18 Jun 2003 lnxfergy   » (Master)

First Entry

Hey, this is my first entry into my diary. Currently I am working on my new multipurpose robot. It will be the Little Green Machine Two.

The original Little Green Machine was disassembled after it suffered many design flaws. I thought I would go through those failures, and explain some things I picked up along the way.

First off, it turns out that modified servo motors aren't as good as some people say they are, especially under constant running (they are really only suited for a very light robot that won't being running for a while at a time). As they get hot, the RC circuit inside is thrown off, and the timing gets messed up. This means that if you calibrated the motors to have stop in the middle, they will actually rotate when you think they are stopped. Go for broke and buy gear motors with encoders, that is what I am doing for the new robot.

The other problem I had was suspension. The old robot didn't have any and would often get hung up, the new one has suspension on the casters. I am using those little RC air shocks - they are slightly expensive but are smoother than coil springs - and look really cool.

The new robot also has a more powerful, more reliable controller. I was using a Dios - kindof like a basic stamp only bigger, faster and cheaper - from Kronos Robotics (www.kronosrobotics.com) and although I did love the chip, I have to upgrade. The chips are a great learning tool, but I want a C compiler.

Anyways, thats my motivation for designing the new robot and a little bit about the old one. I will post more details as I go along. Right now I am working on getting AVR-GCC customized and ready to go and designing the boards - then its on to making a bootloader and designing the motor controller.

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