[archiver]

Posted by Dodd Stacy.

Engineer on team #95, Lebanon Robotics Team, from Lebanon High School and CRREL/CREARE.

Posted on 4/2/2000 4:13 PM MST


In Reply to: We Need Help!!!!!!! posted by Travis Covington on 4/2/2000 10:55 AM MST:



Have you tried to localize where the problem lies? Being a hopeless dummy about all things electrical, here's what I'd try:

1) With the gearboxes in your normal driving alignment, block up the chassis and turn over the wheels by hand (backdriving the motors), left side, right side, forward, backward. If they don't feel substantially different, you are probably free of driveline problems.

2) Swap the PWM inputs to the two speed controllers, left for right, and operate the bot under the conditions that cause you problems. It will steer backwards, but you can adjust to that. If the problem swaps sides, its cause is probably in the control code or in the communication link. Using the tether could assess the latter.

3) Swap the PWM inputs back where they belong, and then swap the speed controller outputs, left for right. Try again (still steering backwards). If the problem swaps sides, its cause lies between the battery +12V terminal strip and the speed controller (including connecting wiring).

4) If the problem DOESN'T swap sides in 3), then I'd suspect a wiring fault between the speed controller output and the motor on the bad side, maybe an intermittant short to ground through some chafed insulation, maybe aggravated during match interactions? You can check this by disconnecting the suspect wiring and temporarily jumpering from speed control output to motor on the bad side.

I apologize for suggesting the obvious, but I always screw up when I don't ask and answer the dumb question before looking for detailed explanations.

Good luck,
Dodd