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Mat Lifting up in Traffic Mission

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  • Mat Lifting up in Traffic Mission

    Is the mat supposed to be attached to the game table somehow? I have a student who is designing an attachment to lift the traffic obstacle and the mat is lifting up with the traffic. Any help is appreciated!

  • #2
    Found the relevant documentation:

    "When placing your Field on an Official Table, gently slide the Mat until it meets up against the South and East Border Walls. To hold the Mat in place, you may use a thin strip of black tape on the West edge as needed. Where the tape sticks to the Mat, it may cover the Mat

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    • #3
      The mats at your tournament may be taped down. I don't like depending on "may". I would rather design a solution that holds the mat down or doesn't depend on the mat staying down.

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      • #4
        That's a good point. Thanks!

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        • #5
          One of the tournaments that we attend use a spray adhesive on the bottom of the mat and table to hold them down. Another tournament we attend uses nothing. This can be bothersome as it can effect the way the robot runs. So, one of my boards is sprayed and one is not.

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          • #6
            I have never heard of spray adhesive on a mat. That's an interesting twist. The Table Overview directs that the Mat should be able to slide to the South and East Border walls.
            https://firstinspiresst01.blob.core....e-overview.pdf
            It only talks about tape on the West edge.

            We had a state kickoff this past Saturday and, in Illinois, there will be only the tape of the West edge.
            There is an ongoing discussion on whether that tape is part of Home or the Launch Area.
            I suggest you talk with the organizer of your regional qualifier and see what they intend to do.

            As to the original issue of the robot lifting the mat, you may want to work with the kids to design a solution that does not lift the mat. We had the same issue with the Into Orbit Strength mission model and the kids decided to hold the model and mat down while lifting. If your team's solution causes the mat to lift, can they use a beam or axle or some other part to hold the mat in place while lifting. This would be better than relying on how a mat is attached. Good Luck.
            FLL coach Trash Trek on, State 4x, World 2x, ref, judge advisor.

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            • #7
              It is ok to expect the table to be set up according to the rules, but you should do your best to never depend upon it. Blanche Dubois depended on the kindness of strangers and it didn't work out so well for her. Your robot should not depend on it either, even though FLL is full of kind and helpful folks.

              There are rules that describe how the mat is positioned on the table, and there are marks on the mat showing where all the models should be positioned, and the field setup guide describes how all the models should be configured at the start of the run. It is the job of tournament personnel to make these things right, but it is the team's job to make sure everything is right before they signal the referee they are ready to go. Checking everything every time is difficult. Sometimes you will miss something, and if that something makes the robot fail, there's not a lot you can do about it. The referee may award you missed points, but there is no guarantee of that in the rules.

              But do not despair. Even though the table may not always be perfect for each robot run, it is usually pretty close. If you design your solution to allow for common errors, your robot can make adjustments and have success. These are the most common errors/differences I see at tournaments. Feel free to add onto the list.

              1. The mat isn't always positioned correctly. This can add some navigation error if you only depend on walls or wheels (or even gyros) to know where the robot is. You can compensate by using marks or models that are attached to the mat, or using attachments and trajectories where 1/2" error either way doesn't matter.

              2. The mat is wavy and the waves mess up your light sensors. This can be fixed by having a shroud around the light sensor or placing the sensor near the wheels. The idea is having something that prevents the mat from pressing up against the light sensor. A shroud also makes your robot less sensitive to ambient light.

              3. There are creases in the mat or imperfections in the table that affect driving. To balance your robot will have casters or skies or some sort of sliding thing. Depending on their design some of these balancers are really sensitive to the smallest surface imperfection. Sometimes these imperfections are on your own table and their lack at the tournament causes problems (I had this with my 3 part portable table), or the roughness may be in the tournament tables. It is a good idea to create "artificial" roughness for testing purposes to see how it affects your robot. If a dime placed under the mat in a strategic place causes a mission to fail you might want to look at using a different balancer design. or maybe use some sensor feedback to correct for navigation errors that may occur between launch and the field models. You might design features into the robot or the attachments that help the robot align to the models.

              4. The walls are rough and they mess up my wall follower. A wall follower might work great at home, but fail miserably if it runs into a knothole or a warped wall board. Here again you can do some testing by taping a coin to the wall and seeing how well your robot handles the bump. Maybe you need a different interface between the robot and wall (wheel vs skid), or maybe you need to move the location of the wall following device.

              5. The tournament table walls are shorter/taller than our table at home. This bit one of my teams the year FLL changed the table design in the coach's handbook. The new coach built the new table with the new, shorter walls. The tournament still had 3.5" walls, and some wires that passed over the wall on our table bumped into the walls at the tournament. I have also heard stories about teams that had a wall follower designed for high walls that failed on the tournament table that had low walls. Know that there are old tables with taller walls and newer tables with shorter walls, and make your robot work for both. Hopefully this problem will become very uncommon soon.

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              • #8
                Originally posted by Belleview Robotics View Post
                One of the tournaments that we attend use a spray adhesive on the bottom of the mat and table to hold them down.
                That's really not allowed - and never has been that I know of.

                Bad move by your tournament organizer.
                FIRST LEGO League Mentor and Referee/Head Referee since 2011.

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                • #9
                  The first year I worked with FLL as a mentor/helper (years before I became a coach), the coach I worked with used a staple gun to attach the mat to the board... That doesn't seem to be within the rules now that I look back at it...

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                  • #10
                    Originally posted by Tim Carey View Post
                    The first year I worked with FLL as a mentor/helper (years before I became a coach), the coach I worked with used a staple gun to attach the mat to the board... That doesn't seem to be within the rules now that I look back at it...
                    I don't recall that being part of the field setup procedure.
                    FIRST LEGO League Mentor and Referee/Head Referee since 2011.

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