OK! The blog is up, we just had our second class session, metal’s being cut, and simulations are being written. We’re off to a hell of a start, and now it’s time to tell the world.
We are Project Hexapod. We’re a team of 19 people who are trying to pull off the highly improbable; building a giant (1-2 ton, 15 foot diameter), rideable 6-legged hydraulic robot. We’re not some robotics company, and we’re not working off of some big grant or another. We’re tackling this problem in a whole new way; we’re a class based out of Artisan’s Asylum, a community workshop with all the fabrication facilities we could possibly need, where 15 students are learning how to build robots from 3 industry roboticists from Barrett Technologies and other local robotics companies, and 1 national champion Battlebots builder as a teaching assistant.
As I mentioned, we just had our second class session. The class officially kicked off on April 17th, though me, James and Dan have been working on the system-level design for the past 6 months to make sure the whole thing was possible. We’re going to push to make this project as open-source, publicly engaging and widely available as possible, so be sure to check this blog for presentations, source code, design documentation, the works.
And thus, without further ado, let’s talk classes!
Class 1: What Did We Get Ourselves Into?
Our first class was all about shock, awe, and expectation management. We introduced ourselves, the scope of the project, the exercises and design steps we would be taking to achieve our goals, and then did a quick introduction to hydraulic systems to get everyone on the same page. Once all of the lecturing was done, we broke up into a controls team and a mechanical team; the controls team busied themselves in setting up a simulation environment that James and Dan developed for the class, and the mechanical team got launched on making and welding parts together for the Leg Cart (more on that in a bit). You can check out our introductory presentation here: Rideable Hexapod Intro 2012-04-17
After the introductory presentation, I presented an introduction to hydraulic systems. If you’ve never used hydraulics before, I suggest checking this out – they’re a fascinating power transmission technology widely used in farming equipment, earthmoving equipment and high end robots like BigDog, but are almost nonexistent in the hobby/amateur robotics world. There’s certainly a steep learning curve to hydraulics, but hydraulic systems are awesome and you should learn how to use them. Learn more about them with us here: Intro to Hydraulics 2012-04-17 (Warning! There is one gory image of a hand after it’s been hit by a hydraulic leak, which may be NSFW)
Once all the presentations were over, it was time to start work on the Leg Cart! Also known as the Land Barge, Land Gondola, single leg prototype, that-which-cannot-be-stored-easily, and generally-terrible-idea. The mechanical team got a giant cut list to work on for the next two weeks, and the controls team got introductory exercises in our custom simulation environment.
The Leg Cart
The cart is a giant, 600 pound monstrosity with a half-scale hydraulic leg sticking out the side, a hydraulic power system (using a 100 pound field-wound electric motor attached to our hydraulic pump), all on four fixed casters (yeah… you heard us… we’re going full stupid here). The idea here is to have the students get familiar with working and welding steel, assemble a functional hydraulics system for the first time, wire real hardware with feedback sensors and a computational platform, wrap feedback loops around sensors and the hodge-podge hydraulics system we’ve assembled, and then control custom hydraulics hardware in closed-loop forward and inverse kinematics. If everything goes according to plan, the cart will be able to paddle its way up and down a section of the shop aisle.
OK. That’s the update for class 1. Stay tuned for the next class update, where we post some pictures about our progress on the Leg Cart and maybe a simulation video or two!