2014:Shooter Subteam

To do

To Be Done

• Finish design for Ball constraint in kicker
• Find where we need mechanical stops
• Raise battery
• Locate kicker stop
• Clearance for electrical
• Area (Bottom Pan for electrical between motors
• Side Restraints

Conflicts

• Kicker path and D.T. stabilizers

Design Analysis

Stress Analysis

• An alumninum rod fixed where the bearings are

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• A steel rod fixed where the bearings are

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Current Design

• shooting takes 1-2 seconds
• a kicker strikes the ball through 2 bars (cradle)
• Linked with intake with a motor in the cradle structure pulling and pushing intake

Equipment Requirements/Size

- Weight

• 45 LBS

- CIM motors

• 4 mini CIM
• 2 regular CIM

- Control

• PWM or CAN, but PWM may be preferred as it may be faster
• cRio CAN is derived from RS-232 with max data speed of 115,200 bps.

Sat Jan 11

• Still working on Fundamentals for design

• Calculating how far the kicker has to move

• Calculating if motor driven is possible for Kicker

• met with collection
• integrate our cradle with the collection
• What type of material should we use
• Better to have a longer kicker than a lighter one

Accomplishments/Results

• Kicker must move about 80 - 90 degrees
• If you go any less than that you need more motors
• How to stop kicker motion

• nylon strap

• blocking plate

End of Day Design

Sun Jan 12

• Continue work on 3D design in inventor
• Determine geometry of Our kicker to the ball and cradle
• Our kicker has to be curved at some point so that we get the max speed into the ball rather than rotation
• We Finished drive trains CAD
• Worked on CAD for shooter

Tues Jan 14

• worked more with intake to get a linkage working
• messed some more with the geometry of the shooter
• Made a physical mock-up of the shooter

-cradle

• kicker

• Worked more on the CAD mock-up

Current Design

Sunday, January 26th

Overall Design:

Electrical Components mostly placed. 

Kicker Restraint System:

Uses a nylon strap (approx. 10,000lb tensile strength) to restrain the kicker. Springs mounted to drivetrain reduce the sudden stopping of the kicker by absorbing force from the strap.

Spring Physics Calculations - 

Desired Energy to achieve 10m/s Ball Velocity: 65 J (N/m)

Note: Joules are the same as (Newtons * meters)

Assumed Distance of Energy Transfer to Ball: 10 cm (0.1 m)

KE = .5 * k * (d^2) : Derived From Hooke's Law using an Integral

65 Nm / (.5 * (.1 m ^2) = k

13000 N/m = k

Conversions:

Newtons = kg /9.8 m/sec^2

13000 N/m / 9.8 m/sec^2 = 1326 kg/m

1 kg = 2.24 lb

1326 kg/m * 2.24 (lb/kg) = 2971 lb/m

39.37 in = 1 meter

2971 lb/m / (39.37 in/meter) = 75 lb /in = k

Worst Case Scenario Shown  - Motors will shut off before mechanical stop point, meaning energy transfer will not be as bad as shown.

Springs Chosen - 4 Compression, 8.60 lb/in Rate, absorbed over 1.25"

8.60 lb/in * (1.25 in./ 1 in) * 4 springs = 43 lb/in overall

Absorbs at least half of the force from the kicker.