here is a nice shot of our gripping mechanism. We hold tubes from the inside, so that no robot is able to unhook it.
The wheels at the bottom are our “kicker”, it gives the same effect as stepping on a tube, “kicking” it up into our gripper. We’re able to pick tubes off the ground, while driving.
On the far back, you can see 2 of our dog logos, which are actually the heads of some limit switches. When the tube comes up, it hits the limit switch, throwing the gripper outward. The arms help guide the robot onto the plates.
On the inside of the gripper is a IR range finder, so that when the driver gets close enough to the rack, the robot will automatically throw the tube onto it.
feel free to PM me to get any more detail on it.