People are all discussing the technical aspects of the device, which is great and all, but forgetting the one aspect I am in awe of: how googly eyes once again make everything 300% better.
CARA 2.0 – “I Built a Better Robot Dog”
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Re: CARA 2.0 – “I Built a Better Robot Dog”
#22People are all discussing the technical aspects of the device, which is great and all, but forgetting the one aspect I am in awe of: how googly eyes once again make everything 300% better.
A truism that sadly not all are onboard with: https://www.bbc.com/news/articles/c1wl5jp94eno
Re: CARA 2.0 – “I Built a Better Robot Dog”
#23Earlier quoted context omitted.
Could I pursuade you to expand on "Repurposed drone technology has done wonders for legged robots." ? Thanks!
For legged, you want high torque and backdriveability (for shock absorption). 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 frequentl…
This is pretty cool, thanks for sharing. I wish there was a (mostly) 3d printable Cara mini, but I’ll start with Cara.
Re: CARA 2.0 – “I Built a Better Robot Dog”
#24Earlier quoted context omitted.
For legged, you want high torque and backdriveability (for shock absorption). 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 frequentl…
This is pretty cool, thanks for sharing. I wish there was a (mostly) 3d printable Cara mini, but I’ll start with Cara.
The layout is doable with hobby servos, but you'd need to patch in current sensing for that bit of the feedback. It's not terribly difficult conceptually but it's an extra complication that most servo power distribution boards don't give you.
You can also strap a capstan to the servo axle, if that's your thing. I've prototyped that myself in the past. You can go surprisingly far with an FDM printer, an SG90, and some dyneema bowstring. One thing I haven't tried is modding one for continuout rotation to get around the way the capstan drive limits the output angle you can achieve - I was happy reducing from ~180deg to ~45deg for what I was doing - but that's relatively well-trodden ground. Might pull that project out of the storage box it's languishing in at some point.
Re: CARA 2.0 – “I Built a Better Robot Dog”
#253 DOF per leg, so it needs 12 motors and controllers. Getting that under $1000 is nice. 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 t…
It doesn't have to stall to stand still. Or squat, at least. With that leg layout it can safely rest against its backstops when the motors switch off. The drive motors, anyway. The hip motors probably still need to hold vertical balance, but that's intermittent, not a stall load.
Re: CARA 2.0 – “I Built a Better Robot Dog”
#263 DOF per leg, so it needs 12 motors and controllers. Getting that under $1000 is nice. 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 t…
If you read the epilogue, they weren't able to achieve the under $1000 price goal. Total cost ended up being around $1,450. Pretty good price reduction compared to CARA 1.0 though. 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).
It's $1450 if you discount the construction time, as ever. Which ordinarily wouldn't be worth commenting on, but in this case it means rewinding 12 motors which just sounds like an exercise in tedium and hand pain.
Re: CARA 2.0 – “I Built a Better Robot Dog”
#27Earlier quoted context omitted.
If you read the epilogue, they weren't able to achieve the under $1000 price goal. Total cost ended up being around $1,450. Pretty good price reduction compared to CARA 1.0 though. 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).
It's $1450 if you discount the construction time, as ever. Which ordinarily wouldn't be worth commenting on, but in this case it means rewinding 12 motors which just sounds like an exercise in tedium and hand pain.
Only because they didn't know how to ask the vendor to do it for them.
I guarantee this vendor would be delighted to make them to spec at a 1ku volume, max. Rewinding isn't even a meaningful SKU distinction or line retool, it's a configuration parameter.
At 12 motors per product, it's easy to hit MOQ.
Re: CARA 2.0 – “I Built a Better Robot Dog”
#28Earlier quoted context omitted.
It's $1450 if you discount the construction time, as ever. Which ordinarily wouldn't be worth commenting on, but in this case it means rewinding 12 motors which just sounds like an exercise in tedium and hand pain.
Only because they didn't know how to ask the vendor to do it for them. I guarantee this vendor would be delighted to make them to spec at a 1ku volume, max. Rewinding isn't even a meaningful SKU distinction or line retool, it's a configuration parameter. At 12 motors per product, it's easy to hit MOQ.
Reminder that this was a student project.
Re: CARA 2.0 – “I Built a Better Robot Dog”
#29Earlier quoted context omitted.
It's $1450 if you discount the construction time, as ever. Which ordinarily wouldn't be worth commenting on, but in this case it means rewinding 12 motors which just sounds like an exercise in tedium and hand pain.
Only because they didn't know how to ask the vendor to do it for them. I guarantee this vendor would be delighted to make them to spec at a 1ku volume, max. Rewinding isn't even a meaningful SKU distinction or line retool, it's a configuration parameter. At 12 motors per product, it's easy to hit MOQ.
There are inventor programs that'll literally ship you to Shenzhen to build connections to manufacturing sites and even provide you with a liaison, etc. I only know this because I was once in a program that did exactly this.
Re: CARA 2.0 – “I Built a Better Robot Dog”
#30Qugv looks cool and futuristic and has that wow factor, great in expos and milking investors’ money, but practically speaking? They are useless, they have the bad mobility of UGV (compared to UAV), and the bad endurance of UAV (compared to UGV), so they are the mix of worst of both worlds. There’s also other technical issues but yeah, only good for marketing, no matter how they try to push them in defense or whatever, they never materialize.