Disk Orientation

I have been observing and commenting (in my head::rtm:: ) on various threads for the past few weeks. One topic I really wanted discussed but I havn’t seen brought up is disk orientation from the ground. My team decided early on that this would be critical to real accuracy and distance not to mention dependability on the field. But I have yet to see an intake that solves this issue between the ground and the shooter.

Am I just looking at the wrong robots? Or have teams decided that Robot in Three Days proved that it didn’t matter?


I think a lot of teams have been showing good shooter results with upside down and right side up disks. i know my team’s intake can pick up both as well. It’s one of those things that was worrisome at the beginning of the season, but not so much anymore. Just like people said in the beginning of the season last year that triple balances would be rare (they still were rare, but definitely more common than predictions in the beginning of the season).

There were a lot of threads in early January about disk orientation. It turns out that in practice, it doesn’t matter much, especially from less than 20 feet or so.

Okay… I was wondering what other teams had come up with. We figured out a way to orient the frisbees without much modification to the other parts of our design. I was looking for some teams with super cool looking 180 degree rotationals built into a conveyor or something :D. Thanks

Team 706 designed a disk orientation mechanism into our robot this year. It is as of yet 100% effective, however we can’t release all of the details yet. Ill be sure to post a link when we are ready.

If I had to guess, teams fall into one of two camps. Either they don’t care about orientation, or they’ve found it to be very important, presumably because they’re shooting a long distance or doing something unique in the way they shoot. The teams in the latter group have put in a lot of clever design work into their flipping/feeding mechanisms - since this is just hard as shooting the disks - and aren’t ready to share them publicly.

I guess we’ll see in a week or two. :slight_smile:

We prototyped a fully mechanical disc orientation mechanism. It allows right side up discs through and flips upside down ones over before passing through. However, we didn’t have space for it n the robot, so we won’t be using it.

We have built an upside-down detector, but it has not been properly tested yet.

Basically, the f-bee encounters a semi-circle mounted to an arm. The f-bee raises the arm, triggering a switch. If the f-bee is upright the switch stays up for a period of time. If upside down it goes up and comes right back down.

We read the pulse width to decide what we have. If upside down we spit it out, and will look for another f-bee. We do not try to correct the orientation.

We give this about a 50% chance of working.

I though this same way early on in the season. Until we built our shooter prototypes. When you shoot out the discs and then land on the floor, 4/5 times they land upright. Frisbees are airfoils and they want to stay upright. So we decided that picking up and shooting upside-down discs isn’t likely or important. Besides, the optimal situation is to never let a disc land on the floor, you want them all to go in the goal. :wink:

Many of the high range shooters will likely rely heavily on the human player station, where disk orientation can be controlled.

I agree. I think that most of the frisbees shot this year will be loaded at the station. We can load four frisbees in two seconds at the loading station. We have a prototype of a frisbee gathering device (thank you 1712 for some helpful design ideas) but even if it ends up working perfectly we think we will still load most of our frisbees at the loading station.

Was that including contacting the wall? I would think that the wall would increase the randomness of the frisbees orientation by more then that.

Also, have you tried it firing against the nets that surround the field. One strategy I see being imployed by feeder station bots is if they are blocked by an 84 in defense bot (which they will be if that strategy becomes a meta-game). They simply change angle and chuck them as hard as they can at an angle designed to get over such a defense bot. Then they need a robot with intakes and at the far end to suck frisbees in and fire them. Which it sounds like doesn’t require orientation at all. So in that case a third robot needs to be brought in to take those frisbees which are landing fairly randomly do to the net having a bit of give. In that case orientation by that bot is key in order to insure range and some accuracy so it could then quickly turn and fire those to its corresponding offense bot on the other end.

Not sure if that made any sense. I am currently suffering from overexposure to coolant fumes :stuck_out_tongue:

Unless the wall matches the curvature of the top surface of the frisbee, then I don’t see them falling upside down after hitting a wall. The only possible case would be if there is no rotation on the frisbee. The net on the other hand might cause some more variances, but unless you were trying to hit the net, you’re not going to hit it.

Most of the videos that teams have posted have shots hitting the wall with serious force at an angle of at 45 degrees or less from the bottom of the frisbee to the wall if they are shooting from the area around/in front of the pyramid. Will that change how they land? Will a long and herefor more flat shot illustrate what your are hypothesizing better?

This just makes me more excited for week 1 and seeing how the game developes with time. The super complicated stratagem I posted earlier was more of a championships level of depth in an alliance. I think you will see 2 of those three positions filled on most alliances that win early regionals. Or not. :slight_smile:

Just adding a tiny bit of info on 706’s flipper to up the curiosity factor. Our fully internal disk flipper is completely passive. No sensors, no coding no electricity, no pneumatics and fully effective at flipping upside down bee’s and leaving right side up bee’s alone.
Pics coming soon.