Sometimes Bumpers & Kickers don't mix

[=Martin=Taylor=]

Originally Posted by NOV8R

Yesterday when we put bumpers in the correct position on our kicker prototype and kicked , we found out the ball hit the bumper and deflected noticeably. When we did the math we found out why. Our ball is 3 inches deep in the robot when kicked. That makes the top of the ball another 1 1/2 inches outside the perimeter. The bumper is a 2 1/2 pool noodle on a 3/4 piece of plywood. The bottom of the bumper could be as low as 10 inches above the ground or only one inch above the top of the ball. Doing the math a triangle with a base of 1 3/4 (3 1/4 - 1 1/2) with the other side of 1 inch has an angle of 30 deg. That means a ball leaving the robot at an angle of more than 30 deg is going to hit. If the top of the bumper is 16 inches above the ground then the triangle other side is 2 inches. That makes the angle a little over 45 deg. That means if you kicker is designed for max range (ie 45 deg) it's probably going to hit also. Bottom line is you really ought to try out your kicker with bumpers in place before you finalize your design. We're redesigning our kicking shoe for a flatter kick. I'm glad we found this out now rather that we tried to kick the first time we had the robot completely together

The bumpers are 5" tall, and the bumper range is 10-16" above the floor. So couldn't you move them up a little and get 2.25" of clearance above the ball?

The bumpers are also rounded, so the ball can go "through" them a little.

And unless you're getting really far under the ball with your kicker, its pretty hard to get 45* anyhow...