
Stanford Pupper: low-cost quadruped robot - msadowski
https://stanfordstudentrobotics.org/pupper
======
n0us
> 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](https://www.thingiverse.com/thing:3145690)

~~~
softwarejosh
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

~~~
TaylorAlexander
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!

~~~
jsjohnst
> You can definitely do something for cheaper

If the 35kg is in fact needed (which I’m not prepared to debate, probably
needed, but I can’t prove / disprove), you are exactly right. Yes, you could
maybe save a couple dollars with cheaper servo brands, but honestly for a 35kg
servo, you’re going to pay a decent amount for 12 of them.

~~~
TaylorAlexander
Yes and I noticed this robot can jump completely off the ground. Pretty nice!

------
paulclinger
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](https://github.com/Nate711/StanfordDoggoProject)

~~~
msadowski
Here is a GitHub link to the actual Pupper project:
[https://github.com/stanfordroboticsclub/StanfordQuadruped](https://github.com/stanfordroboticsclub/StanfordQuadruped)
and not to Stanford Doggo.

------
NathanKau
Hey all, my group in Stanford Student Robotics made Pupper. Happy to answer
any questions!

~~~
e-_pusher
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](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!

~~~
dekhn
I can't emphasize enough how much overvoltage, overcurrent, and reverse
polarity protection has saved me when wiring stuff.

------
Animats
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](https://hackaday.io/project/158267-openservo-20)

~~~
NathanKau
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.

------
weinzierl
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."_

------
msadowski
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](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/](https://www.petoi.com/)) however it was never fully
open source and I don't think it's available anywhere.

------
A4ET8a8uTh0
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
Is it really a vacation if you have to pencil in fun time?

~~~
sixothree
For me, vacations are opportunities for exploration. Taking time for hobby
projects is difficult on time that isn't a weekday evening.

------
syntaxing
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](https://gitlab.com/custom_robots/spotmicroai)

~~~
krisoft
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
You got me curious. A direct search on youtube nets this:

[https://www.youtube.com/watch?v=pRCBEaGtxuU](https://www.youtube.com/watch?v=pRCBEaGtxuU)
and this:
[https://www.youtube.com/watch?v=tW3fp6nHbqk](https://www.youtube.com/watch?v=tW3fp6nHbqk)

But it would be nice to see some more advance walking.

------
lee
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!

------
mrfusion
Should I build this or spot micro?
[https://www.thingiverse.com/thing:3445283](https://www.thingiverse.com/thing:3445283)

~~~
NathanKau
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
Any idea how much the spot micro would cost?

I’d enjoy working on the software to make it walk.

------
ge96
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.

------
canada_dry
> 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](https://www.youtube.com/watch?v=dwdd2Bv94iw)

~~~
NathanKau
You can buy the carbon fiber parts here! [https://great3d.com/stanford-pupper-
robot-carbon-fiber-parts...](https://great3d.com/stanford-pupper-robot-carbon-
fiber-parts/)

------
kevinphy
An open source low cost 5-axis robotic lamp

[https://hackaday.io/project/21637-documentation-assistant-
ro...](https://hackaday.io/project/21637-documentation-assistant-robotic-lamp)

~~~
bitwize
But can it be trained to bounce or balance on a rubber ball?

[https://youtu.be/FI0T0Oj7WFE](https://youtu.be/FI0T0Oj7WFE)

------
wslh
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
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.

------
vladletter
Don't hesitate to get involved.
[https://stanfordstudentrobotics.org/getinvolved](https://stanfordstudentrobotics.org/getinvolved)
:)

------
isalhi
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
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.

------
mrfusion
Has anyone heard of an open source build able bipedal robot? For some reason
that’s what I’m really interested in building.

~~~
NathanKau
There's blackbird, but not sure of its current status.
[https://hackaday.io/project/160882-blackbird-bipedal-
robot](https://hackaday.io/project/160882-blackbird-bipedal-robot)

~~~
canada_dry
Looks dead. The guy's website [i] expired and his github [ii] hasn't seen
activity in 9mos. Too bad, that did look like a very slick project!

[i] [https://www.gabrael.io/](https://www.gabrael.io/)

[ii] [https://github.com/G-Levine](https://github.com/G-Levine)

------
bitwize
So will they build a super-inexpensive, Christmas-present version around an
Arduino and call it the Pupperino?

------
ngcc_hk
Give them sensor it would be a robot. But just remote control ... or have I
missed something.

------
kanwisher
Finally a cool project for lockdown. Definitely think I’m building this

------
amelius
What kind of control algorithms do they use for robots like these?

~~~
serf
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](https://www.youtube.com/watch?v=4MGZvcd0xxc)

------
aszantu
Someone pls build this for grannies
[https://twitter.com/aszantu/status/1257007725277597698?s=20](https://twitter.com/aszantu/status/1257007725277597698?s=20)

------
lukevp
Ah a perfect use for that routed carbon fiber I have laying around...

------
tomphoolery
This is SO COOL!

------
softwarejosh
should not be 600 those servos are pricey

~~~
NathanKau
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.

