up a RPi/Arduino remotely to a sensor or other device and run a test or two.