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.

[Andy A.]

Thanks for the heads up!

I'll pass that along to our programmer.

I've never liked the pressure pads. This just confirms my suspicions: Pressure pads hate robots. It must be some inferiority complex or something.

-Andy A.

[Alex Pelan]

Also keep in mind that there is a penalty if you leave the pad during autonomous. I did some testing of my own at UTC in the matches that I human played, and I found, even with one foot in and one foot out of the pressure pad, the green light was still lit. Thus, I got the impression that they were more forgiving than what has been described here. Anyone else notice how much pressure was needed to power on the pressure pads?

[KenWittlief]

dont jump up and down in your excitment :^)

[Wetzel]

Originally Posted by KenWittlief

dont jump up and down in your excitment :^)

I saw this at least once durring VCU.

Wetzel

[Jack Jones]

Originally Posted by Alex Pelan

Also keep in mind that there is a penalty if you leave the pad during autonomous. I did some testing of my own at UTC in the matches that I human played, and I found, even with one foot in and one foot out of the pressure pad, the green light was still lit. Thus, I got the impression that they were more forgiving than what has been described here. Anyone else notice how much pressure was needed to power on the pressure pads?

It's a 30 point penalty

[KTorak]

Human players are also not allowed to touch/grasp/hold a tetra in anyway until the autonomous period has ended.

[meiv4]

once at the Sac regional one humal player was running back to the pad and he tripped so as he fell he kinda launched himself at his pad and barly got his hand on it, but it didnt register, it sure was a valient effort though.

[eugenebrooks]

Originally Posted by 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.

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 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.

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

If you are using the switches on the OI to select the autonomous mode, you should read and save the values while the robot is disabled, and write code that sets a flag to stop saving the value once the robot has been enabled. That way, a spurious disable will not affect the autonomous mode.

It is interesting that the human player on the pad can communicate with the robot by shifting his/her weight on the pad. I am sure that FIRST did not intend this. We use a set of switches on the robot to select the autonomous mode in binary. Values set by these switches are not affected by the disabled state...

[The Lucas]

Originally Posted by eugenebrooks

If you are using the switches on the OI to select the autonomous mode, you should read and save the values while the robot is disabled, and write code that sets a flag to stop saving the value once the robot has been enabled. That way, a spurious disable will not affect the autonomous mode.

It is interesting that the human player on the pad can communicate with the robot by shifting his/her weight on the pad. I am sure that FIRST did not intend this. We use a set of switches on the robot to select the autonomous mode in binary. Values set by these switches are not affected by the disabled state...

Another way to make sure the routine selected on the OI is not changed during a spurious disable (autonomous_mode and disabled_mode both = 1) is to set the auto select variables if not in autonomous mode like such:

if(!autonomous_mode){
//set auto select variables
}

However, this may result in certain variables (step, gyro, encoder, coordinate, integral, etc..) being reset or incorrectly changed, depending on your code. If that is the case, your robot would likely restart the same routine at a different starting point or go haywire in some another way.

I personally would prefer to just cut bait and sit out the rest of the 15 sec with a "do nothing routine", than risk getting stuck in a goal again. We were lucky to win that quarter final match. We were stuck for nearly the entire match and committed a 10 point penalty, but 869 and 808 overcame all that and won it for the alliance.

[eugenebrooks]

Originally Posted by The Lucas

I personally would prefer to just cut bait and sit out the rest of the 15 sec with a "do nothing routine", than risk getting stuck in a goal again. We were lucky to win that quarter final match. We were stuck for nearly the entire match and committed a 10 point penalty, but 869 and 808 overcame all that and won it for the alliance.

Are you intending that a momentary lift on the human player
pad change the autonomous program that is selected after the
match starts?

[DarMagi]

We never had a problem with the pressure pad or our human player on the pressure pad, although we didn't have any purposeful auton modes except go to the human loading zone and fun acress the field into other bots but besides that, the pressure pad fine, we never once lost power to our bot, although an OI at the competiton did give us problems in one of the stations... that's another story... Also be careful to not touch any tetras until the auton period is over, that is when the signal goes off and not when the clock resets to 120. Our human player grabbed a tetra when the clock hit 120 seconds after the 15 second auton, but the signal did not go off until 119 seconds left, with that we got one 10 point penalty for touching a tetra while in auton mode. So my warning to all teams is to not touch tetras until the buzzer goes off and the drivers are able to step forward and drive their bots. Penalties are bad, don't get hit with them for things like that.

[The Lucas]

Originally Posted by eugenebrooks

Are you intending that a momentary lift on the human player
pad change the autonomous program that is selected after the
match starts?

No, I am not saying you should use this to change your autonomous in order to find a vision tetra or anything like that. I am saying that a momentary disable (from the human player pressure pad) would likely mess up any autonomous routine and may change to a different routine (one selected by all 127s or all 0s coming out of the operator interface) depending on how you select your routine. Most teams who have selector switches have a "do nothing" setting. I am simply suggesting that programmers make this "do nothing" the same as all 127s or all 0s, which is the output during autonomous mode and also the output if the switches fail. Obviously, everyone's autonomous code is different and will react differently to a disable, but it doesn't hurt to make all 127s or all 0s a "do nothing" setting.

Originally Posted by Alex Pelan

I did some testing of my own at UTC in the matches that I human played, and I found, even with one foot in and one foot out of the pressure pad, the green light was still lit. Thus, I got the impression that they were more forgiving than what has been described here. Anyone else notice how much pressure was needed to power on the pressure pads?

I am not saying problems with the pressure pad are at all common. I didn't even figure this one out myself, the IFI guy suggested the pressure pad disable was the cause of our problem and I agree with him. As I said before, our human player is very light, around 110 lbs (Alex you will see him at Philly).

We had this problem and I am trying to warn others about this potential problem. It was a very frustrating problem to diagnose, especially since you can't simulate the controllers and pressure pads on the field with a simple dongle box (it still sends OI data in autonomous, so you could even drive the robot with a joystick if you wanted). If everyone is aware of this potential problem, it doesn't take much to prevent it from ever happening again.

[C. Morrison]

Is there a weight requirement for the pressure pads to remain active?

[Validius]

i dont know how much wieght you need. all our HPs are 150+ pounds