[jaustin]

I'm attempting to implement Kevin Watson's 2005 Nav code on our EDU Mini controller to give my team a small scale platform to learn about PID contollers and to expirement with their own code. (this will be the first year we attempt to use encoders & gyros) I basically took the EDU code as written and added pid.c/h, robot.c/h, encoder.c/h, gyro.c/h, commands.h as well as adc.c/h. I updated the ISR's for adc & encoder.c. I have also updated all the constants to apply to the smaller bot. The software compiles and runs but I'm having a few problems.

1) I put CMD_GYRO_BIAS at the top of the list and it seems to work fine. However, it seems to go haywire after that. Sometimes it steps through my command list just fine and other times it jumps out of the loop to show "unknown command restarting ...". It's as if the rc variable is getting randomly set, and when it moves to the next command it does not recognize it (even thought it did the last time it ran). I've got the NULL command as the last one.

2) The PID algorythm does not really monitor the error between the left and right motor speeds and so the bot won't go straight. This is a known shortcomming and I've read all the posts and some friendly folks are helping with code examples to fix that. However, I can't even get the bot to go straight when contolling on velocity. No mater what setting (pwm value) I use, my left motors alway go faster than my right motors. I'm wondering if there is some inherant issue with either the EDU mini controller or the motors?

Any advice would be appreciated! Thanks folks!

Jeff Austin
Mentor - Team 372