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Design Review: RoboSiM Robotic Surveillance in Motion Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

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Page 1: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

Design Review: RoboSiMRobotic Surveillance in Motion

Bryan McDonnelMichael MizeRyan TaylorMiles Whittaker

Page 2: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

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

Page 3: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

RoboSiM Overview

Robotic surveillance vehicle

Navigate to a target

Avoid obstacles Survey target

location by recording audio

Page 4: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

Project Specific Success Criteria

Demonstrate an ability to: Display the current status of the robot on

an external display. Read from and write to a portable media

device. Make navigational decisions based on

sensor, GPS, and digital compass data. Control the robot using steering and

motor drive. Capture and encode audio.

Page 5: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

Block Diagram

Page 6: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

Component Selection

Microcontroller: PIC24H Audio encoding▪ G.711 needs 1 MIPS▪ Capable of 40 MIPS▪ Free libraries from

Microchip Numerous peripherals▪ 2 SPIs, 2 I2Cs, 2 UARTs

Robust IDE▪ MPLAB and

development board

Page 7: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

Component Selection

GPS Module: Skytraq VENUS Accurate▪ < 2.5m CEP

Configurable update rate▪ Up to 10 Hz

Form factor▪ Breakout board▪ SMA connector

Page 8: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

Component Selection

Sensors: Ultrasonic Range▪ 6” – 254” with 1”

resolution: (Vcc/256)/in

▪ Wide beam for general obstacle detection

Multiple interface types▪ Digital serial▪ Analog voltage▪ PWM

Page 9: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

Packaging Design

RP5 Chassis Tank treads Small

Motors 6” per second

nominal Forward-mounted

microphone Forward and side-

mounted ultrasonic sensors

Page 10: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

Packaging Design

Top View

Page 11: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

Packaging Design

Page 12: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

Theory of Operation

1. Obtain data from SD card and note current location

2. Validate SD card coordinates and initialize systems

3. Start motors and travel to destination while continuously sampling sensors

Navigate around objects using compass and sensors

4. At destination, sample microphone using ADC

5. Return to starting location

Page 13: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

Theory of Operation/Schematics

Five Key Functional Blocks Object Detection Navigation Motor Control & Power Audio Capture Display and Storage

Page 14: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

Block Diagram

Page 15: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

Microcontroller

Page 16: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

MicrocontrollerReset

PICKIT-2

Page 17: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

Microcontroller

Audio

Page 18: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

Power - Battery

Regulators designed to accept 8 – 11 V input

8.4V NiMH AA rechargeable battery pack used as input 2200 mAh

Buck regulators used to produce 7.2V and 3.3V output

Motors draw 2.45 A each at stall

Page 19: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

Power

Page 20: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

Motor Control

Page 21: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

Navigation

Digital compass and GPS used GPS runs at 10 Hz, Digital compass

at 20 Hz Dead reckoning between GPS samples

GPS sends NMEA* string over UART that will be parsed to determine current location Algorithm described in software

narrative*National Marine Electronics Association 0183 Standard

Page 22: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

Object Detection

Three ultrasonic sensors attached to chassis Front-, left-, and right-facing

Sensors run in continuous scan mode at 20 Hz

Distance to object corresponds to 6.45 mV / in [(Vcc/512)/in]

Sensors sampled by ADC using 12-bit resolution

Page 23: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

Audio

Page 24: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

PCB Layout: Overview

Low-Power

High-Power

Page 25: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

PCB Layout: Power Supply

7.2V Supply

3.3V Supply

Page 26: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

PCB Layout: Power Supply

75mil traces

High Current(up to 5.1A)

Page 27: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

Routed to shorten current loops

(both regulators)

1

3

2 4 5

PCB Layout: Power Supply

Page 28: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

Routed to shorten current loops

(both regulators)

1 32

4 5

PCB Layout: Power Supply

Page 29: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

Redundant caps

to prevent brownout

during motor load

changes

Additional caps

PCB Layout: Power Supply

Page 30: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

H-Bridge Controllers

PCB Layout: Motor Control

Page 31: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

H-Bridge Controllers

75mil traces

High Current(up to 5.1A)

PCB Layout: Motor Control

Page 32: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

Data & Power Traces

Separated

Data

Power

PCB Layout: Motor Control

Page 33: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

Planned ThermalRelief Plane

PCB Layout: Motor Control

Page 34: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

PIC24H Microcontroller

PCB Layout: Microcontroller

Page 35: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

PCB Layout: Microcontroller

four decoupling capsplaced close to pins

Page 36: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

PCB Layout: Microcontroller

Two caps under board

to better utilize space

Page 37: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

PCB Layout: Microcontroller

Unconnected pins

configured as outputs

and left floating

Page 38: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

PCB Layout: Peripherals

Mic & Audio Amplifier

Ultrasonic SensorInputs

Reset Circuit

SD Card & LCD Headers

GPS, Digital Compass, & PICKIT Headers

AnalogDigital

Page 39: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

PCB Layout: Peripherals

Separation of

analog & digital

interfaces

AnalogDigital

Page 40: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

PCB Layout: Peripherals

Analog and switching lines cross

at right

angles (2 cases)

AnalogDigital

Page 41: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

PCB Layout: Peripherals

Peripherals connected

through headers to preserve

board area & minimize

traces(9 headers)

AnalogDigital

Page 42: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

Software Design

Navigation Haversine Formula▪ Used to calculate great-circle distances

Only need three points▪ Robot position:▪ Target position:▪ North pole:

( , )r rR ( , )t tT ( , )n nN

Page 43: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

Software Design

2 2sin sin sin sin2 2

r th

2 arcsinc r h

n r n t r t

r = Radius of Earth

Page 44: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

Software Design

t r t r

m

Page 45: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

Completion Timeline

Week Date Task Notes

9 12-Mar Final Schematic/Layout

10 19-Mar Software Development Spring Break

11 26-Mar PCB Assembly

12 2-Apr PCB Assembly Complete External Software Complete

13 9-Apr Software Complete, Debug Embedded Software Complete

14 16-Apr Field Testing

15 23-Apr Field Testing

16 30-AprTesting Complete, Demonstration

Page 46: Bryan McDonnel Michael Mize Ryan Taylor Miles Whittaker

Questions?