[quinxorin]

Originally Posted by ksafin

The problem a lot of teams had was the approach.

Many teams used the approach of ramming the bridge with an angle to bring it down.
Although this works fine with a lightweight easily-turnable bridge that most of us built, it won't work with the real bridge.

The reason being, of the torque you had when you rammed the bridge, only a fraction of it is actually used because you're not applying a direct vertical linear push.

We use the wedge approach, but we made sure it worked right by making sure we built our bridge right. It takes 17.1lbs of force to push an official bridge down at the ends, and on one end of our practice bridge it takes exactly that amount of force. (On the other, it takes a little more, just so we could make sure our wedge performed better than it had to). The wedge begins at 37deg above horizontal at the uppermost end, but is slightly concave, so it ends at 39.75deg above horizontal. It extends 13 7/8 from the frame of the robot, is 12 1/2 inches off the ground, and when the bridge is pushed down it clears the bumpers by about half a millimeter. Very close tolerances! It has some slippery plastic (delrin) covering the sliding surface, so there is very little friction. The wedge is pneumatically driven with two 1 1/16, 10" stroke cylinders.

Want to see it work?