Forwards and Backwards Ball Pickup

[bEdhEd]

My team has a design for a "Y" shaped ball holder, launcher, and catcher, like "Draconis." We thought it would be a good idea to have a robot that could pick up from the front and back, so relaying balls between alliance members is easy, making turning less necessary for assists.

It is well known that an effective rolling ball pickup that has two rollers needs to have the top roller in front of the bottom roller in order to pick up this year's game ball with few or no problems.

Now, here's the issue with this: If you have a mechanism that has the top roller always out further than the bottom, flipping it over to pick up from the back will cause the bottom roller to stick out past the top roller, because of the switch between what is considered the "top" and "bottom" roller in your frame of reference, and can make the pick up less effective.

We solved this by having a structure attached to the "Y" that holds another piece of structure that slides inside it, so the length of both arms of the "Y" are variable. We have a design that allows the robot to have the top roller always stick out in front of the bottom, regardless of the "Y" mechanism picking up from the front or back. We did this by having the sliding structure attached to a specially shaped track that allows its length to change as the structure pivots, without using extra power, like motors and pneumatics, or anything complicated like gears or linkages. In fact, there are few moving parts, and it is strictly mechanical, but I won't let anyone know what it looks like just yet. I'll post about it later in the season.

Have any other teams considered doing front and back pick up, and have been successful? If so, I would like to know, and have you done something else other than a "Y" shaped mechanism to attempt a front/back pickup? I'm just asking if other people have tried or considered this, since I didn't find a thread about this, and i'm not asking for anyone to share their designs, but if you wish, feel free to do so.