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Intelligent Vehicle for Reconnaissance (IVR)

Esteban Andrade & Juan Arana April 23, 2012

University of Florida Department of Electrical Engineering EEL 4924-Senior Design-Final Report

Instructor: Dr. Eric M. Schwartz

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Table of Contents Abstract ........................................................................................................................................... 4

Executive Summary ........................................................................................................................ 4

Introduction ..................................................................................................................................... 4

IVR System Block Diagram ........................................................................................................... 5

IVR System Flow Chart .................................................................................................................. 6

IVR System Hardware Design ........................................................................................................ 7

IVR Components ....................................................................................................................................... 8

GPS System ........................................................................................................................................... 8

Sonar Sensors ........................................................................................................................................ 8

CMUcam4 .............................................................................................................................................. 9

H-Bridge Motor Driver ........................................................................................................................ 10

7.2V Battery Recharging Circuit .............................................................................................................. 11

Controller System Block Diagram ................................................................................................ 12

Controller System Flow Chart ...................................................................................................... 13

Controller System Hardware Design ............................................................................................ 14

Controller Components........................................................................................................................... 15

LCD- ILI9320 ........................................................................................................................................ 15

XBee .................................................................................................................................................... 15

Joystick ................................................................................................................................................ 16

Responsibility Table ..................................................................................................................... 17

Gantt Chart .................................................................................................................................... 19

Parts List ....................................................................................................................................... 20

Electrical Characteristics .............................................................................................................. 21

Test Plan........................................................................................................................................ 23

Conclusion .................................................................................................................................... 23

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Table of Figures Figure 1: IVR System Block Diagram ............................................................................................................. 5

Figure 2: MCU2 Flow Chart ........................................................................................................................... 6

Figure 3: MCU3 Flow Chart ........................................................................................................................... 6

Figure 4: IVR System Hardware Design ......................................................................................................... 7

Figure 5: IVR System PCB .............................................................................................................................. 7

Figure 6: Ultimate GPS .................................................................................................................................. 8

Figure 7: UltraSonic Sonars ........................................................................................................................... 8

Figure 8: CMUcam4 ....................................................................................................................................... 9

Figure 9: CMUcam4 GUI ................................................................................................................................ 9

Figure 10: Motor Driver Schematic ............................................................................................................. 10

Figure 11: H-Bridge PCB .............................................................................................................................. 10

Figure 12: Recharging Circuit Schematic ..................................................................................................... 11

Figure 13 Recharging Circuit PCB ................................................................................................................ 11

Figure 14: Controller System Block Diagram .............................................................................................. 12

Figure 15: Controller System Flow Chart .................................................................................................... 13

Figure 16: Controller System Hardware Schematic .................................................................................... 14

Figure 17: Controller System Hardware PCB .............................................................................................. 14

Figure 18: ILI9320 ........................................................................................................................................ 15

Figure 19: XBee ........................................................................................................................................... 15

Figure 20: Joystick ....................................................................................................................................... 16

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Abstract The IVR’s primary function is to search and acquire the position of a desired target. The car will

be controlled remotely via a radio module. The user can drive the car and request a picture. Also, the

IVR will periodically update the user with GPS, obstacle avoidance (navigation) and image statistics. The

user will be able to control the IVR via a handheld device that can display target’s image, coordinates

(GPS data), obstacle avoidance, and image statistics.

Executive Summary The IVR is implemented with two ATxmega128 microcontrollers. The body of the car came from

a Remote control car and everything except for the steering servo was removed. The IVR communicates

with the steering servo via PWM. The H-bridge motor driver was designed in house. It requires four

PWM signals to operate the motor. The vehicle has an eighty-six-turn motor which did not originally

come with the car. The original twenty-turn motor that came with the car was replaced because it did

not allow the IVR to travel at a constant slow and easily controllable speed. In order to navigate and

track the object, three sensors are used: GPS, sonar, and CMUcam. GPS and CMUcam communicate via

UART and the sonar communicates via frequency modulated signal which is fed into the input capture of

the microcontroller. Sensor data is sent back to the controller using an XBee device through UART

communication. On the control, another ATxmega128 receives the data from the XBee and displays data

on an LCD. The LCD communicates with the controller via SPI. The controller also has a joystick to steer

and drive the car.

Introduction IVR’s primary function is to search and locate a desired object by color tracking. The main sensor

used in the IVR tracking protocol will be the CMUcam. CMUcam will provide the user with color statistics

which will allow the user to locate the target. Also, the user will be able to navigate through obstacles

and prevent from collisions with the assistance of the sonar and a built-in collision protection feature.

All the data processed in the car will be sent to the controller which will be display in a readable form.

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IVR System Block Diagram

Figure 1: IVR System Block Diagram

The IVR’s main purposes are to respond to the user’s commands and provide feedback to

the user. The IVR contains two ATxmega: MCU2 and MCU3. MCU2 receives the commands

from the controller. Depending on the command, it will either update the PWM registers or

pass data to MCU3. Also MCU2 is always keeping track of the distance between the car and

any other object. MCU3 will receive the command from MCU2 and will either acquire data

from CMUcam and/or update the controller.

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IVR System Flow Chart

Figure 2: MCU2 Flow Chart

Figure 3: MCU3 Flow Chart

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IVR System Hardware Design

Figure 4: IVR System Hardware Design

Figure 5: IVR System PCB

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IVR Components

GPS System

Figure 6: Ultimate GPS

Sonar Sensors

Figure 7: UltraSonic Sonars

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CMUcam4

Figure 8: CMUcam4

Figure 9: CMUcam4 GUI

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H-Bridge Motor Driver

Figure 10: Motor Driver Schematic

Figure 11: H-Bridge PCB

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7.2V Battery Recharging Circuit

Figure 12: Recharging Circuit Schematic

Figure 13 Recharging Circuit PCB

This recharging circuit is designed to charge a 7.2V Ni-MH battery up to the nominal voltage of 8.2V at a

rate of approximately 300mA. An operational amplifier was used as a comparator to compare the

voltage of the battery with the target reference voltage. If the battery has not been charged to the

desired voltage, a red LED will be on signifying the charging of the battery. Once the battery is fully

charged, the opamp will turn off the charging of the battery (and hence the red LED) and turn on a green

LED to signify completion.

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Controller System Block Diagram

Figure 14: Controller System Block Diagram

The microcontroller on the handheld control has few interfaces. First is with the XBee communication

device. The ATxmega128 uses UART to send and receive data. The data received from the car is

displayed on an LCD via SPI. Upon updating the LCD with data from the car periodically, the control with

then update the car with a stream of driving commands (speed and direction).

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Controller System Flow Chart

Figure 15: Controller System Flow Chart

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Controller System Hardware Design

Figure 16: Controller System Hardware Schematic

Figure 17: Controller System Hardware PCB

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Controller Components

LCD- ILI9320

Figure 18: ILI9320

XBee

Figure 19: XBee

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Joystick

Figure 20: Joystick

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Responsibility Table

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Gantt Chart

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Parts List

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Electrical Characteristics

Electric Characteristics

IVR Voltage 8.2V

IVR Current 1.82 A

Controller Voltage 9V

Controller Current 180mA

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Test Plan Most of the communication between the controller and IVR was tested with an open source terminal

emulator and an extra Xbee.

Conclusion Being able to experience the design cycle from beginning to end was very rewarding. It is

important to notice the basic intuitions that humans take for granted that are very challenging to

implement in a robot. Two challenges faced were getting the timing right between controller and IVR in

order to accurately communicate and acquiring the right pixels of a color in order to track it in a desire

environment.

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