DEWBOT VIII Shooter
From DEW Robotics
1640's Shooter requirements for Rebound Rumble are:
- This is a shooter; not a dumper
- Primarily targeting the top basket
- High scoring reliability (>67%) from Key or closer
- Ability to feed balls to alliance scoring field from the outbounder station
- Backspin to drop into basket and provide dead landing upon feeding
- Fast recycle; one shot per second (minimum)
- Automatic rangefinding & aiming
- Maintain low CoM for bridge balancing & preventing bridge tips
The Shooter system comprises:
- A fixed-geometry overshot wheeled shooter
- A tachometer to determine and thereby enable control of shooter wheel speed
- A camera for aiming
- A Drive Mode specifically for aiming the robot
- A narrow-beam sonor to determine range to back-board
Contents
Key Technical Challenges & Statements
- A high shooter elevation (trajectory) will be needed to score in the top basket
- High trajectory shooters shooting from the Key cannot be easily blocked (regardless of shooter height)
Concepts
- Wheeled shooter was the only serious concept examined (well, there was some catapult testing early)
- An overshot wheeled shooter offers the desired backspin
- To manage mass & cost, it was decided early that a decision to use pivot drive (which was subsequently made) would also become a decision to fix the shooter azimuth relative to the chassis. If we use pivot drive, we will aim the robot; we will not use a turret to aim the shooter.
- The camera should be utilized to adjust azimuth (relative to field). Automatic aiming preferred if (and only if) this could be demonstrated to result in higher scoring than Driver-aimed/Camera-assisted shooting.
- A narrow-cone sonar was specified to determine distance to backboard
- The shooter wheels must be speed-controlled
- The sonar or alternately the operator to supply the set-point for the shooter wheel speed
Prototypes
Prototyping was limited and the final shooter closely resembled the prototype.
Testing prototype on DEWBOT VI chassis
Design Details
Power: Fisher Price -9015 motor with BaneBots P60 4:1 reduction gearbox directly driving a pair of 8" kitbot wheels
- 3900 unloaded rpm (max)
Shooting Angle: 55° from horizontal (fixed)
Tachometer: Nippon-Denso E6DF motor with custom circuit
- Motor Gearbox, shooter wheels and tachometer are all on a common ½" 7075 Al shaft