Can stuff of the robot, like hooks on a conveyor, enter the Game-Piece (balls) Perimeter?
I don’t know of any rules about that. The only rule is that it cannot damage the balls. Make sure your hooks are soft and flexible, and will not tear the fabric or break the straps.
There isn’t a specific rule about penetrating the Orbit Balls… but FIRST is very serious about protecting the game pieces. If FIRST thinks you are breaking orbit balls too much, they will make you change it.
Especially since it sounds like FIRST might not have an endless supply of these to wreck.
The balls are very easy to break, as if you have not seen or heard. Test it to assure that it will not damage the ball and you should be fine.