<R04> "Wedge” robots are not allowed. Robots must be designed so that interaction with other robots results in pushing rather than tipping or lifting. Neither offensive nor defensive wedges are allowed. All parts of a robot between 0 and 8.5 inches from the ground (the top of the bumper zone – see Rule <R35>) that might push against another robot must be within 10 degrees of vertical. Devices deployed outside the robot's footprint should be designed to avoid wedging. If a mechanism or an appendage (a ball harvester, for example) becomes a wedge that interferes with other robots, penalties, disabling, or disqualification can occur depending on the severity of the infraction.

<R35> The use of bumpers is strongly encouraged. Bumpers can reduce damage to robots when they contact another robot or field elements. If you choose to use the specified bumpers, you will have both a more robust robot and the traction advantage of a heavier robot. Bumper height has been specified so that robots will make contact bumper-to-bumper and so that the balls will be pushed rather than pulled under the robots. Note
that robot wheel/tracks must be properly positioned relative to the bumpers to avoid trouble climbing the ramp. Obviously harvesting balls from the floor or launching balls along the floor must be done through gaps in bumpers or over bumpers. As the bumper mounts are being designed, please think about carrying the robot. The bumpers do not make good handles. Please do not “lawyer” the bumper rule - it is meant to help.
If used, bumpers must satisfy the following constraints:
• Bumpers must be designed as shown in figure 5-1
• Bumpers must be removable so that they can be weighed separately from the robot
• Bumpers must weigh, in total, no more than 15 pounds including any fasteners that attach them to the robot
• Bumpers must not include sections that weigh more than 3 ounces per inch (i.e. no short bumpers with giant heavy fasteners)
• Bumpers must use a stacked pair of 2-1/2 inch “pool noodles” as the bumper material
• Bumpers must use 3/4 inch plywood backing 5 inches tall as the bumper structure to attach the bumper (“pool noodles”) to the robot
• Bumpers must be covered with a tough smooth cloth (1000 denier Cordura Plus® strongly recommended)
• Bumpers may extend outside the horizontal starting dimensions for the robot (as specified in Rule <R05>) by up to a maximum of 3-1/2 inches per side, nothing other than pool noodles and cloth may extend more than 1 inch beyond the robot boundaries
• Bumpers must be positioned on the robot so that they remain between 2-1/2 inches and 8-1/2 inches above the floor