320 likes | 483 Views
ECE 477 Design Review Team 6 Spring 2011. Left to right: Kirk Iler , Brian Bentz , Stephen Wolf, Fuhe Xu. Outline. Project overview Project-specific success criteria Block diagram Component selection rationale Packaging design Schematic and theory of operation PCB layout
E N D
ECE 477 Design Review Team 6 Spring 2011 Left to right: Kirk Iler, Brian Bentz, Stephen Wolf, FuheXu
Outline • Project overview • Project-specific success criteria • Block diagram • Component selection rationale • Packaging design • Schematic and theory of operation • PCB layout • Software design/development status • Project completion timeline • Questions / discussion
Project Overview • Defender is a basic defense system designed to identify and neutralize hostile targets. It combines a number of modules to create a turret-mounted defense system. • Modules: • Coilgun • Motor system • Image processing • Ethernet connectivity
Project-Specific Success Criteria 1. An ability to fire a projectile using magnetic force 2. An ability to aim the projectile by controlling of the azimuth and elevation angles of the barrel 3. An ability to charge a capacitor bank to a variable voltage, up to 400V 4. An ability to gather images and perform target recognition and tracking 5. An ability for a user to enter commands and display the status of the turret through an external interface
Component Selection Rationale • Camera • Canon VC-C50i with PTZ • Atom Board • Capacitors • 3900μF • 400V max electrolytics(x4). U32L
Microcontroller • PIC24FJ64GB002 • 16bit • 64KB flash/8k RAM • 16MIPS • 3.3V • 44 TQFP • 5 Timers • 1 USB OTG • 2 I2C • 15 remappable pins
Firing Controls - IGBT • Criteria: • Voltage • Amperage • Heat dissipation, Failure mode • Price • Part chosen: • APT200GN60JDQ4 • 600V, 283/600A • 640W, .25°C/W • $42.60 • No sink
Motor42BYG023-R • Step angle: 1.8°±5% • Rated voltage: 12V • Current per phase: 0.4A • Holding torque: 2kg/cm • Mass: 0.2kg
Stepper Motor Controllers DRV8821 from Texas Instruments Controls 2 stepper motors up to 1.5A each 8-40V stepper motors Microstepping modes Edge triggered digital stepping via PWM from Micro
Packaging Constraints Portability – Defender should be easily moved and installed. Weight – lightweight to allow for small motors EMI resistant – To protect circuitry from strong fields present in coil gun. Firing range – Target over a broad area. Keypad – Interface must be easily accessible.
Packaging Layout Four major physical components: Base: Divided metal box containing control circuitry, high voltage capacitors, and power supply. Rotator: Uses stepper motors to aim the Coil Gun; Mounted on top of Base. Coil Gun: Mounted on top of Rotator. Camera: Mounted on top of Base.
Subsections: High voltage Control microcontroller Capacitor bank Atom processor Motors Schematic/Theory of Operation
3.3 V low drop out linear regulator Provides power to the control microcontroller Supplied by rectifier from high voltage system Switching 12 V power supply (4 Amps) Supplies power to the Atom and the motors Supplied by second transformer on Power PCB Power Supplies
Controls 2 direct drive stepper motors with two coils each 10 heat sink grounds to copper heat sink Dedicated I2C port expander Commands include reset, direction, decay mode, step mode 1/8th microsteps Sense resistors and voltage reference limit current to 400 mA Motor Microcontroller
Receives commands from Atom Communicates information to and from circuitry I2C communication bus (400 kHz) USB connection to atom Bypass capacitors Reset circuit Control Microcontroller
The photogates will function by creating a logic high when an object passes through. These will be directly interfaced to general purpose I/O pins. Sends an interrupt directly to the microcontroller to signal available information Microcontroller collects information over I2C Keypad Encoder Other Components
Atom processor • Performs image processing and system command • Communicates with control microcontroller over USB • Communicates with user interface over Ethernet.
High Voltage Power • Changed to TRIAC circuit to switch power. • Measure DC voltage using ADC.
Rectifiers and I2C • 12V transformer and bridge rectifier connects to Communication Control PCB. • 3.3V bridge rectifier.
ADC, LED switch, Coil Protection Diodes • Capacitor bleed circuit connects to capacitor bank. • ADC measures current through a voltage divider. • Protection diodes anti-parallel to coil.
Software Design/Development Status • Computer • Single Executable: • GUI - implemented • Java.swing components • Ethernet - testing • Wrapped in to GUI components • Jnetpcap library
Software Design/Development Status • Microcontroller • USB interface- not yet begun • Communicates with atom board • I2C bus to interface to: • Motor microcontroller • Charging controls
Software Design/Development Status • Atom Board • Single Executable: • Ethernet libraries- testing • Winpcap library • USB libraries- not yet begun • PIC family libraries
Camera status • Microsoft Visual Studio 2008 configured • OpenCV image recognition libraries and camera motor libraries installed • Drivers installed for S-Video frame grabber and motor USB to serial cables • Image capture functioning on computer intended for compiling • Minor configurations still needed on Atom, which will be running the executables
Project Completion Timeline • 3/11 PCB submission • 3/21 Atom board Ethernet communication Image processing recognizing stationary targets Start populating PCBs and testing • 3/28 Start programming microcontroller Begin physical packaging • 4/10 Completed packaging and testing • 4/11 Start system integration • 4/18 Documentation and paperwork • 4/27 PSSC Demos