[HN Gopher] Stanford Pupper low cost quadruped robot
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Stanford Pupper low cost quadruped robot
Author : msadowski
Score : 259 points
Date : 2020-05-03 14:59 UTC (8 hours ago)
(HTM) web link (stanfordstudentrobotics.org)
(TXT) w3m dump (stanfordstudentrobotics.org)
| softwarejosh wrote:
| should not be 600 those servos are pricey
| NathanKau wrote:
| You can buy the CLS6336HV servos from JX-Servo directly for
| about $25 each. Usually a much better deal than on Aliexpress,
| Banggood etc and it's pretty easy to do. The $600 price point
| though assumes you have a number of things already like a RPi,
| lipo charger, or PS4 controller.
| ge96 wrote:
| I summed the BOM table it was just over $330 but it looks like
| that's just body no electronics at all... the servo arms look
| special/priciest but it's multiplied. I imagine the main thing
| for this aside from body is the brain but that looks to be
| shared as well
| bittercynic wrote:
| About $30 each on aliexpress. Seems like an ok deal to me.
| aszantu wrote:
| Someone pls build this for grannies
| https://twitter.com/aszantu/status/1257007725277597698?s=20
| lee wrote:
| Watching this is really heartwarming. It's inspiring to see young
| talented minds directed towards curiosity and engineering while
| also sharing the fruits of their labor for everyone else to
| benefit. Kudos to the team!
| isalhi wrote:
| Gotta say, really comforting that this was written in python.
| Everyone I talked to when it comes to quadrapeds tells me python
| is too slow for my projects.
| ebg13 wrote:
| People always imagine that mobile robotics needs nanosecond
| response times or some other silliness when the reality is that
| your sensors and servos only operate on the order of 100Hz.
| msadowski wrote:
| I came across this project while working on my newsletter and
| thought HN might appreciate this. With the $500-600 price I'm
| heavily thinking of building one for myself.
|
| If someone would like to build something larger then Stanford
| Dogg (https://github.com/Nate711/StanfordDoggoProject) is one
| choice, however as far as I remember the price comes to around
| $3k for parts only.
|
| Even cheaper alternative to Pupper could be OpenCat
| (https://www.petoi.com/) however it was never fully open source
| and I don't think it's available anywhere.
| kevinphy wrote:
| An open source low cost 5-axis robotic lamp
|
| https://hackaday.io/project/21637-documentation-assistant-ro...
| bitwize wrote:
| But can it be trained to bounce or balance on a rubber ball?
|
| https://youtu.be/FI0T0Oj7WFE
| wslh wrote:
| What is the cheapest robot you can build? This robot is pretty
| expensive, is much more than a Lego Mindstorms EV3, Bandai
| Smartpet Robot Dog is USD 157 in Amazon.
|
| I am mainly thinking about a "one robot per child" initiative.
| inetsee wrote:
| There seem to be two versions of the Bandai Smartpet Robot Dog
| on Amazon, one in black for $157 (that's out of stock at the
| moment) and one in white for $60. I don't know why there's such
| a high price difference, especially since there doesn't seem to
| be any functional difference between the two.
| weinzierl wrote:
| From watching the demo video: This thing seems amazing and for
| around USD 600, buildable in 8 to 10 hours, within hobbyists
| reach. The demo reminded me much of the Boston Dynamics ones but
| without the creep. I guess that has much to do with the fact that
| the Pupper is much smaller than Boston Dynamics' monsters.
|
| EDIT: They latter address this in the demo video: _" We
| specifically avoided to make them just look like dogs. I think
| when you're on[sic] the uncanny valley that would be a little bit
| weird."_
| syntaxing wrote:
| For about the same price, you can build a "spot micro" [1] if you
| have a 3D printer. I haven't build one myself (yet) but it's been
| fun following them. I came across them when someone in HN posted
| how to train it using OpenGym (will find the link when I'm not on
| mobile).
|
| [1] https://gitlab.com/custom_robots/spotmicroai
| krisoft wrote:
| Do you happen to have a video of the spot micro actually
| walking? I can't seem to find any.
|
| It is easy to make a spot shaped object. Making it walk is the
| hard part.
| TaylorAlexander wrote:
| You got me curious. A direct search on youtube nets this:
|
| https://www.youtube.com/watch?v=pRCBEaGtxuU and this:
| https://www.youtube.com/watch?v=tW3fp6nHbqk
|
| But it would be nice to see some more advance walking.
| syntaxing wrote:
| This is the link to the OpenGym I mentioned before. There's a
| couple video on their slack/discord(?) channel. I have to dig
| for it though.
|
| https://github.com/nicrusso7/rex-gym/blob/master/README.md
| mrfusion wrote:
| Should I build this or spot micro?
| https://www.thingiverse.com/thing:3445283
| NathanKau wrote:
| The SpotMicroAI project has a great community on its Slack, but
| the project is a bit more in its infancy than Pupper. For
| instance, spot micro doesn't have the software right now to
| make it walk quickly or trot. Pupper is at a v1.0 stage with
| software and build instructions already complete, but it's
| potentially more expensive to build than spot micro.
| mrfusion wrote:
| Any idea how much the spot micro would cost?
|
| I'd enjoy working on the software to make it walk.
| krisoft wrote:
| I don't want to talk bad about anyone's project. This is the
| first time I'm seeing both of these projects and the Stanford
| Pupper looks a lot more promising.
|
| My heuristic is the following: Legged robotics is hard. Four
| legged robots are even harder than six legged ones. Using hobby
| servos makes the task even harder. You can find a lot of
| succesfull hexapod projects with hobby servos but up until
| fairly recently no four legged ones.
|
| These robots operate in a very thight spot of the design space.
| The motors have to be fast enough to be responsive, but torquey
| enough to bear the dynamic loads. The mechanism has to be
| compliant enough to not overstress the gears but not too
| springy lets the robot collapse into a mess. The structure has
| to be rigid enough to support the forces, but also light enough
| so the legs can carry it. All in all designing a four legged
| walking robot with hobby servos is a hard problem. It is very
| easy to put together something which looks like a dog robot and
| even easier to feel that once the hardware is there from then
| on it is only a software problem to make it walk. For many
| possible designs that is false. Not even the best software
| could make them work.
|
| This is what i know about the problem space. And then I look at
| the spot micro. It looks awesome. Clearly they made it to mime
| the spot mini robot. The problem is that all that is
| superflous. It is a design fetish. Maybe they put in all the
| effort to design the right leg lengths and the appropriate
| springyness and carefully considered the torque and thermal
| limits of those servos and come to the conclusion that they can
| afford the extra grams. But it is more likely that they did
| none of that and just made the 3d drawings look cool.
|
| If you build the Stanford Pupper you will eventually probably
| end up with a walking robot. The video where they show it
| perform on the stage is a pinacle of a lot of tweaking and
| design work. I just don't see the same about the spot micro.
| A4ET8a8uTh0 wrote:
| This is the kind of the stuff that makes me wanna dust off my
| raspberry. I do have a vacation coming up. Maybe I should pencil
| in some fun time since it is a staycation anyway.
| phreeza wrote:
| Is it really a vacation if you have to pencil in fun time?
| A4ET8a8uTh0 wrote:
| I know it did not sound right, but between forced stay at
| home, in practical sense, we can't really go anywhere so we
| agreed on some home projects. It is not a true vacation, but
| it will be departure from regular routine.
| sixothree wrote:
| For me, vacations are opportunities for exploration. Taking
| time for hobby projects is difficult on time that isn't a
| weekday evening.
| NathanKau wrote:
| Hey all, my group in Stanford Student Robotics made Pupper. Happy
| to answer any questions!
| canada_dry wrote:
| Awesome project! I'd love to build one, except for sourcing the
| parts - esp. the carbon fibre (out-of-stock) bits! If your team
| sold it as a kit I'd be your first customer! Of course, you'd
| have to ship to Canada too.
|
| Q. Was there a price point you had to aim for in the
| development (i.e. under $1K)? And, if you were to double the
| price, what improvements would you make (e.g. even better
| servos)?
| NathanKau wrote:
| We're actually working with some people who are interested in
| selling the kits as a side project. Stay tuned. With double
| the BOM cost, we'd use torque-controllable servos. We're
| testing out the DJI M2006 right now.
| e-_pusher wrote:
| Awesome project Nathan, kudos to the team. I'd love to use the
| Stanford Pupper at some point for K-12 outreach efforts myself.
|
| I reviewed your power distribution board. I think it needs more
| safety features before it can safely be entrusted to the hands
| of K-12 kids. Couple of comments:
|
| - The battery input is unfused. I would HIGHLY recommend adding
| one.
|
| - I know you guys wrote in Github about how people should not
| plug in voltages above 8.4V, and not overdischarge batteries,
| but I would not trust K-12 kids to follow those instructions :)
|
| It would be best to add a overvoltage, overcurrent and reverse
| polarity protection circuits. Those are pretty simple and
| should not take much space on the board. Jerri Ellisworth has a
| great video where she explains these circuits in detail, and
| how to make them low-cost:
| https://www.youtube.com/watch?v=QZ0WXQWND-I
|
| - I would add a schmitt trigger circuit to sense the battery
| voltage and feed that as a digital input to the Raspberry Pi.
| If the batteries are too low, the Pi then can throw an audible
| alarm and disable the servos. This would prevent kids from
| overdischarging their batteries.
|
| As a future addition, I think it would be sweet to add a Teensy
| somewhere. Then students would be able to easily add extra
| sensors and have their robot respond to changes in the
| environment etc. So much potential for fun.
|
| Congrats again!
| NathanKau wrote:
| Great feedback! Will definitely incorporate those features
| into future revisions.
| Animats wrote:
| It's fun seeing these. As batteries and motors get better, they
| get more agile.
|
| I'm disappointed that there's no force feedback. They're still
| using dumb PWM servos, which is a 1970s technology. There are
| better servos, from Dynamixel, where you get info back. There was
| a project called OpenServo [1] to smarten up dumb servos by
| developing tiny new controller boards for cheap RC servos. But
| that project seems to be defunct.
|
| There are lots of good legged toy robots in the $300-$400 range,
| but without good feedback you can't do Boston Dynamics type
| stuff.
|
| [1] https://hackaday.io/project/158267-openservo-20
| NathanKau wrote:
| We've found you can actually do a lot with dumb servos and
| orientation feedback and get visually similar results to Spot.
| For instance, we get hopping, trotting, strafing, turning +
| strafing, walking. What it can't do is prancing or a flying
| trot. But we think it's totally worth it since a good-enough
| servo is around $20, while similarly sized torque-controllable
| servo (excluding dynamixels, which don't actually have torque
| control), runs about $400 each. DJI did actually come out
| recently with their M3508 and M2006 which we're starting to
| play with, and we think we can build a torque-controllable
| pupper for about $1.5k.
|
| The main limitation I think for servo robots with kinematic
| (position-control) controllers is speed. We're moving around
| 0.8m/s max, while the new Unitree A1 is something like 3.5m/s.
| lukevp wrote:
| Ah a perfect use for that routed carbon fiber I have laying
| around...
| canada_dry wrote:
| > Req'd: _routed carbon fibre_
|
| About 50% of makers have a 3D printer... a CNC for carbon fibre
| routing... I'm guessing 1%.
|
| Very slick build for the price point though. 1/10th the price of
| something like: https://www.youtube.com/watch?v=dwdd2Bv94iw
| 542458 wrote:
| Sure, but you don't personally need the CNC. All you need is to
| know somebody who is in that 1%. Or have access to a makerspace
| with that CNC.
| NathanKau wrote:
| You can buy the carbon fiber parts here!
| https://great3d.com/stanford-pupper-robot-carbon-fiber-parts...
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| kanwisher wrote:
| Finally a cool project for lockdown. Definitely think I'm
| building this
| mrfusion wrote:
| Has anyone heard of an open source build able bipedal robot? For
| some reason that's what I'm really interested in building.
| NathanKau wrote:
| There's blackbird, but not sure of its current status.
| https://hackaday.io/project/160882-blackbird-bipedal-robot
| amelius wrote:
| What kind of control algorithms do they use for robots like
| these?
| serf wrote:
| the simple gaits are usually PIDs that integrate requested
| control directions and gyro data, bounded by maximum servo
| speed.
|
| here's an informative youtube video that's all about
| quadrupedal dog-style robots.[0]
|
| fancier gaits integrate elements that measure leg length and
| foot pressures.
|
| [0]: https://www.youtube.com/watch?v=4MGZvcd0xxc
| n0us wrote:
| > You can buy most of the parts directly from a reseller like
| Amazon or McMaster-Carr, but for some you'll need to get them
| custom manufactured for you. The custom parts include the carbon
| fiber routed parts, the 3D printed parts, the power distribution
| printed circuit board, and the motors.
|
| Very cool and I would like to build this, but the "Nano Dog" is
| probably a cheaper and more approachable option for the garage
| engineer.
|
| https://www.thingiverse.com/thing:3145690
| ipsum2 wrote:
| I wasn't able to find any examples of this quadruped walking.
| andybak wrote:
| > the "Nano Dog" is probably a cheaper and more approachable
| option for the garage engineer.
|
| Hard to find out much about that or OpenDog in general. I've
| found videos and 3d printer files but nothing that I can read
| to understand what it can do and why I might want to build it.
|
| Or do I really have to watch a bunch of YouTube videos? I hate
| video.
|
| Have I missed the actual project page somehow?
| rspicer wrote:
| https://github.com/XRobots/miniDogV2
|
| The code's a bit of a mess -- James is clearly not a software
| engineer first. This is totally understandable, given that he
| does so many other things!
|
| When I first saw the code, I thought about doing a
| refactoring pass and making a pull request. It would be
| painful to test correctness without the hardware, and I don't
| want to make things worse, so I haven't.
| monocasa wrote:
| Oh wow, you're not joking. I'm getting flashbacks to when I
| supported a team of EEs.
| dmoy wrote:
| Hell, I'm getting flashbacks to _my own_ code in EE lab.
| Except this stuff looks way less messy, not nearly enough
| random assembly declarations to bludgeon a register or
| pin into submission.
| n0us wrote:
| Good point, now that I am searching for it I cannot seem to
| find the code. At the same time it still does not require
| custom manufactured parts or circuit boards which makes the
| barrier to entry (and importantly price) a bit lower unless
| the Stanford folks setup a store.
|
| I make an internet promise here and now that if I ever build
| the robot I'll open source the source code to control it.
| softwarejosh wrote:
| the parts list for the puppet is a joke everything is overkill
| for no reason you could easily do it for 200 same size and
| function
| detaro wrote:
| Now we're curious about what part replacements you'd suggest.
| TaylorAlexander wrote:
| I've built several servo powered walking robots. Torque is a
| major concern, and obviously weight plays a part in how much
| torque is required. The recommended servos look to be $30
| each, x12 means $360. If you spent $200 just on servos you'd
| have to settle for $16 servos. Probably less torque. That
| would mean that at full leg extension the robot might not be
| able to support itself. That would be an annoyance when
| trying to focus on walking algorithm development, which is
| usually the fun part for these small walkers.
|
| You can definitely do something for cheaper, but I wouldn't
| call this a joke. When I was 15 (20 years ago lol) I designed
| an 18 servo hexapod. I saved up $350 from cleaning horse
| stalls and my dad agreed to pay the other half, and I spent
| $700 on servos. It was great to learn about inverse
| kinematics before ever setting foot on a college campus!
| billconan wrote:
| For carbon fiber parts (used for the chassis and legs), I
| wonder if it is possible to carve them out out from the same
| power distribution PCB board. Some PCB manufacture seems to
| support custom shapes.
|
| But the PCB material must be heavier than carbon fiber, not
| sure if it will affect the robot dynamics.
| NathanKau wrote:
| Just for fun I uploaded the top and bottom body panel DXFs to
| jlcpcb and they're only about $2 each. That's compared to
| about $30 to have them cut out of carbon fiber, and of course
| you don't get to put circuity like your power distribution on
| it for free.
| bitwize wrote:
| So will they build a super-inexpensive, Christmas-present version
| around an Arduino and call it the Pupperino?
| paulclinger wrote:
| This gihub link may be a better one, as it provides demos,
| hardware, software, and design descriptions along with the
| schematics, pictures, and ICRA paper reference:
| https://github.com/Nate711/StanfordDoggoProject
| detaro wrote:
| But is a different project for a bigger and more expensive
| design.
| msadowski wrote:
| Here is a GitHub link to the actual Pupper project:
| https://github.com/stanfordroboticsclub/StanfordQuadruped and
| not to Stanford Doggo.
| ge96 wrote:
| I want this but where it's self-piloting/long lasting(battery)
| and can build a point-cloud of my apartment as it navigates. Also
| one for outdoors just wanders in a farm or something... I don't
| know has no purpose but "neat". Maybe you program it to do a
| routine where it walks around takes photos of things throughout
| the day, self charges.
|
| edit: to clarify this isn't a negative comment/criticism. I'm
| saying I fantasize about having a platform like this but with the
| capabilities I mentioned(which I'm aware is not easy).
|
| Currently I can't even program/make that gait that makes it move
| so smoothly so I'm definitely not criticizing.
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(page generated 2020-05-03 23:00 UTC)