
Show HN: Open-source quadruped robot with robotic arm - nicrusso7
https://github.com/nicrusso7/rex-gym#robotic-arm
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mike4921
This is the perfect opportunity to pitch my own version of this robot!
Implemented in a ROS framework, with a working walking gait, and some decent
documentation:
[https://github.com/mike4192/spotMicro](https://github.com/mike4192/spotMicro)

I stumbled on nicrusso7's github page as I was doing my own initial research.
I initially, naively, thought I could easily expand on his work and
reinforcement learn my way to a working walking gait pretty quickly. However
once I got a feel for the hardware and it's performance limits and the play in
the system, I realized differences between the simulated model and real life
would be significant, and would make debugging the translation from simulation
to real life difficult. Also I'm teaching myself software development and
reinforcement learning was another whole thing to learn.

So instead I took a different approach and implemented a more "conventional"
gait, with inspiration and examples from other similar projects.

I've abandoned reinforcement learning for now, as I'm more interested in
implementing mapping and motion planning going forward. But one day I'd like
to revisit it and see how the pipeline for ML to real implementation works for
something like this low level control.

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nicrusso7
Well done! Btw I do agree with you regarding the knowledge transfer on the
real robot platform. The open source design is built to work with very cheap
servos and the alinement is not quite easy too.

As you, I was totally new to RL when I started (almost 1 year ago) - I’m a
DevOps engineer during the day :) The goal of this project for me is learning
ML more than build a product - that’s why the limited focus on hw
implementation. Anyway, there are examples on the web on how to run the
policies on the real world robot (even using ROS) - maybe in the future I’ll
digging in this topic as well!

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vwat
Reading the comments it struck me: why is tele operated agricultural robots
not a thing? A robot with wheels and an array of cameras and arms. It rolls
down the line and remote workers pick the fruit. Maybe even out of country
workers being paid pennies...I’m sure the latency could be overcome. You could
host thousands of humans with very few robots. Better productivity, lower cost
in the long run and you’re resilient against labor problems which is really
good when all your labor is illegal. If nobody gives a good reason why it
doesn’t exist I would be receptive to people who might want to do a start
up...

Googling around I find some recent stuff. It seems to have started being on
people’s minds in the past five years only. A lot of complicated articulated
arms and inputs. I am only more convinced that there is arbitrage here... a
very simple articulation mechanism, something akin to what hello robot did vs
willow garage, would be totally new. And you don’t have to replicate perfectly
the performance of humans because it’s a sliding scale, you could use the
robot to downsize at first, following it with a small human team.

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jcims
Depends on what you’re harvesting but the challenges are likely to be in the
actual picking motion not dropping/bruising/cutting the food, if there is any
selection happening the senses of touch and smell are largely gone, navigating
the plant without damaging it, not compacting the soil around the roots more
than necessary, overall speed, etc.

Bespoke harvesters for things like potatoes and almonds obviously destroy
humans in the productivity department. If we’re still picking it that’s a good
signal that automation will be tricky.

We probably have the technology to do most of it now, but you may wind up with
a half million dollar robot.

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ptsneves
I have been fantasizing about a similar setup for some time, but an arachnid
instead of a quadrupod. I imagined it to pick up trash in land with a lot of
vegetation. Never got around it because I am on my own personal project and
this sounds like a massive amount of work for a single person. Congrats and
good luck. Will bookmark it so I can get back to it when I am freer. Sounds
like a very good starting point for this topic.

One thing, why use a machine learning algorithm for path finding in the maze
instead of just using an actual path finding algo? Did I miss something?

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nicrusso7
thank you very much! any feedback is welcome!

Re the maze, I've got just the terrain so far - I'm working on the gym
environment.. I was thinking to write 2 different versions of it, one in which
the robot has a map of the maze and navigate it using a path finding algo
(probably A*) and another version without any map (I'll probably need a lidar
for this).

~~~
ptsneves
Some time ago I tried to use rt-rrt[1]. It should be quite suited for your
setup, or at least more than A* i think. Actually when I get back to your
project I will try to implement it inside your framework.

[1] [https://github.com/ptsneves/rt-rrt](https://github.com/ptsneves/rt-rrt)

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nicrusso7
Awesome! Any PR is welcome. In the meanwhile I’ll have a look at your rt-rrt
implementation.

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hkt
I've been looking for an open source robovac for ages. This will definitely
do.

(Obviously this isn't very serious. I do however think this project is great)

~~~
nicrusso7
Oh well I can definitely add a vac-env on my todo list :D

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xVedun
This looks very cool! I wonder how close it is to the method that Boston
Dynamics uses to control the their version. Did they simply train a machine
learning algorithm for way longer than a hobbyist can or is there a ton of
manual tweaking?

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gene-h
Boston Dynamics probably does some form of force control. That is controlling
the force applied to the ground by the legs in addition to just the position
the leg is moving. The actuators here appear to be purely position controlled.

~~~
nicrusso7
yeah the current motor model takes the desired position as input and convert
it to torque (applying some 'noise' trying mimic the real motors).

