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EXPERIMENTAL ROBOT PLATFORM (ERP)

Updates:
June, 2007: v1a - Concept
February, 2008: v1b - Upgrade
March, 2008: v1c - Changes
April, 2008: v1c - Vision and Suspension

The Experimental Robot Platform
The goal of this robot is to give me a platform that is upgradeable and customizable so that I would not need to build a new robot chassis for each new idea I want to try out. This robot will never be 'finished', as I'm always modifying and improving it. I'll post here after each new major change I make.

As such, I will be slowly documenting the major changes I make to this robot over time. You make also keep up with the details and see more pics of the project on this forum post.


June, 2007: Concept of ERP Created, v1a
I first got my idea for the ERP in May to create a new 'ultimate' robot. I tend to do this every two years or so, my previous one being Taurus 2. Originally I wanted to call it Taurus III, for hopefully obvious reasons, but not much later I changed the name to ERP.

This below CAD video demonstrates what I originally wanted: a pan/tilt camera, wireless data transfer, and a basic differential drive.

But I quickly decided that this was boring, and the robot needed the ability to interact more with it's surroundings. This is where I decided to add a robot arm, optimizing it using finite element analysis to keep the weight low but the strength high:



For electronics I decided to use my custom $50 Robot controller, the CMUcam, a Sharp IR, and a pen laser (for pointing, duh).

This is an early test of the ERP's low-level functions:

As its legacy, this robot is what inspired me and was used to write my UART tutorial, bootloader tutorial, and cycle timing tutorial. I also used it to get bluetooth and RS232 working to transfer data.



I never went much further than that for this version, but here is my source code (as is) for anyone else interested in taking it further:
ERP source code for $50 Robot controller




February, 2008: ERP Gets Upgraded, v1b
Tons of time had passed between the previous version and this one. The main reason is that I wanted to control more hardware, and so I needed a controller with tons of new capabilities. Hence I spent tons of my time working on my Axon microcontroller. I also added a much better battery, and tons more space for future upgrades of electronics/sensors/etc.



And of course, I wanted hands on two arms that can grab stuff. At this time I was just making a hand on one of the arms - when I'm satisfied with the design, I'll put it on both.



I've been asked on several occasions if I built this using a kit . . . NO!!! Everything was custom made from 'scratch', with the exception of the CMUcam. I designed the whole thing in CAD, and used a CNC to produce the parts.



This video shows the only interesting test I ran:


March, 2008: ERP Changes, v1c
Since v1b, I've looked into all the problems it had and fixed them all.

The first problem was that my custom wheels were too smooth, resulting in too little traction. In v1b, I needed really thin yet wide diameter wheels. I couldn't find any to buy, so I ended up making my own using a CNC. This is what they look like:

So to fix that smoothness problem, I just so happened to have a large sheet of rubber stuff from mcmaster.com with a sticky backing on the other end. Rolling it up, I cut slices into it using a bandsaw. I tried scissors but it didn't work very well . . .



Then pealing off the sticky backing, I slowly rolled the slice around the diameter of the wheel. I used scissors to clean it up. It works really nicely now:



In other news, I made a strategic partnership with Surveyor Corp. We are trying to integrate the Blackfin Robot Camera with my Axon microcontroller, and since I never really liked the CMUcam anyway, now is the perfect opportunity!

Here are some new CAD images with a few of the changes I made - integrating the new cam, improving the gripper, and adding a second caster wheel to improve balance.






March, 2008: Vision and Suspension, v1c
More will be reported soon, but for now, enjoy this video of ERP doing vision at MOBOT 2008:

ERP (team Pikachu) won judges choice:
"Initially we awarded the judges' choice to Megubot to reward a good effort and to encourage participation of young "engineers" like Megan McKelvey. After seeing the presention on Pikachu and fully appreciating the level of effort and extrodinary engineering that went into it, we felt it imperative to reward that effort with a second Judges' Choice award."
- Ben (for the Mobot Committee)

The score:


To learn more about the MOBOT competition and see more videos of it, visit the MOBOT tutorial. See pics of me and Pikachu (ERP) at c|net's news.com MOBOT 2008 coverage - I'm on page 6 and 11, wearing all white. You can also read about it on CMU's official news paper, The Tartan. And more official MOBOT 2008 photos.

Come back later, I will be posting more here soon!