DESIGN REVIEW

Autonomous Targeting Vehicle (ATV)Daniel BarrettSebastian HeningSandunmalee AbeyratneAnthony Myers

• Autonomous Wheeled Vehicle– Navigate, track, and follow targets– Wireless communication to enter waypoints

• Atom board with Wi-Fi, connection via remote desktop

• Uses GPS to navigate and determine current location• Avoid obstacles using range finders• Wheel encoders, compass, accelerometer

– Improved precision movements– “Dead reckoning”

• Webcam Feature– Used to focus on targets– In absence of GPS, users will click a target that the robot will navigate to

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PROJECT OVERVIEW

PROJECT SPECIFIC SUCCESS CRITERIA

1. An ability to determine location within 10 meters based on GPS data.

2. An ability to control the speed and direction of the motors on each side in order to move forward, backward, turn left, and turn right.

3. An ability to visually track and follow a target via webcam.4. An ability to detect obstacles, and determine their distance

with a sonic range finder.5. An ability to determine changes in position using wheel

encoders, an accelerometer, and a compass.

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MAJOR COMPONENT SELECTION (PAGE 1/4)

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• Freescale MC9S12C32 Microcontroller [x2]– Plenty of onboard memory (64K SRAM, 32K Flash)– Rationale for using two microcontrollers:

• More energy efficient compared to a single, larger microcontroller• Cost efficient (We already own four of them, development boards)• Two pulse accumulators are necessary for wheel encoders• 6 PWM channels are utilized

• 20-Channel EM-406A GPS– Built in antenna– 10m positional accuracy / 5m with WAAS– Used with GPS evaluation board (USB Connection)

• Ultrasonic Range Finder (Maxsonar-XL EZ3)– 0 to 765cm range with 1cm resolution– Operates between 3.3V and 5VDC– Easy data retrieval using ATD conversion

GPS

GPS Evaluation Board

Ultrasonic Range Finder

MAJOR COMPONENT SELECTION (PAGE 2/4)

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• Sharp Infrared Proximity Sensors (Long Range)– 5ft range at a supply voltage of 5VDC– Easy data retrieval using ATD conversion

• Triple-Axis Accelerometer (BMA180)– 4-wire SPI communication– Accurate to .244 mg (g = gravitational acceleration)– Operates at 3.3VDC (Logic level converter needed)

• Triple-Axis Magnetometer (HMC5843)– I2C communication interface– 7 milli-gauss resolution– Low current draw– Operates at 3.3VDC (Logic level converter needed)

IR Rangefinder

Accelerometer

Magnetometer

MAJOR COMPONENT SELECTION (PAGE 3/4)

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• L298 Motor Driver Dual H-Bridge (Solarbotics)– Up to 4A total output current

• All four motors use only 1.1A under full load

– Includes 5V low-dropout regulator– Schottky EMF-protection diodes

• Gear Head Motor (Lynxmotion)– Operates at 12VDC– Rotates at up to 200 RPM– 30:1 Gear Reduction Ratio

• Quadrature Motor Encoder (Lynxmotion)– 100 cycles per revolution– 400 quadrature counts per revolution

H-Bridge

Gear Head Motor

Motor Encoder

MAJOR COMPONENT SELECTION (PAGE 4/4)

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• Off Road Robot Tires– 4.75in diameter, 2.375in width– Made of durable rubber– Rims made of sturdy nylon material

• A4WD1 Chassis (Lynxmotion)– Premade, little assembly required– Aluminum structural components for durability– Laser-cut Lexan panels– Pre-constructed motor mount holes

• 12V NiMH Battery Pack– Made of ten SC4200mAh NiMH batteries– Can deliver up to 40A discharging current– Twice the run-time of a NiCd power pack

Wheels

Robot Chassis Kit

Battery Pack

PACKAGING DESIGN

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• Designed with a small footprint– Allows stealthy navigation in tight spaces– Adequate height for greater range of visibility– Durable ABS plastic body to conceal electronics

• Movement– Four large all-terrain wheels– Four high-RPM (200 RPM) motors

• Sensors– Range finders mounted on front and top– Others concealed in body– Webcam mounted on top

BLOCK DIAGRAM

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THEORY OF OPERATION (PAGE 1/7)(5V Power Supply)

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THEORY OF OPERATION (PAGE 2/7)(3.3V Power Supply)

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THEORY OF OPERATION (PAGE 3/7)(H-Bridge)

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THEORY OF OPERATION (PAGE 4/7)(Battery Charging Circuit)

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5V Regulator

THEORY OF OPERATION (PAGE 5/7)(Microcontroller Connections [µC 1])

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THEORY OF OPERATION (PAGE 6/7)(Microcontroller Connections [µC 2])

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THEORY OF OPERATION (PAGE 7/7)(Logic Level Translator)

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PCB LAYOUT (PAGE 1/6)(Design Considerations)

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• Large 7” x 7 7/8” board mounted on chassis• Analog compass and accelerometer far from motors• Clearance between h-bridge circuitry and microcontrollers• Reduce clutter

– Wire-to-Board connectors on the outer edge• Allows for clean, easy connection between PCB and

peripherals

PCB LAYOUT (PAGE 2/6)(Design Considerations)

• Traces– Power and ground: 40 mils– Logic Signals: 15 mils

• Mounting holes– Securely attach PCB to robot chassis– Coincides with mounting holes on the atom board

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PCB LAYOUT (PAGE 3/6)(Microcontrollers)

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PCB LAYOUT (PAGE 4/6)(H-Bridge)

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PCB LAYOUT (PAGE 5/6)(Battery Charging Circuitry)

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PCB LAYOUT (PAGE 6/6)

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SOFTWARE DESIGN

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• Microcontrollers (Embedded C)- Responsible for polling sensors and controlling servos and motors- Software is broken up into functional blocks

• ATD, PWM, SPI, SCI, RTI, TIM, GPIO– Functions are organized according to the specific peripheral used

• Initialization Routines for each block• One header file for all function declarations, type defines, macros

• Atom Board (C++)- Responsible for sensor fusion and navigation- Broken into functional blocks

• Kalman filter, Control system, GPS parser, Pathfinder, Object tracking, User interface

SOFTWARE DESIGN –Block Diagram

24Wheel Motor

Control

Sensor Polling

Servo Control

Sensor Fusion

Object Tracking

PID control system

SimulationPathfinder

Build obstacle map

Measurements

Estimated Obstacle positions

Motor inputs

DesiredTrajectory

Graph structure

Estimated Position

Motor inputs

User Interface

Choose Target

Target position

GPS parser

Position

Choose Destination

Display Video, Map, and Position

Video

Microcontrollers

Atom Board

Kalman Filter

SOFTWARE DESIGN –Block Diagram

25Wheel Motor

Control

Sensor Polling

Servo Control

Sensor Fusion

Object Tracking

PID control system

SimulationPathfinder

Build obstacle map

Measurements

Estimated Obstacle positions

Motor inputs

DesiredTrajectory

Graph structure

Estimated Position

Motor inputs

User Interface

Choose Target

Target position

GPS parser

Position

Choose Destination

Display Video, Map, and Position

Video

Microcontrollers

Atom Board

Kalman Filter

Camera Tracking

SOFTWARE DESIGN –Block Diagram

26Wheel Motor

Control

Sensor Polling

Servo Control

Servo Control

Sensor Fusion

Object Tracking

Object Tracking

PID control system

SimulationPathfinder

Build obstacle map

Measurements

Estimated Obstacle positions

Motor inputs

DesiredTrajectory

Graph structure

Estimated Position

Motor inputs

User Interface

User Interface

Choose Target

Choose Target

Target position

Target position

GPS parser

Position

Choose Destination

Display Video, Map, and Position

VideoVideo

Microcontrollers

Atom Board

Kalman Filter

Navigation

SOFTWARE DESIGN –Block Diagram

27Wheel Motor

Control

Sensor Polling

Servo Control

Servo Control

Sensor Fusion

Object Tracking

Object Tracking

PID control system

SimulationPathfinder

Build obstacle map

Measurements

Estimated Obstacle positions

Motor inputs

DesiredTrajectory

Graph structure

Estimated Position

Motor inputs

User Interface

User Interface

Choose Target

Choose Target

Target position

Target position

GPS parser

Position

Choose Destination

Display Video, Map, and Position

VideoVideo

Microcontrollers

Atom Board

Kalman Filter

Collect Data

SOFTWARE DESIGN –Block Diagram

28Wheel Motor

Control

Sensor Polling

Servo Control

Servo Control

Sensor Fusion

Object Tracking

Object Tracking

PID control system

SimulationPathfinder

Build obstacle map

Measurements

Estimated Obstacle positions

Motor inputs

DesiredTrajectory

Graph structure

Estimated Position

Motor inputs

User Interface

User Interface

Choose Target

Choose Target

Target position

Target position

GPS parser

Position

Choose Destination

Display Video, Map, and Position

VideoVideo

Microcontrollers

Atom Board

Kalman Filter

Estimate State of Robot and Obstacles

SOFTWARE DESIGN –Block Diagram

29Wheel Motor

Control

Sensor Polling

Servo Control

Servo Control

Sensor Fusion

Object Tracking

Object Tracking

PID control system

SimulationPathfinder

Build obstacle map

Measurements

Estimated Obstacle positions

Motor inputs

DesiredTrajectory

Graph structure

Estimated Position

Motor inputs

User Interface

User Interface

Choose Target

Choose Target

Target position

Target position

GPS parser

Position

Choose Destination

Display Video, Map, and Position

VideoVideo

Microcontrollers

Atom Board

Kalman Filter

Planning

Acting on Plan

SOFTWARE DESIGN – To be completed

30Wheel Motor

Control

Sensor Polling

Servo Control

Sensor Fusion

Object Tracking

PID control system

SimulationPathfinder

Build obstacle map

Measurements

Estimated Obstacle positions

Motor inputs

DesiredTrajectory

Graph structure

Estimated Position

Motor inputs

User Interface

Choose Target

Target position

GPS parser

Position

Choose Destination

Display Video, Map, and Position

Video

Microcontrollers

Atom Board

I2C Compass

Kalman Filter

PROJECT STATUS

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• Things accomplished– Communication with range finders, wheel encoders, accelerometer, GPS– Motor control based on commands through SCI– Camera tracking fully implemented– Sensor fusion, navigation, and control system tested in simulation

• Things to be completed– Communication with Compass ( ~ 1 week)– Communication between micros and Atom board (~ 1 week)– PCB layout testing and verification (~ 4 weeks)– Mount PCB, Atom board and sensors in/on robot (~ 2 weeks)

• Estimated projected completion– By the end of the semester

PROJECT TIMELINE

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Week # Milestone

Week 8 - Continue PCB design process - Verify functionality of compass & battery management system

Week 9 - Work on communication between Atom board and microcontroller - Design motor control algorithm - Produce Gerber files for PCB fabrication

Week 10 - Continue working on inter-system communication - Packaging design

Weeks 11-12 - Populate PCB one component at a time, test functionality

Week 13 - Improve algorithms as necessary to achieve desired functionality

Week 14 - Continue testing and verifying overall functionality of robot

Week 15 - Finalize design and packaging

Week 16 - Demonstrate final PSSC’s

Questions?

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