Announcement

Collapse
No announcement yet.

Push-able "Wall" Attachments

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Push-able "Wall" Attachments

    Does anyone have tips/tricks for creating the "wall" type attachments? This is where the robot starts in base and pushes what looks like wall towards the missions. There are enough gear linkages and passive attachments on the wall that it allows the robot to accomplish multiple missions at once and the wall usually gets left on the mat and does not return to base with the robot.

    My team has tried for 3 years in a row to build one and they never work! They don't go straight, and tend to turn because the robot is usually pushing from one side instead of the center of mass. I think it fails because the team usually ends up with a modified educator robot (which is rather narrow compared to most box robots), and its simply not wide enough to push a wall unless it is permanently attached to the robot. That said, the permanently attached wall attachments work great, tho they do tend to drift towards the center of mass.

    They have abandoned the idea for this year, but they asked me if they could work on them after the season ends, so I am on a mission to find some good building tips/tricks.

    Anyone have a good video or instructions? I think the kids are going to have fun tinkering, once the season ends, but we don't have time right now. Especially since they have other solutions that already work.

  • #2
    A few things to consider:

    1. Building a wall hanger - if your route goes along one of the walls (i.e. the south or west walls), then set up a wall hanger that drops after the robot starts and holds the attachment to the wall. This is generally the most reliable.

    2. Building a release mechanism - in some cases, you can attach the attachment to the robot, but still have it passively release when it hits something on the route. That can sometimes allow the robot to hold onto the attachment a bit stronger than just pushing it.

    3. Weight balancing - you can use heavy parts (e.g. wheels / extra casters or even the Lego weight block) to try to rebalance the center of gravity. I would urge caution on this since it tends to be quite hard to get the weight balancing right.

    Comment


    • #3
      Pushing is never going to be reliable. You need to guide the thing you are moving. The guide can be as simple as a stick that fits in a slot.

      Comment


      • #4
        My kids did something like this. Black is the field wall, green is the device, and red is the robot. They keep driving right a bit to smash the device against the wall.

        Comment


        • #5
          Thanks! I'll use these ideas for sure.

          Comment


          • #6
            Ever since the junk penalty ended a couple of seasons ago, my team regularly uses what it calls a sled. Same thing you are talking about. This season, they have two. They always use the wall to ride along. They use gears, wheels, tires or some other rolling part that rolls along the wall. The robot has to push at the center of mass and, they program about a 5% power difference so that the robot is pushing constantly into the wall to keep the sled tight to the wall.
            Last season, the sled was pushed north and solved the water treatment and attachment in the same move in about 3 seconds.
            Here is the link, it is the first run. Sorry for the poor quality.
            https://drive.google.com/file/d/1o5H...ew?usp=sharing

            This season, they are using a much larger sled and solving the space travel and solar panel while lowering the gate on the crater. They then abandon the wall by simply backing up. If you want to power the attachment, dog ear gears work well and are held together by the force of the robot moving forward but, are easy to back away from without pulling the attachment by binding gears.
            20181110_052510.jpg
            Attached Files
            FLL coach Trash Trek on, State 4x, World 2x, state ref, state judge.

            Comment


            • #7
              My team is doing a similar thing, flattening the gate from the west side prior to doing the crater crossing east to west but we have run into negative feedback from refs.

              Comment


              • #8
                I'm with C.A.T.S Robotics a team out of Spokane we are completing the run in the exact same way and we got into a serious argument with the head ref, emailed the state head ref and got this response:

                Hello,
                The update makes flattening the gate with the robot than sending over an agent craft past the flattened gate acceptable.
                Kevin Torrico
                Head Referee
                FIRST LEGO League
                FIRST Washington

                Comment


                • #9
                  Originally posted by Cats Robotics View Post
                  I'm with C.A.T.S Robotics a team out of Spokane we are completing the run in the exact same way and we got into a serious argument with the head ref, emailed the state head ref and got this response:

                  Hello,
                  The update makes flattening the gate with the robot than sending over an agent craft past the flattened gate acceptable.
                  Kevin Torrico
                  Head Referee
                  FIRST LEGO League
                  FIRST Washington
                  Kevin is right about one thing; the only requirement for the gate is that it is flattened when crossed by the crossing equipment. He's wrong about this having anything to do with the Nov 5 game update. There's never been a requirement that the gate is flattened by the crossing equipment, or that the equipment that flattens the gate has to cross between the towers or travel from east to west.

                  Comment


                  • #10
                    Originally posted by Dean Hystad View Post

                    Kevin is right about one thing; the only requirement for the gate is that it is flattened when crossed by the crossing equipment. He's wrong about this having anything to do with the Nov 5 game update. There's never been a requirement that the gate is flattened by the crossing equipment, or that the equipment that flattens the gate has to cross between the towers or travel from east to west.
                    I agree -- there has never been a requirement for the gate to be flattened by the crossing equipment or from an east-to-west direction. However, U08 changes when the gate needs to be flattened.
                    Kansas City Region Head Ref 2014-present
                    KC Region coaches and teams can ask FLL robot game rules questions at kcfllref@gmail.com

                    Comment


                    • #11
                      Originally posted by Dean Hystad View Post
                      There's never been a requirement that the gate is flattened by the crossing equipment, or that the equipment that flattens the gate has to cross between the towers or travel from east to west.
                      I disagree.

                      That requirement was eliminated. IMHO up until Nov 13, any equipment that flattened the gate was apparently, by definition, "the crossing equipment". Therefore, all equipment that would flatten the gate would have been required to cross between the towers.

                      The Nov 13 update changed, "the crossing equipment must cross completely" to, "the crossing equipment is whatever crosses completely".

                      The update replaced the requirement with a definition. Under the update, it is now physically impossible for "crossing equipment" to not cross completely. It's like a law of physics. You can't break it even if you wanted to. If it didn't cross completely then by definition, it is not, "crossing equipment". Therefore, there's no longer a requirement for crossing equipment to cross completely. It's simply a definition.

                      Comment


                      • #12
                        any equipment that flattened the gate was apparently, by definition, "the crossing equipment".
                        That was not my understanding from reading the original mission text.
                        FIRST LEGO League Mentor and Referee/Head Referee since 2011.

                        Comment


                        • #13
                          Originally posted by Tom Mosher View Post
                          That was not my understanding from reading the original mission text.
                          Hence the need for the update. But again, in my opinion, that's was the only logical interpretation of the original mission text.

                          Comment


                          • #14
                            I know it is a trap, a circular trap at times. But don't logically interpret the mission text. Just read it. Yes, there are absolutely times when some level of interpretation must sneak in, or just does by our natural selves. Is it reasonable that the mission creators wanted something to drive right over the craters and be in contact with them (simulating a planetary rover)...sure. And is it reasonable that the mission creators put a gate there as some sort of nice finish line for refs to look at and determine if such a crossing had taken place...sure.

                            But that aint what they wrote. Certainly not in the Technically Speaking scoring text. There was never any mention on the act of how/when the gate should be flattened. This implicit or lack of detail was made explicit in U8. Although U8 takes it further (surprising many) and removes even the sequence requirement that gate must be flattened before/as the moment of crossing.

                            Comment

                            Working...
                            X