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Space Travel: Any problems during qualifiers?

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  • Space Travel: Any problems during qualifiers?

    I'm wondering if anyone has seen problems with the Space Travel ramp during their qualifiers or practices? Have the carts been rolling down the ramp ok? (assuming they've been properly placed, of course).

    The carts are very sensitive to small changes in the wheel/tire alignment. I can foresee cases where the cart starts rolling out of a fully raised orange ramp but grinds to a halt prior to reaching the first track connection.

  • #2
    The standard guidance is for the referees to occasionally lightly roll the payloads across the mat while applying light pressure. This keeps the wheels aligned and free-rolling.
    FIRST LEGO League Mentor and Referee/Head Referee since 2011.

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    • #3
      On our last game run at last Saturday's qualifier, the ref checked the first payload to make sure it would roll freely. If you are nervous about this, I suggest having a team member ask a ref to do this.

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      • #4
        Yep. We had a cart not roll on Saturday. We had a passive attachment that lifted the ramp, but it didn't go. The kid ran it over and over (it took about 4 seconds) and finally gave up. The ref tilted it at the end of the match and it didn't move. They gave us the 22 points.

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        • #5
          We found that wheels get pinched together by the Lego pieces on the outside and do not allow cart to roll. We are going to ask ref to check them, to make sure that they roll freely. Remedy is to slightly push Lego pieces away, it make a huge different in how cart rolls!

          It is, by far, my least favorite (inconsistent) mission this year!
          Last edited by Leon R; 11-25-2018, 12:13 AM.
          Legolympians - 2009-2015 (retired - joined FRC team 5422 Stormgears)
          Legolicious - 5th year girls team
          Brick Force - 2nd year boys team

          2015 - Mass FLL coach of the year.

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          • #6
            Just like in NASA, you have to add that to the pre-launch checklist!
            Coach, FLL Team 3146 Peace By Piece 2013 - 2016; Team 29410 The Dragon Bots 2016-2018
            Judge, FTC 2014-2015; Field Technical Advisor, FTC 2016-2018; Robot Inspector, FRC 2018

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            • #7
              Originally posted by Leon R View Post
              We found that wheels get pinched together by the Lego pieces on the outside and do not allow cart to roll. We are going to ask ref to check them, to make sure that they roll freely. Remedy is to slightly push Lego pieces away, it make a huge different in how cart rolls!

              It is, by far, my least favorite (inconsistent) mission this year!
              I have seen this be the cause of the cart not rolling on several different fields. Once the wheels were pushed apart, the carts all rolled freely.

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              • #8
                I don't think I would waste much thought on checking the wheels UNLESS the payload not rolling down the ramp has some negative effect on the mission. If the payload doesn't roll down the ramp because the wheels are sticking you will be awarded points for the mission. I would occasionally practice the mission with the wheels intentionally pinched so the team is prepared for when the mission model fails as opposed to the mission failing. Was that a good ramp lift? If the lift was good but the payload didn't roll down the ramp continue on to the next mission, even if the next mission drops two more payloads on the stuck payload. When missions fail because the field model is messed up teams get benefit of the doubt. You are not punished for expected wear and tear.
                Last edited by Dean Hystad; 11-26-2018, 05:05 PM.

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                • #9
                  Originally posted by Dean Hystad View Post
                  You are not punished for expected wear and tare.
                  Or poor mission model design?

                  Originally posted by Dean Hystad View Post
                  If the lift was good but the payload didn't roll down the ramp continue on to the next mission, even if the next mission drops two more payloads on the stuck payload. When missions fail because the field model is messed up teams get benefit of the doubt.
                  If we get the benefit of the doubt then I'm rooting for the first cart to get stuck immediately. Then we'll be awarded full points for just attempting to place the other two?

                  I'm being facetious, of course. I hope the models work as intended and good designs rewarded appropriately. We'll ask the refs to check beforehand so as to not count on their generosity in the event they get stuck.

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                  • #10
                    Originally posted by rcatarella View Post
                    Or poor mission model design?



                    If we get the benefit of the doubt then I'm rooting for the first cart to get stuck immediately. Then we'll be awarded full points for just attempting to place the other two?

                    I'm being facetious, of course. I hope the models work as intended and good designs rewarded appropriately. We'll ask the refs to check beforehand so as to not count on their generosity in the event they get stuck.
                    I think the design is fine. If LEGO had a slightly larger wheel I'm sure they would have left off the rubber tire and all the problems would go away. Back in the RCX days the ramp would be made of studded technic beams with plates and tiles to get the spacing right.

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                    • #11
                      Originally posted by Dean Hystad View Post
                      I think the design is fine.
                      Agree to disagree on this one. We wouldn't consider it good design if a team's robot only worked if the wheels were tweaked just right and if bumping them slightly took them out of alignment.

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                      • #12
                        Agree to disagree on the challenge at hand. (I do get your point and frustration...) But another way to look at it like this - the challenge set of the same for everyone since day 1. Real life does not have perfect wheels and perfect alignments. The challenge is to get a robot (and team) to perform well even when things are not perfect. But to root for failure so you can gain advantage in future efforts, doesn't seem a great pathway to work along.

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                        • #13
                          Originally posted by dna1990 View Post
                          Agree to disagree on the challenge at hand. (I do get your point and frustration...) But another way to look at it like this - the challenge set of the same for everyone since day 1. Real life does not have perfect wheels and perfect alignments. The challenge is to get a robot (and team) to perform well even when things are not perfect. But to root for failure so you can gain advantage in future efforts, doesn't seem a great pathway to work along.
                          I don't think anyone is rooting for failure. This is a model with a well known, frequently occurring failure. Teams should know what to do in case the model doesn't work correctly. You should not replay the transit mission over and over if the payload doesn't roll down the ramp when the ramp is clearly tilted high enough that the payload should roll. Teams should also not throw away additional payload points just because the initial payload failed to roll down the ramp. The only way to know what to do is simulate (or force) the failure and prepare a contingency for when things don't work.

                          Refs and table setters will do their best to have the payloads working properly. You can count on everything working fine, or you can be prepared. To me this is just like a sensor or odometry or any other thing you encounter in the game. Sometimes things don't work like you want and you have the choice to do nothing but complain, or you can solve the problem.
                          Last edited by Dean Hystad; 11-26-2018, 07:08 PM.

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                          • #14
                            Originally posted by Dean Hystad View Post
                            I don't think I would waste much thought on checking the wheels UNLESS the payload not rolling down the ramp has some negative effect on the mission. If the payload doesn't roll down the ramp because the wheels are sticking you will be awarded points for the mission. I would occasionally practice the mission with the wheels intentionally pinched so the team is prepared for when the mission model fails as opposed to the mission failing. Was that a good ramp lift? If the lift was good but the payload didn't roll down the ramp continue on to the next mission, even if the next mission drops two more payloads on the stuck payload. When missions fail because the field model is messed up teams get benefit of the doubt. You are not punished for expected wear and tear.

                            Originally posted by dna1990 View Post
                            Agree to disagree on the challenge at hand. (I do get your point and frustration...) But another way to look at it like this - the challenge set of the same for everyone since day 1. Real life does not have perfect wheels and perfect alignments. The challenge is to get a robot (and team) to perform well even when things are not perfect. But to root for failure so you can gain advantage in future efforts, doesn't seem a great pathway to work along.
                            So as Head Referee this coming weekend, should I just take a laissez faire attitude towards all the field setup kits that teams are lending for the competition and disregard mission models that are obviously built wrong (or are just missing) and just give the benefit of the doubt to teams left and right?

                            There has to be some bounds on what variations should be expected. We typically spend around 2 hours to get all the fields working right before the robot game matches. I don't see what the problem is with having the field reset people make sure the field works as intended since it makes for a much better show. It doesn't seem that teams would be inspired when their robot fails because the field wasn't built right, even if they do get the points anyway.

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                            • #15
                              Originally posted by philso View Post




                              So as Head Referee this coming weekend, should I just take a laissez faire attitude towards all the field setup kits that teams are lending for the competition and disregard mission models that are obviously built wrong (or are just missing) and just give the benefit of the doubt to teams left and right?

                              There has to be some bounds on what variations should be expected. We typically spend around 2 hours to get all the fields working right before the robot game matches. I don't see what the problem is with having the field reset people make sure the field works as intended since it makes for a much better show. It doesn't seem that teams would be inspired when their robot fails because the field wasn't built right, even if they do get the points anyway.
                              As a team I wouldn't spend much time thinking about how the models are maintained. As ref or table setter I would give it a lot of thought. I'm saying that teams should be prepared for this failure (that is happening regardless of head ref diligence) instead of panicking. What are you going to do if the initial payload doesn't roll down the ramp? What are you going to do if additional payloads don't roll down the ramp? Trying to avoid the failure is well and good, but I've seen this problem pop up quite often, even when we aren't rough of the models and even after we did the spreading and the rolling and all the other tricks that are supposed to work.

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