DEWBOT VIII Bridge Manipulation

1640's Bridge manipulation requirements for Rebound Rumble are:

• Wide chassis orientation to facilitate triple balancing
• Center of mass low enough to prevent robot tipping on inclined and dynamic bridge with robot in the wide orientation
• Pivot "brake" to prevent movement on bridge after achieving balance
• Ability to quickly and certainly lower the bridge to enable mounting from a robot wide side
• The original bridge manipulation mechanism was integrated into the top loading ball hopper

Additional nice to haves were identified after gaining some competition experience:

• Bridge arm can be used to influence center of mass and therefore balance
• There is value in being able to push the bridge up as well as down
• A hook could be employed to link robots to enable hanging off the bridge edge in triple balancing

DEWBOT VIII's bridge manipulation approach & mechanisms witnessed the greatest changes of any functional area during the competition season. Also the greatest improvement.

From a game-play standpoint, the Bridge is HUGE. Both in qualifications (where the coopertition bridge is critical for Qualification Score) and in eliminations (where triple balancing makes an alliance tough to beat), being able to control the bridge and balancing is a critical aspect for success in Rebound Rumble. We ended up being a pretty competent bridge robot (but not best in class).

Key Technical Challenges

• Our 4-wheel drive-train does not allow us to hang off the edge of the bridge safely
• Our shooter is high; a lower center-of-mass would have been beneficial for balancing (especially triple balancing)
• High center-of-mass, wide orientation and 4-wheel drive-train means that we cannot be the last robot on the bridge in a triple balance (we flip over backwards)
• A stinger would therefore make no sense for us
• The decisions for pivot drive and barrier crossing lead to a decision to forgo pneumatics to manage robot mass - pneumatics would have been very useful for bridge manipulation
• The decision to cross the barrier with pivot drive also committed a lot of brain time to the drive train and chassis design

Concepts (Gen 1 - Build Season)

• Bridge manipulation would be accomplished by an angled protrusion (Bridge Arm) on the robot front - when the robot ran into the bridge, the Bridge Arm would push the bridge down, allowing the robot to mount the bridge
• Force to push the bridge down would be provided by the robot's motion
• The Bridge Arm would be articulated with two positions - no protrusion when raised - able to push the bridge down when lowered
• Limit switches to control the two positions
• The Bridge Arm would support a lycra hopper for top loading - when bridge arm is deployed, the hopper is open for Outbounder feed

Gen 2 ( Lenape)

Gen 3 ( IRI)

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