2012:Shooter and Collector

Shooter Design

• Turret-mounted
  • Approx. 280 degrees of rotation minimum need final range
  • 1-degree precision
  • Mechanical hardstops
  • Absolute angular position sensor
    • Combination sensors - one on motor output shaft, one on turrent drive sprocket
  • Kit Window motor
  • Geared down 48:188
  • Controlled by speed controller (needed for fine adjustment)

• 2-Wheel shooter
  • Must be able to impart backspin
  • Fixed angle of shot -- approximately 70 degrees above floor
  • Each wheel independently controlled (to control backspin)
  • Powered by Fisher-Price (968-9013) motor on speed controllers
  • Transmission -- AM-0002
  • Sensor for RPM on each
    • Provide sufficient resolution for rapid speed control update
    • Identify sensor characteristics
    • If max ball velocity is 12m/s and if shooter wheel diameter is 6", then approx max rpm is 1500.

• Camera mounted on turret
  • Must have direct light source inline with lens
  • Must be able to tilt; does not need to be able to pan
  • Higher is better to see over robots in front of us

Beater Bar Design

• Fixed position within frame, as close to perimeter as possible
• 1 speed forward, 1 speed reverse
• Driven from a relay
• Pushes balls in and on to first conveyor section
• Banebots RS-775 motor
• Banebots P60 4-to-1 transmission, geared down 2-to-1 for total of 8-to-1

Wings/V-collector Design

• V-shaped collector outside of robot
• Articulated up/in and down/out -- 2-position motion
• Just a plain bars, no actual motion on the bars themselves
• Motion must be able to pull unloaded bridge down from horizontal
• Must extert 10lbs force at the tip to pull the unloaded bridge
• AM-0914 motor and associated gearbox
  • Geared down 2-to-1 for additional torque (2-to-1 gives stall torque of 6200 oz-lbs = 380 inch-lbs)
  • 2-to-1 gearing gives unloaded single-actuation of about 0.433 sec unloaded
  • Loaded (bridge) actuation is about 0.525 seconds
• Mechanical hard-stops
• Absolute positional sensor
• Limit switches on both ends

Ball Movement/Storage System Design

• 3-stage conveyor system
• First 2 stages straight at approx. 45 degree rise
• Intake end begins behind front wheel, about 1" from floor
• Each stage uses....
  • 1 Banebots RS-775 motors [1]
  • Coupled to Banebots P60 16-to-1 transmissions [2]
  • Controlled by Speed Controllers (could have been SPIKEs, but would be nice to be able to slow them for diagnostics)
  • Banner-style sensor at the very inside-edge to indicate that "this ball has advanced fully in this stage"
• Additional banner-style very close to intake end (just past beater bar contact point) to count balls and know when we can stop intake on beater bar

Resources

• Ball Trajectory Calculation spreadsheet
• Math behind the above spreadsheet
• Foil Sim III - Air flow simulator; useful for approximating drag effects on a ball
• Motor Specs from FIRST

Shooter and Collector's Engineering Notebook

Week 1

• 1/14

Week 2

• 1/15
• 1/17
• 1/18
• 1/19
• 1/21

Week 3

• 1/22
• 1/24
• 1/25
• 1/26
• 1/28

Week 4

• 1/29
• 1/31
• 2/01
• 2/02
• 2/04

Week 5

• 2/05
• 2/07
• 2/08
• 2/09
• 2/10
• 2/11

Week 6

• 2/12
• 2/13
• 2/14
• 2/15
• 2/16
• 2/17
• 2/18
• 2/19
• 2/20
• 2/21

Engineering Notebook Templates Available at:Engineering_Notebook_Template

Please Label All Notebook Pages 2012:Shooter and Collector XX.XX to avoid confusion.