Difference between revisions of "Talk:DEWBOT X Midknight Mayhem"

Revision as of 12:28, 1 July 2014

During the mentors' matches, Douglas noticed that the drive train was not working correctly. He suspected a pivot out of calibration. Robot would not drive straight.

We checked this back in the pit and what we observed was:

1. The wheel treads on the robot's left side are completely worn. The right side treads are not nearly so worn (both were changed at the same time: at FRC Championships)
2. In crab drive, everything looks normal. Left front wheel starts driving a bit later than the rest, but angles and drive directions look okay.
3. In ocelot, we some drive angles that don't seem to make any sense.

The differential wear suggests we have wheels fighting each other as we drive, most likely due to incorrect angle. This would also explain the not driving straight complaint.

This could also tie into the low drive speed issue. We need more data.

Drive Speed Issue

Which checking drive speed with video on 14-June, I discovered that DEWBOT X's top speed was no more than 6 ft/s (avg = 5.6 ft/s; std dev = 0.5 ft/s; n = 9). It should be about 9 ft/s.

If drive-train frictional forces were causing this speed reduction, each of our CIMS would be drawing about 60 amps and the 40 amp breakers (not to mention the 100 amp main breaker) would be tripping constantly. They are not.

Action List for 2-July meeting

• Video each pivot wheel for speed determination at 120 or 240 fps (Use GoPro Black) - determine rotational speed for each wheel for each test
  • Robot on blocks - driven by on-board control at top speed
  • Robot on blocks - driven by PWM tester at top speed
  • Robot driving straight ahead top speed (joystick straight ahead w/out correction)
  • Robot driving straight ahead top speed (correcting to maintain course)
• With robot on back, simultaneously video robot bottom and x-box controller to have linked video of control input and wheel angle output - high quality video needed here - 30 or 60 fps 1080p