Fork type End Defectors & Ball acquisition

[dtengineering]

Originally Posted by M. Krass

We had some trouble with the balls rolling off to the sides. We fixed that by adding "mantis claws" -- two protrusions over the top of the ball. When we tip our forks back, the protrusions compress the ball a bit and keep it firmly in place. It works great.

Yeah... it does work great. We got to watch those mantis claws in action just a few more times in the quarters than we really wanted to.

Our grippers aren't exactly fork-type (www.youtube.com/dtengineering) but we also found it to be a big problem when we went too far underneath the ball, like we did in Portland.

We swapped the hockey sticks to curve out, not in, and then put a spacer on the gripper pneumatic so it couldn't close all the way in. We also changed the code to give a quarter second delay between closing the sticks and lifting the sticks. This made a huge difference in our ball grasping ability and we were even able to pick it up "on the roll" once or twice in Seattle.