This year we decided to focus on scoring high in autonomous, gather disks from the floor when they are available and the feeder when necessary, then hang for 10 points at the end. One key to a high scoring autonomous mode is gathering from the floor. Here is a video of our prototype floor pickup mechanism. While not perfect (it is, after all, a prototype), this has given us the confidence to proceed with final design and fabrication of a competition quality version.
The arm is mounted on our practice bot chassis. The software team has been working with the competition bot drive train for a week and a half (the second key to a high scoring autonomous mode).
Our first prototype (over the front bumper) exceeded the cylinder by quite a bit. This one fits the cylinder exactly with the arm horizontal (maximum extent of the arm) and is a little within the cylinder when down on the floor.
The width of the scooper matches the width of our frame, for maximum disk gathering. The length of the arm is the maximum allowable by the cylinder.
If you were to change the pickup funnel so it’s not centered, you could hit 2 discs simultaneously and not worry about the first one clearing before the 2nd disc comes in and jams the whole thing. You may also be able to increase the belt speed on that side slightly such that the offset side rollers pull disc #1 in faster, making it clear the intake before the 2nd disc’s apex gets in front of it. It’s pretty easy to increase the belt linear speed by increasing its drive roller slightly.
This was our original idea. If the “funnel” is offset, it has to go over top of the bumpers. Without going into a bunch of the other constraints (non-interference with the shooter, shallow scoop angle), an arm that was long enough to go over the bumpers broke the 54" cylinder when horizontal. With a couple more weeks to tweak, we probably could have made it work. But, this year we are following the motto: Having a good robot early is better than having a perfect robot late.
This is one of the things we may try, if jamming proves to be a problem. There are many tiny tweaks possible to speed up one side, or slow down the other.
This looks awesome! I’ve been working on something very similar, only different . Does your bottom plate scrape the ground? If so, how does this affect driving?
For those of you wondering where the frisbees go after leaving the pickup arm, here’s a photo.
The disks go from the pickup arm to a simple conveyer, which drops them in the top of the hopper. The hopper holds four disks. When full, (or anytime, really) the hopper flips up to the shooter, and the disks are rapid fired by the shooter arm.
How are you moving the disks from the hopper to the shooter? I see a cylinder on the top level that I assume is involved, but can’t quite tell what it’s designed to do.
My guess is that the whole hopper assembly rotates up, a really nice compact way to move frisbees (conveyors take up alot of room). The only negative is it looks like they won’t be able to pickup and shoot at the same time, although I am not sure how required that will be this year.
I gathered that. I was curious how the discs then exited the hopper, but I think I figured it out. The cylinder mounted on top of the wood board seems to be attached to a piece that will rotate and push out the discs.
It looks like the shooter platform can articulate to two angles based on the cylinders of the front of the robot. Can the hopper unload into the shooter at both angles? Or is one configuration simply for starting conditions?
I assume this robot is going to play heavily on the strategy of picking up missed frisbees around the pyramid and scoring them, which was the other major design philosophy that was discussed on 422.
Are we going to be seeing any vision targeting on the robot this year?
. Does your bottom plate scrape the ground? If so, how does this affect driving?
