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    I spent the afternoon working in the mechanism to couple the rotation of the arm with the raising and lower of the "fruit" cover. I was surprised by size of the counterweight required to pull the cover back up once the arm has been pulled down (and this is all on dry land). I hoped to create a large delay between when the arm is pulled down and the cover moves back into place. After some (enjoyable) attempts an engineering a solution, I came to the conclusion that it would really require some electronics to do everything properly. That's not going to happen...

    So, here's Plan B:
    • The cover will always be in the open position (at the bottom of the top panel).
    • Teams may attempt to shot torpedoes through any of the openings, however, it will only count as the open target (800 pts).
    • In order to attempt the "covered" areas for the proper points (1000, 1500), the vehicle must pull the arm down
      • The arm must be moved from it's starting position (~30°) to past horizontal (~90°)
    • Once the arm is pulled down, the vehicle may attempt the Covered Large and Covered Small openings for their respective points.
      • We can create an artificial countdown timer (15s?) once the vehicle moves away from the arm. If the time expires before a shot is taken, the points revert back to the open target.

    I believe this is the best way to keep the intention of the task.


  • #2
    The "dummy" lever sounds fine to us. However, the countdown timer at 15s is quite short! Computer vision with out little CPUs take longer than we want so having a longer countdown would be nice. I would think 1.5-2 minutes is reasonable.

    Alternatively, could we have a slide off cover like in past years?


    • #3
      We would prefer it if you could stick to the original method of requiring to pull down the arm to open up the hole instead of leaving the holes open. Rather than having a resetting mechanism, it can be simpler by just requiring the course to be resetted manually everytime it is attempted. Same point for what we made in the other thread, now we need to change the entire logic and sequence for the task that we have tested for the past two months

      You can see the video of how we did a mock-up of the task(definitely not the most robust set up but it works):
      Last edited by bumblebee; 07-09-2018, 08:40 AM.


      • #4
        What Dave is proposing shouldn't change your logic and task sequence. It is still required to pull down the covering before you can shoot into the holes


        • #5
          ...which is why I put a "?" I'm open to 90 or 120 s (none of my original ideas would have worked for that length of time anyway).
          It's too late to change it to a sliding cover

          Manual is a problem with limited divers. During a run, the diver needs to keep an eye on your vehicle. I don't want your vehicle to strike into something because they were off trying to reset the arm after your vehicle leaves. And if they reset the course while your vehicle is back on the dock, that would cut into your time (practice, semi-finals, etc.). It really wouldn't work for the finals.

          I like you pull mechanism. I was going to ask the same, why does it change your logic and sequence?


          • #6
            Hi Daveman,

            We check whether we have successfully pulled the lever by detecting the open holes. This determines whether we reattempt to pull down the lever or to go for the shot. This kind of logic sequence, where the robot determines its next move according to different scenarios, is a huge part of autonomy. If the holes are left open, it would be hard to determine whether the lever has been pulled.

            Regarding the resetting of the course, didn't the divers have to do similar things in past Robosubs such as resetting the bin covers, pipes etc. And even with your proposed changes, there is still a need to reset the lever. So we don't see why this will be a huge issue.


            • #7
              I was thinking the same thing. True, there have been tasks in the past that the diver had to reset. I'm trying to get away from that, and maybe I eventually will.
              I agree it is a huge part of autonomy.

              My intention for Plan B was to keep the idea behind the task the same. Every time a vehicle attempts the task it must pull the handle first.

              Plan C: Pulling the arm once causes it to stick open
              Would mean that until the diver has the chance to reset the task, the cover would be off the openings. So if/when a vehicle revisits the task, there is a possibility the cover would be down and would not have to pull the level a second time.

              So bumblebee , with Plan C, if you don't pull the lever down far enough the first time, it would be stuck somewhere mid-pull. It would not be back up the top where you would expect it. So would you be able to pull it a second time?

              Also, do you pull the lever first and then check the opening, or check the openings and then pull the lever? I suspect you pull the lever first, and I also suspect that you do everything in your power to make sure you pull the lever far enough so that you don't have to check the openings and the pull the lever a second (or more ) times. (At least, that's what I would do).

              Beside the reset issue, I'm trying to make this as smooth as possible for you to complete.


              • #8
                Hi Daveman ,

                With plan C, in the scenario that the lever is stuck somewhere mid-pull, we would be able to detect that the hole is not fully opened then proceed to pull it a second time. And yes, we pull the lever first then check for the opening before the robot decides what to do next. It is also very unlikely that we will revisit the slots in a single run.

                Really appreciate all the help Dave!


                • #9
                  Soooooooo, aside from having to not go back a second time to pull the arm further, it doesn't really change your logic or sequence.

                  At this point, I'm good with either Plan (B or C).

                  Plan C, ultimately is better, so let's go with that one, unless someone really objects. I need to see how far the arm needs to be pulled in order for the upper holes to be open, but that probably won't happen until the weekend.

                  Plan C:
                  • The cover is in place at the top covering the upper holes
                  • The arm is pulled downward which moves the cover downward and opens the holes
                  • Due to, lots of things, the cover is held down until reset by a diver
                  • While the cover is down, maximum points are awarded with those associated openings.