Can a claw mechanically grab a riser or is it only permitted with a stationary claw?
Hello @Robotics_in_Room_30! As with most things in robotics, it’s legal if the game manual doesn’t make it illegal. In this case, it is perfectly legal. And there have even plenty of teams who have used a design that require a moving claw (active claw) rather than a stationary claw (passive claw) to work. I would recommend doing some research (on vexforum or youtube) to find some of these designs.
When you say mechanically grab, do you mean something that closes and grips the Riser? If so, then yes, this would be legal. Can you see anything in the rules that made you think that it might not be?
Edit: too slow for @Noah10851B
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To answer this question with the game manual, check out rule G13 which supports what has already been said. I have bolded the applying portion of the rule:
Don’t damage the Field or Risers. Robots may not grasp, grapple, or attach to any Field Elements. Strategies with mechanisms that react against multiple sides of a Field Element in an effort to latch or clamp onto said Field Element are prohibited.
While Robots are permitted to grasp, grapple, or attach to Risers, Robots which cause damage to Risers would be considered in violation of this rule and/or S1.
The intent of this rule is to prevent Robots from unintentionally damaging the Field or Risers. Minor violations of this rule that do not affect the Match will result in a warning. Score affecting offenses will result in a Disqualification. Teams that receive multiple warnings may also receive a Disqualification at the Head Referee’s discretion.
This means that it is 100% legal to “grasp, grapple, or attach to the Risers” so long as you don’t damage them. So you could use a claw that holds onto every surface of a riser and as long as you don’t break it, it would be legal.
As far as specific designs go, I’d highly suggest @Noah10851B’s suggestion: