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2018 RoboSub Rules & Tasks

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  • #76
    cuauv

    If you go back to the preliminary Mission posted, these were originally all on the surface. I wasn't a fan, and ask for feedback, and didn't get much (about that part of the task). I pushed two of the funnels 2ft below the surface. You had these dimensions for 3 months.

    All that being said, I'm not against pushing them down to 4ft, as long as no one else is (whether you wish to post here, or send me a message).



    You are probably only slightly more frustrated than I am about the the Chip dispenser. However, you do know the size of the push plate and where the ball will be positioned once it's released. The chip dispenser will be in the competition, you can decide if you want to try it or not. Don't sell yourself short, I've seen a lot of amazing things happen in a couple of days.
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    • #77
      HEU-AUV
      When there is a golf ball in the hole, it will be one color. When you remove (or knock off) the golf ball, it will be another color. Which _should_ help.
      Last edited by Daveman; 07-13-2018, 12:07 PM. Reason: Correct a word (What => Which)

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      • #78
        Daveman

        We have been testing with the Cash In bins taped onto weighted blocks to give them support at all sides so even if we hit the edge of the bin, it doesn't tilt the bin. This seems to be quite nice and stable. Could you do something similarly stable?

        Because no one has expressed concern over moving the sub surface funnels down to 4ft since you suggested it, can we get a decision on that?

        Finally, if we may, can we suggest one more very very small change to the Cash In mission? Could we move the golf balls holes in the bins 0.5" (maybe 0.75") radially inwards? This gets them further away from the edge, is nice.

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        • #79
          We're good with cuauv on the moving close by 0.5" radially inwards away from the edge. We still need to test that following week when we're shipped to the States which is a bum, but we're willing to take the risks.

          On the shifting down to 4ft, we stand by our decision previously, to leave it at 2ft, for the same reasons we mentioned and Dave mentioned above.
          Last edited by bumblebee; 07-13-2018, 08:18 AM.

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          • #80
            We have noticed that the VideoRay thrusters emit a noise around 40 kHz when running. Is it possible to have the pingers emit at something other than 40 kHz?

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            • #81
              Cash In:
              The sub-surface funnels will stay at 2ft (610mm) below the surface.

              The holes to hold the golf balls will be moved inward 0.5". Now they are 2" (51mm) from the center (see attachment)


              cuauv
              And the bins taped to the blocks are still 1ft off the ground? Would it be possible to post a picture? I'm going to work on a design today, and I can post tonight.


              aparikh

              That's true, the VideoRay thrusters do make a 40 kHz noise. The pingers are currently spaced a even 5 kHz apart, and I can't push the 40 kHz upward (since that's the top of the frequency range), which would be the best solution. I can lower the frequency, but that puts it close to both the 35 kHz pinger and the 40 kHz from the thrusters, and I'm not sure what everyone's band-pass is (or whatever they are doing to detect the pingers.

              I'm assuming that you are using Video Ray. One thing you can do is turn off your thrusters when you are trying to listen (doesn't help if there is someone else in the water with Video Ray).


              I'm open to suggestions from the audience
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              • #82
                Thanks everyone for considering and discussing the Cash In funnels. We really appreciate the discussion and don't want to make it harder for everyone.

                Daveman

                Unfortunately our "bricks" were just a quick fix for making the bin more stable. Potentially a more practical way of making it more stable is making a PVC cross section under the bin and having that attached to 4 legs on the outside, as opposed to the one. This essentially makes the bins a table which is harder to fall over when pushed the wrong way.

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                • #83
                  Likewise, I always appreciate healthy dialog!



                  cuauv
                  No worries...

                  Maybe something like.....(wait for it...) this...?


                  With cinder block caps on both ends to hold it to the floor and four zip ties to hold the bin down and in place.
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                  • #84
                    Daveman

                    Is there a reason one side is longer than the other?
                    Because this is just a question of how to best secure down the bins, can you give us a day to test it in water and get back to you? The stand shouldn't affect any other team's logic (hopefully). Looking at the design, we are just worried about the possible rotation if we hit it on the top or bottom side in your picture. Additionally, we have found with our bin that if we don't tape down the center, it likes "doming" a little.

                    Additionally, we had a question about the scoring with Cash In. So there are points for "Drop an object" - does this mean anywhere? So if we pick up the balls from the bins and then drop them anywhere, we get these points? Because there is an additional row for the points for the balls being in the funnels.

                    Also, I would like to bring attention to how we just discovered how golf balls vary widely. This could be some reason to why teams are experiencing different things. We typically test with yellow Wilson balls. However, today, we decided to be adventurous and try blue Nitro balls. These blue balls are larger than the Wilson ones and don't stay as put in the bin holes. They are also a different weight. Upon some research, we found that golf balls only have 2 design constraints - being < 45.93g in weight and > 42.67mm in diameter. So.....

                    On the topic of points, the rules on the first page of the forum doesn't say how many for Find Casino
                    Last edited by cuauv; 07-14-2018, 03:04 AM.

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                    • #85
                      cuauv
                      There's usually reason's for why I do what I do... The offset is to make it easier for the divers to get the spacing of the bins from the pinger correctly.

                      Rotation of what...? The bin? The bin will be zipped tied in four locations to the PVC structure. It might slide a little, but it won't rotate. The frame will be held down with 2 concrete capstones (one on each end). I'll double check that it doesn't dome (thanks for the tip).

                      Points for surfacing with an object. Points for retrieving an object. Points for dropping an object (anywhere, and hopefully, I have enough golf balls).

                      Golf balls: Really! Well, that's just annoying!

                      Points: See attachment for the latest point breakdown from the latest version of Mission and Scoring (soon to be released).
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                      • #86
                        Thanks Daveman !

                        We were just worried about the axis of rotation where the stand connects to the bottom but as long as it's PVC cemented properly, should be fine.

                        Do you know what brand of golf balls you will be using?

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                        • #87
                          Ah, understood. The stand will definitely be cemented.

                          I'm using Nitro Blue and Red and either Srixon Yellow or a cohort found yellow balls with "$" on them (not sure of the brand).



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                          • #88
                            The stand seems to work well for us. I can't tell in your pictures if you have a cross bar underneath the bin, but we put one in and it works well (picture below). We also put 4 tee connectors on each of the ends and it helps stabilize it.

                            We are still very concerned about how easily the balls falls out of the holes. The Wilson balls definitely stay in better but the Nitro balls won't even stay in without the vehicle around! Our swimmer resets them and they fall out before the vehicle can even get to the task.

                            Thanks!
                            Attached Files

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                            • #89
                              Daveman

                              We don't seem to suffer a 40 kHz noise from our Videoray surge thrusters. With that being said, lowering the frequency of the 40 kHz pinger may make it difficult for us to differentiate it from the 35 kHz pinger as in our circumstance, differ by only a few frequency bins while performing a FFT on the sampled signal. A last minute change of the pinger frequency may require us to re-tune various parameters. Thus we hope that the pinger frequencies could be kept the same. Thanks!

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                              • #90
                                interesting observation cuauv. We thought they were all the same. Can we get the diameter of the Nitro and Srixon golf balls that you are using Daveman ?

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