A Warning to Human Players During Autonomous

[The Lucas]

Human Players should stand firmly on their pressure pads and avoid shifting their weight during Autonomous Mode. Any movement could cause the pressure pad to switch off and disable your robot. This could have disastrous effects on your autonomous routine. To test what actions will turn your pressure pad off, watch your green light on the end of the alliance station and shift your weight to see if it turns off.

My team has a very consistent autonomous routine that we ran in every match at the Pittsburg Regional. We did not change this routine on Friday or Saturday of the competition.

During a few matches, our autonomous routine stopped half way through the routine and our robot was disabled (indicated by a solid disabled LED on OI). We talked to the IFI guy about this and he suspected our OI might be faulty. We decided we would replace it if we ever had the problem again.

We did have the problem again in the second quarterfinal match. This time the robot stopped half way through the routine and started running a different routine that got our robot stuck in a goal. Luckily, 869 and 808 won the match for our alliance so we had had time before the semifinals to diagnose the problem.

Our autonomous routine is selected by rotary (analog) switches. The routine that ran our bot into the goal in the second half of the autonomous period is the same routine that would run if our rotary switches were set to 127 and 127 (Note: during the autonomous period, the OI transmits 127's for all analog values and 0's for all digital values). It seems the robot got temporarily disabled and read in 127's into the autonomous selection variables, then ran that routine when it reentered autonomous mode. This leads me to this warning for programmers:

If you use switches on the OI to set autonomous routines, make sure the all 127's or all 0's routine is a "do nothing" routine.

We borrowed an OI from Spare Parts and swapped it with our OI. While we were queuing up for our next match, the IFI guy told us that he thought that our pressure pad might be responsible for the disabling. This makes sense because our human player is very light and might lean toward the field to watch our autonomous routine (especially the "tetra catching" part that is always entertaining). Before the next match, we tested this by watching the green light on the end of the alliance station that indicates the state of the pressure pad (“on” indicates a human player is on the pad). Sure enough, if our human player stood on the pad and leaned toward the field, the light would turn off.

We didn't have this problem again, so I pretty sure that this human player/pressure pad interaction is the cause of our problem. It could have been a faulty OI, since we did change the OI, but that seems unlikely. We will reuse the old suspect OI in future competitions (the other OI was a loaner).

So please warn all human players and programmers out there about this potential problem.