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  • In base or not?

    My kids have a new arm that may hang slightly out of base when they hit the EV3 button to launch if they forget to lift it by hand, but the first thing their program does is lift it -- before their robot moves -- so it is always in base before their robot leaves base or even moves. In base or not?

    We've read D03 and R13 carefully.

    Still, the kid's argument is that the robot doesn't GO (move) until after the arm is lifted by their program. I suggested that since hitting the EV3 button started the program that will make it GO (move) it may not be considered in base when launched because it wasn't in a READY SITUATION. They said they saw a team that they thought just had a timer between missions and they never did anything to make it GO, so is that not a launch? A timer made it GO, so in their (our) case, a timer (waiting for the arm) makes it GO, too -- after the arm is up. I'm still too rookie to reason with 10 year olds.

    (If this post is truncated like the last two, I give up.)
    scoTT

  • #2
    I'd say that's an illegal launch. And it's an easy call, R13 is very clear on this. Movement is not required for a launch.

    The robot is considered to be launched after "touch a button or signal a sensor" - not when the robot starts moving. At the moment of the launch, the entire robot must be completely In Base.
    FIRST LEGO League Mentor and Referee/Head Referee since 2011.

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    • #3
      Note: posts get truncated when you try to include text that was copied-and-pasted from a PDF file.
      FIRST LEGO League Mentor and Referee/Head Referee since 2011.

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      • #4
        It is an interesting debate regarding how a purely timer-based mechanisms are ruled. Typically the discussion involves an "interruption" due to "interacting with the robot". So if the robot drives back to base, then pauses while the team loads or unloads some objects, that would be an "interaction", and the robot was Interrupted. Then it must be re-launched (requires another button press or sensor activation). But if instead the robot simply drives away based on its timer and continues out onto the field, carrying some new payloads, none of those accomplishments would count because the robot wasn't launched.

        The debate then continues with whether the timer is considered a sensor.

        Then we rapidly start counting how many angels can dance on the top of a minifig, and chaos ensues.
        FIRST LEGO League Mentor and Referee/Head Referee since 2011.

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        • #5
          I don't think there is any debate about the timer being a sensor. It is clearly a sensor because it measures time. The debate is if waiting for time to expire qualifies as signaling a sensor. I don't think there's much debate here either. When a timer expires is not influenced at all by anything I do, so I cannot "signal" a timer.

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          • #6
            As a workaround, how about having a color sensor and using a sheet of black paper somewhere. Place the black paper under the color sensor, press start on the robot and wait for it to engage all the mechanisms, then remove the black paper as the signal for the actual start?

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            • #7
              Interesting. So, they need two button presses? One to lift the arm while touching the robot so it's not in a READY SITUATION, and press the button again when READY to GO. If that's not good, I guess technically, starting their sequencer in base before the match would be illegal by this logic, too. I think I'll pose this to our state ref.
              scoTT

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              • #8
                Originally posted by ssm View Post
                As a workaround, how about having a color sensor and using a sheet of black paper somewhere. Place the black paper under the color sensor, press start on the robot and wait for it to engage all the mechanisms, then remove the black paper as the signal for the actual start?
                Pressing "start" would Launch the robot.
                Removing the black paper would then Interrupt it again, because you've "interacted" with the robot.
                FIRST LEGO League Mentor and Referee/Head Referee since 2011.

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                • #9
                  Originally posted by winklestork View Post
                  Interesting. So, they need two button presses? One to lift the arm while touching the robot so it's not in a READY SITUATION, and press the button again when READY to GO. If that's not good, I guess technically, starting their sequencer in base before the match would be illegal by this logic, too. I think I'll pose this to our state ref.
                  What is required is that the entire Robot be In-Base when the robot is Launched.
                  Last edited by Tom Mosher; 12-28-2017, 01:57 PM.
                  FIRST LEGO League Mentor and Referee/Head Referee since 2011.

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                  • #10
                    Originally posted by winklestork View Post
                    Interesting. So, they need two button presses? One to lift the arm while touching the robot so it's not in a READY SITUATION, and press the button again when READY to GO. If that's not good, I guess technically, starting their sequencer in base before the match would be illegal by this logic, too. I think I'll pose this to our state ref.
                    Is the robot allowed to be running a program while it is Interrupted and sitting in Base? Sure, there's no rule against that.
                    Could that program assist with positioning the accessory arm and holding it in place while the robot is In-Base? Again, no problem with that. That's just part of the team's strategy for setting up their robot.

                    Best to mention it to the refs before the match so they don't misinterpret what the team is doing as part of setting up the robot.

                    FIRST LEGO League Mentor and Referee/Head Referee since 2011.

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                    • #11
                      On their mission that carries the Slingshot, they do something similar. When the robot returns to base, they hold an arm with a cage in position and hit a button to lock it, then they put the Slingshot in the cage to deliver it (it would be too heavy if the arm holding the case was not locked), and hit the button again to GO. I suspect that wouldn't be illegal because even if it would be considered an interruption, since it's wholly in base, no penalty. It seems I've read dialog here about starting sequencers but can't find it. Would a sequencer have to be started before they approached the table?
                      scoTT

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                      • #12
                        Tom, you answered again while I was typing. I think I can convince the kids that I'm right, the rule is clear, and they have to come up with another solution and see if they come up with two button presses or some other solution.
                        scoTT

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                        • #13
                          Originally posted by winklestork View Post
                          On their mission that carries the Slingshot, they do something similar. When the robot returns to base, they hold an arm with a cage in position and hit a button to lock it, then they put the Slingshot in the cage to deliver it (it would be too heavy if the arm holding the case was not locked), and hit the button again to GO. I suspect that wouldn't be illegal because even if it would be considered an interruption, since it's wholly in base, no penalty. It seems I've read dialog here about starting sequencers but can't find it. Would a sequencer have to be started before they approached the table?
                          Nothing that happens with the robot before the match starts is of any consequence. If teams are using a sequencer, typically it's already running on the robot before they arrive at the table and put the robot down in Base. Teams can start running programs at any time - as long as the refs aren't inspecting the robots to be sure that Bluetooth is disabled.

                          The tricky bit about interrupting the robot while it's in Base is that you can create an endless circle - launch the robot, interrupt it, re-launch, interrupt again, etc. The robot never leaves Base because the team has to keep re-launching it. This of course would only happen if the team brings a strategy with them to the table that the refs think causes this endless-loop situation.
                          FIRST LEGO League Mentor and Referee/Head Referee since 2011.

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                          • #14
                            Originally posted by Tom Mosher View Post

                            Pressing "start" would Launch the robot.
                            Removing the black paper would then Interrupt it again, because you've "interacted" with the robot.
                            Pressing a button is one way to signal a sensor and can thus be used to launch a robot, but pressing a button does not mean I launched my robot. I might write a program to raise the front attachment and wait for a button press. In this case pressing the start button does not launch the robot, it only starts a program. The launch action is the second button press. In ssm's example starting the program is not a launch. It just starts the program running. The launch is performed by removing the paper from under the sensor (actually it cannot be paper because everything you use in the game must be LEGO).

                            Launching requires action and intent. Nothing is a launch unless it is intended to be a launch. It's like baseball signals. You can do dozens of things to the robot while it is in base, including pushing buttons and interacting with sensors. None of these actions constitute a launch until the robot is ready and you perform the action intended to launch the robot.

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                            • #15
                              Originally posted by Tom Mosher View Post

                              Pressing "start" would Launch the robot.
                              Removing the black paper would then Interrupt it again, because you've "interacted" with the robot.
                              Upon further review, this might be OK, if the team tells the refs that that first 'start' press is just part of the robot setup process, and the "Launch" is when the paper is removed.
                              FIRST LEGO League Mentor and Referee/Head Referee since 2011.

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