Control of a Pneumatic Cannon

1
Control of a Pneumatic Cannon

• Team 4
• Alex Lai Kyle Koepf
• Chris Ballard Blake Gower
• Tim Tran Adam Sneller
• Danny Tran Bryan Grinnell

2
T-Shirt Cannon Overview

• Mechanical
• Air tank
• Solenoid Valves
• Firing Pressure
• Electrical
• Mircocontroller
• Relay
• Transistor
• Voltage Regulator

3
Overall Mechanism

• Two pressurized air tank
• Primary air reservoir at high pressure
• Intermediate tank
• Pressure stepped down for firing T-shirts
• Solenoid Valve
• Allow air from primary tank into intermediate
  tank
• Firing
• Pressurized air supplies an impulse to the
  T-shirt
• T-shirt is propelled outward from barrel

4
Impulse-Momentum

• Impulse
• Integral of applied force with respect to time
• Causes a change in momentum
• Requires detailed knowledge of F(t)
• Often unavailable or difficult to obtain

5
Impulse-Momentum Equation

• Two Requirements
• Calculation of average force,
• Knowledge of duration of application,

6
Projectile Motion
Initial conditions
Solve
7
Projectile Motion

• Launch Angle
• Create variable angle cannon
• Minimum 10 when tank is driving
• Maximum 60 for shooting
• Utilize linear actuator to facilitate motion
• Initial Launch Velocity
• T-shirt must reach upper-deck of Breslin Center
• 25 m/s was found to allow this
• How will this launch velocity be obtained?
• Must find a suitable air pressure and volume for
  the intermediate tank

8
Air Pressure System
Starting from rest
Average Force can be expressed as
Average Pressure can be expressed as
For the valve opening time from Impulse-Momentum
9
Air Pressure System
Using the Ideal Gas Law
Solving in terms of V0

• Do not account for
• Friction
• Acceleration
• Air leakage
• Non-linear changes in
• Pressure
• Volume

Do these values make sense?
10
Air Pressure System

• Selection of Primary Air Tank
• Must fire as many shots as possible
• Largest available tank 110 in3
• Maximum pressure 4500 psi
• Selection of pipe for charge tank
• Must not burst under regulated pressure
• 2 in diameter
• Selection of PVC pipe for cannon
• Must be able to fit shirt
• Diameter D 3 in
• Length L 26 in
• Time for T-shirt to exit cannon

11
Air Pressure System

• Selection of Linear Actuator
• Stoke Length
• Force Required

Cannon
17.5
CG
Force required
6.5
Pivot
12
Air Pressure System

B
13
Electrical Components

• Microcontroller (PIC18F4520)
• Programming
• Relays (EC2-5NJ)
• Electromechanical switch
• Transistors (2N2222A)
• Electronic switches
• Amplifiers
• Voltage Regulator (LM7805C)

14
Voltage Regulator

• LM7805C voltage regulator to power the PIC
• The input volt will be 12V from the battery
• Output 5V

15
Relay Configuration

• PIC pins
• 3 Relays
• 2 for Solenoids
• Warning Lights
• Relay Pin
• Pin 1 to PIC
• Pin 9 to 12V
• Pin 8 to solenoid valve
• Pin 12 to 5V

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Relay with Transistor

• Directly connect from PIC to relay
• High voltage to trigger relay
• Multiply relay with PIC
• When it is high (ON), completes the transistor
  circuit, which causes a 5V drop across the relay
• It triggers a switch from pin 9 (12V) to pin 8
  (solenoid value)

17
Relay Diagram
18
Launcher Programming

• Software
• Receive Signal
• Sampling
• Triggering
• Launch Sequence
• Safety Features
• Warning Lights
• Fire button switch accidentally left on
• Wont fire again until switch resets

19
Software Flow Diagram
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Final Product

• Load T-Shirt in barrel
• From the remote, when it switches on
• PIC will trigger the warning lights to turn on
• Open primary solenoid valve to charge the chamber
  to 300 psi
• Second solenoid valve is released which fires the
  T-Shirt

21
Video of T-Shirt Launcher