Re: All About Ball Control
 

here's a pic of the front of our robot showing our ball control mechanism... i don't want to share all of it's secrets... but yes those are rubber bands on the roller. It works pretty well.

http://www.oregonfirst.org/wp/wp-upl...6-DSC_3468.jpg

you can see video of it in action at the Oregon regional here
http://frcstream.com/main.php (click search for events, event name: Autodesk Portland Regional - 2010)

Re: All About Ball Control
 

I don't have any pictures, but I can describe the overall idea pretty well.

There's a Tunnel down the center of the robot that's slightly smaller than the ball. At one end of this tunnel are a series of small fan blades attached to a motor. When the motor is turned on, the fans move such a high volume of air that it creates a suction force that can draw balls in from about a half a foot away.

Re: All About Ball Control
 

Here's a video showing our competition robot with a lot of footage of our ball control mechanism. As you can see the primary components are rwo FP motors coupled to two Banebot 20:1 gearboxes powering two Banebot 3 7/8 wheels. The mechanism also has a way (ram light) of telling the driver when he is in control of a ball. The driver controls the mechanism via a second stick (left) on the control box. That stick also spins the robot left or right to aim. We have a practice robot with the same mechanism installed. The past few days the driver has been practicing ball control by keeping a person from being able to take the ball away from the robot. The mechanism works very well and we're anxious to see it in action on the playing field. Here's the video http://rambotics.com/video5.html

Re: All About Ball Control
 

Avast anti-virus reports a Trojan JS Downloader-LQ [Trj] at your link.

Perhaps this is a false positive, but I thought you should know.


~

Re: All About Ball Control
 

1918 uses a pool noodle on a 3/4" aluminum tube spindle that rotates at about 600 rpm. The noodle slips on the spindle with a few in-lb of torque. The noodle height is adjusted so that the ball contacts the noodle about 3/4 inch before it hits the 3" setback stop. The noodle slips on the spindle when we have a ball. It can pick up a ball with the robot moving at full speed withoug bouncing off. It holds during turns, and we can back up at partial speed. The bore of the noodle wears out, so we need to replace it every dozen matches or so.

Depending your design, many teams can make a very simple, limited ball collector with no moving parts. Install a piece of soft foam rubber at the the top of the 3" ball penetration zone (on the underside of the top of the ball opening), flush with the front of the robot. The bottom of the foam should be set so that the ball compresses the foam by about an inch before it hits the 3" backstop. This won't hold a ball while backing up, and has limitations during turns, but it does a decent job when you are pushing a ball. Basically, it just puts some friction between the robot and the rolling ball that holds it against the robot while driving forward.

Re: All About Ball Control
 

639 doesn't actually use an active ball control mechanism, however our kicker is also quite different from the "average" team's kicker.

First of all, we placed memory foam over the majority of our kicking area, allowing us to herd balls easily without them running away the moment touch them.

Also, our kicker is pneumatic powered, but it is also a spinner, using a clutch against a dual-FP motor gearbox to allow us to slide out the actual kicker without the ramming of the motors. Behind the memory foam, our kicker gets to target speed, then when we are ready to kick the pneumatic pistons fire, releasing the motors so the kicker spins on momentum. Since it is constantly moving, we have a 1-2 second window where the ball can be kicked with a good amount of force after we tell it to actually kick, removing the major need to possess balls

Anyways, we only have .5 pounds to spare. How can we not use it on cool LEDs?

P.S. image of our kicker here, and on the overall robot here