So for this year the Perimeter of the frame can not exceed 120" so does this include the wheels as for our design we are planning on having the wheels outside of the metal frame so we are more sturdy yet our frame as in just metal is 116" for the perimeter so does anyone know if this will be allowed or not. for bumpers we are planning on having some upside down L pieces extruding from the frame that we measured at 116". so does this mean it must be smaller?
Yes it includes the wheels. If the pieces of L are sticking towards the outside and those are your farthest point out that is your perimeter. If your wheel/tires are the furthest point out that is your perimeter.
You need to rethink your design. The FRAME PERIMETER is not defined by what you might usually think of as your ROBOT’s frame. The FRAME PERIMETER is the outermost points on your ROBOT within the BUMPER ZONE (this year, 4-12 inches from the floor). Now in reality that means the outermost points of your ROBOT period, because you can’t have anything stretching outside the FRAME PERIMETER when you start the match.
So that means several bad items off news for your design. First, if the wheels are outside your “frame”, the structure of your ROBOT, the wheels now define the FRAME PERIMETER. So maybe you’re too big. You also have to have a way to attach BUMPERS to the FRAME PERIMETER - hard to do if the FRAME PERIMETER is defined by your wheels.
The good news is that we’re only halfway through the build season, so you have time to refactor.
They talk about rapping a string around the robot at its widest point(s) and then measuring the length of the string as <120". This method is used to allow concave shapes. A simpler way to think about it might be: what size shipping box would I need to put the robot in and then what is the perimeter of the box. I assume you want your wheels included in the shipping box.
BTW: in the old days before switching to “perimeter”, they actually had an inspection box you rolled your robot into and you had to be able to closed the door.
To clarify the part of your post I highlighted: Yes, wrapping a string (tightly) around the ROBOT defines the FRAME PERIMETER. It does allow concave shapes. But the key point is that the FRAME PERIMETER does not follow the concavity; rather it skips over the concave part following the string. The points where the string touches the ROBOT structure again are not corners and they don’t specifically require BUMPERS. But if there is a corner less than 8 inches from the point where the string touches the structure, you would not be able to properly install a BUMPER protecting that corner, and it wouldn’t be legal.