Let's Make Robots!

Tiny Tim

Scripted driving for testing and finetuning motor control

This is my supposed entry for the 2010 DTU Robocup challenge. The body is made from LEGO Technic bricks from the Robotics Invention System (the old MINDSTORMS set) and from two 8287 Technic motors that are used in some of LEGO's R/C buggies. The electronics are homemade on a perforated board and basically consist of voltage regulation circuitry, two motor driver circuits and an ISP connection for programming the robot. Check out the schematic for more details.

mcu_0.png

The current video is where I test out how the robot drives - which it does kind of like Evil Knievel! This robot uses a new kind of skid-steering where the wheels fly right off the axles :-)

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Hey, how about a ramp for this? I'd like to see some jumps!

http://letsmakerobots.com/node/16405

I'm sorry frits, revenge won't bring Trata II back. You're just going to have to accept that he's gone to the big snowbank in the sky...
man that thing is fast!! arent you scared when it crashes with all that electronic stuff on it ?
No, I'm not scared. It has already taken quite a lot of beating and the worst thing that happened so far was that the MOSFETs got a little bent. Anyway this is a prototype so it's built to burn! :-)

wow! very fast little beast!!

Nice to see Lego Technics here  ;)

Wow I think this is the first robot I`ve seen that forcibly tries to disassemble itself. Maybe it had an itch it couldn`t reach!

I`m interested in the motor driver schematic. How does it work tying the gates together?  I thought that would just short the battery?

Well I'm not a professor on the subject of MOSFETs but I watched some video lectures from MIT's 6.002 electronics course where professor Agarwal pointed out that CMOS-logic works by tying the gates of the complementary MOSFETs together. I think maybe you'd have to make sure that the MOSFET threshold voltage and your supply voltage are within certain boundaries to avoid too much shoot-through (shorting the battery) but I'm really just guessing here.

Regarding the robot and the itch it succeeded in reaching it yesterday where it broke one of its wheels. The wheel hub broke when colliding with the leg of the couch :-).

Hey, that's a good challenge! A robot that takes itself apart!

Fast fck!

Looking forward to see it do line following at that speed!