Autonomous Dual Navigation System Vehicle

Dmitriy BekkerSergei Kunsevich

Computer EngineeringRochester Institute of Technology

December 1, 2005Advisor: Dr. Roy Czernikowski

Project Design Review

CE Projects II – Rochester Institute of Technology

Outline

• Project overview– System description– Achieving objectives– Vehicle motors

• Detailed system view– Component interface– Operational boundaries– Sensor placement– User interface

• System analysis– GPS– Wireless

communication– Sensor concerns

• Where we stand now• Budgeting (key

components)

CE Projects II – Rochester Institute of Technology

Project Overview – System Description

• Autonomous Dual Navigation System Vehicle– A vehicle that can autonomously navigate itself to user specified

waypoints while reporting and avoiding obstacles on the way.

• Vehicle base is a 1:6 model of Hummer H2• Uses two systems for navigation

– GPS– Electronic compass and optical shaft encoder

• User interface from base station (through wireless connection)

• Vehicle can navigate without GPS (when no signal)• Obstacles detected with rotating ultrasonic range finder

CE Projects II – Rochester Institute of Technology

Project Overview – Achieving Objectives

• Moving to a destination– Determine angular orientation

(compass) and distance to destination

– Turn towards destination and start moving

• Tracking vehicle movement– With GPS (when available)– With compass and optical shaft

encoder• Obstacles

– Detected with ultrasonic range finder

– Need to research suitable obstacle avoidance algorithms

Electronic compass (Devantech CMPS03)

Optical shaft encoder

GPS (Garmin 15L)

Ultrasonic range finder (Parallax PING)

CE Projects II – Rochester Institute of Technology

Project Overview – Vehicle Motors

• The vehicle will move using:– One DC motor for forward / reverse motion of

the rear wheels– One servo motor to steer the front wheels

• The ultrasonic range finder will rotate using a second servo motor– Front facing– 180° rotation

CE Projects II – Rochester Institute of Technology

Detailed System Overview –Component Interface

GPSSensor

HC12

Forward/reversemotion motor

Sonar rangefinder

I2C

N

S

EW

Compass sensor

RS-232

Servomotorfor turning

PWMsignalwire

PWM port

Port A/B

Port A/BSerial port 1

Serial port 0

Port A/B

Shaft encoder

Timer port

Servomotor forultrasonic rangefinder rotational

base

Cellular phone

(modem)

RS-232

PWM port

CE Projects II – Rochester Institute of Technology

Detailed System Overview –Operational Boundaries

• For demo, the vehicle needs a flat surface with minimum or no surface particles (like snow, ice, rocks, etc)

• GPS capability can only be demonstrated outdoors• Indoors the vehicle can only navigate using compass and

optical shaft encoder• Compass is sensitive to magnetic fields, so vehicle should

be operated away from large metallic objects and high power electronics

• Obstacle placement constraints will be determined once a suitable obstacle avoidance algorithm is chosen

CE Projects II – Rochester Institute of Technology

Detailed System Overview –Sensor Placement

Servo motor

Ultrasonicrange finder

servo motorfor turning

battery packfor movement

motors

GPS receiver

N

SE

W

Digitalcompass

DC motor forlinear movement

Additionalbattery pack for

electronics

Cellular phone (modem)

HC12 Board

Shaft encoderfor linear

displacement

CE Projects II – Rochester Institute of Technology

Detailed System Overview –User Interface

X

X

N

S

W E

Heading

20°

Current Coordinates

LAT: dd.mm.secLNG: ddd.mm.sec

___________Next Waypoint_________

LAT: dd.mm.secLNG: ddd.mm.sec

20m

Mag. (m) Heading (°)

ADD

STOP START/RES.RESET

NavigationGPS

30°

Navigation GPS

Coordinates

Navigation GPS

REMOVE LAST

OPEN DESTINATION TABLE

Speed (km/h)

10

GPS System Status

ONLINE

Data Sent Data Received Timeout Obstacle

OPEN COLLECTED DATA TABLE

CE Projects II – Rochester Institute of Technology

System Analysis –GPS

• Horizontal accuracy is within 3m of geographic location (with WAAS)

• Minimum refresh rate is 1 sec• The speed of the vehicle must be

less then ~3m/s for most accurate tracking

• GPS will be configured to transmit geographical location message only

GPS (Garmin 15L)

CE Projects II – Rochester Institute of Technology

System Analysis – Wireless Communication

• Data transferred wirelessly from vehicle to base station via cellular telephone network

• Motorola E815 cell phone is connected to the MCU via a proprietary serial cable and null modem adapter

• Data calls are managed with standard serial AT commands

HC12 Microcontroller board

Null ModemAdapter

Base Station Computer

Telephone Lines

Motorola E815

CE Projects II – Rochester Institute of Technology

System Analysis – Sensor Concerns

• Electronic compass is very sensitive to magnetic deviations

• Optical shaft encoder needs 100% traction for accurate measurement

• Ultrasonic range finder has wide signal propagation (~50°)

Electronic compass (Devantech CMPS03)

Optical shaft encoder

Ultrasonic range finder (Parallax PING)

CE Projects II – Rochester Institute of Technology

Where we stand now

• Completed tasks– Researched and decided on a code development tool

(Embedded GNU)– Constructed ultrasonic range finder test setup and

developed driver code– Constructed electronic compass test setup and developed

driver code (I2C)– Researched and decided on a wireless communication

scheme– Constructed optical shaft encoder test setup and

developed driver code– Improved front wheel steering system on vehicle– Developed and tested cellular modem communication

scheme

CE Projects II – Rochester Institute of Technology

Budgeting –Key Components

• Garmin GPS 15L $53.95• Devantech CMPS03 Compass $50.45• Parallax PING Range Finder $31.94• HC12 MCU Board $99.00• RC Hummer H2 $68.99• Motorola E815 Cell Phone $269.99

• Estimate List Price: $595.41• Our Total Price: $271.31

CE Projects II – Rochester Institute of Technology

Questions?