Final Report Project Title: Lunabot

EEL 4924 Electrical Engineering Design

(Senior Design)

Final Report

24 April 2012

Project Title: Lunabot

Team Name: LunaRovers

Team Members:

Name: Matt Morgan

Name: Alexis Mesa Avila

Project Abstract:

Our project consists of building a mobile, autonomous robot capable of simulating a lunar mission. It

must be able to handle navigating through an area of obstacles with efficiency and a particular mission

in mind. Missions developed thus far include tracking particular objects designated by color or by size,

as well as pre-planning routes for the most efficient direction of travel. This report, in particular, focuses

on the electronic aspects of the design. Six Faulhaber DC motors along with six independent motor

drivers will be used for movement, as well as two analog servos for turning. Modes of both autonomy as

well as manual (remote) control are supported. Location awareness and obstacle avoidance will be

achieved with IR sensors as well as a Microsoft Kinect integrated with a small PC running Windows.

All other processing will be achieved on an Atmel Xmega microprocessor, which ultimately has enough

capability to support all of the necessary peripherals.

University of Florida EEL 4924—Spring 2011 25-Apr-12 Electrical & Computer Engineering

/14 Final Report: Lunabot

Table of Contents

Sections:

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

Project Features .........................................................................................................................................4

Technical Objectives .................................................................................................................................5

Primary Rover Objectives .........................................................................................................................5

Concept / Technology Selection ...............................................................................................................8

Project Architecture ..................................................................................................................................9

Timeline ..................................................................................................................................................10

Bill of Materials ......................................................................................................................................11

Responsibility Matrix..............................................................................................................................13

Appendix .................................................................................................................................................14



Figures and Tables:

Figure 1: Microprocessor Software Flow Chart .......................................................................................6

Figure 2: PC Software Flow Chart............................................................................................................7

Figure 3: Microprocessor PCB .................................................................................................................8

Figure 4: Motor Driver PCB .....................................................................................................................9

Figure 5: High Level Behavior and Integration ........................................................................................9

Figure 6: Gantt Chart ..............................................................................................................................10

Table 1: Bill of Materials ........................................................................................................................11

Table 2: Responsibility Matrix ...............................................................................................................13

Figure 7: Rover Side Profile ...................................................................................................................14

Figure 8: Rover Front Profile ..................................................................................................................14

Figure 9: Color / Size Detection Algorithm (Screenshot) ......................................................................14

Figure 10: Blob Depth Algorithm (Screenshot)......................................................................................14



Introduction:

The Lunabot project finds application in the domains of robotic vision, image processing, location

awareness, and autonomous decision making. The robot has to use the tools at its disposal to accomplish

a specific task such as route planning and/or color following. If at any time the robot malfunctions and

goes rogue, there is always a remote control option present to which currently utilizes the Gator Remote

Control, designed by Berny and Brenda Pazos.

The purpose of the project is to design a robot capable of performing the necessary tasks for a lunar

mission. Major milestones involved in this undertaking involve the design of the PCB, which will

contain the main processing unit as well as integrate the motor drivers and sensors, design the necessary

multiple power supplies, harness the Kinect's depth and color detecting qualities to ultimately integrate

them into the other path finding and avoidance capabilities of the IR sensors, and develop both hardware

and software support for the Gator Remote Control.

Project Features:

The primary electronic features associated with the Lunabot are as follows:

Six independent, customized motor drivers powering six independent motors via PWM.

Microsoft Kinect with integrated PC for robotic vision algorithms

o Range is between 800 mm and 4000 mm

o Programmed using Visual Studios 2010 and the C# programming language

Six separate analog IR sensors (ranging from 20 cm to 150 cm)

o Primarily for use when objects are too close for the Kinect to detect

Four separate power supplies:

o Lithium-Polymer (LiPo) (two 18 V - 5000 mAh) for motors

o Lithium-ion for PC

o Two Alkaline (8 packs) for both microcontroller and Kinect

Wireless remote control

o Utilizing Xbee communication and the Gator Remote Control

Atmel XMega128A1 microprocessor controlling six motors, two servos, IR sensing, and

communication with the Kinect.

o Programmed using AVR Studios and the C programming language

Speaker with amplifier to warn surrounding environment of reverse movement



Technical Objectives:

The main objective of our project is to design a robotic system capable of advanced image processing in

both a depth and color realm using a Microsoft Kinect. Several key technical objectives that led to the

accomplishment of this task are as follows:

The development of a suitable PCB for the Atmel Xmega processor that allowed enough of the

peripherals to be both broken out and utilized as well as a USB connection for serial

communication

The design of a LiPo power supply that can support all six of the motors that is separate from the

one used for the microprocessor and is further protected from an imbalance of charge (using

Schottky diodes)

The design of motor driver PCBs using motor driver integrated circuit chips that allow for a large

enough amount of heat dissipation

The utilization of the Kinect SDK to obtain raw depth and color information that could be further

used for more advanced image processing algorithms

Filtering algorithms

o Color / Size - uses RGB frames to detect a specified color for which the rover can follow

and can further be expanded to only choose objects of a specific size or of a specific color

and size

o Depth - uses depth data to sort of objects of similar depth and converts it to a RGB frame

based off three separate planes from the Kinect. It then filters the image and detects

different blobs at varying distance regions - can be used for intelligent route planning

The integration of the Xbee receiver with the microprocessor for remote operation

Primary Rover Objectives:

The primary objectives of the Lunabot rover are as follows:

Implement a desired image processing algorithm (color/size tracking and/or route planning using

depth data)

Autonomously roam while utilizing both the Kinect vision processing as well as IR sensor

reactions

Function properly with the Gator Remote Control

Allow for switching between autonomous mode and remote control with the Gator Remote

Control



Two separate programs will be running simultaneously to accomplish these tasks. The software flow

charts for the microprocessor program can be seen in Figure 1 below while the one for the PC program

(running the Kinect) can be seen in Figure 2 on the following page.

Figure 1: Microprocessor Software Flow Chart

initialize

signal start

joystick

command?

receive XBee byte

joystick mode

yes

yes

no

no

read IRs

read FTDI byte react

to IR? react to IR

react to byte and reply flush FTDI buffer



Figure 2: PC Software Flow Chart

initialize vision algorithm

initialize connection

wait for go signal

process Kinect data

send command byte

receive handshake

joystick or

stop

command?

suspend

no

yes



Concept / Technology Selection:

The Atmel Xmega microprocessor was chosen due to its high number of accessories and

peripherals as well as a convenient coding environment found in AVR Studios (the PCB can be

seen below in Figure 3).

Figure 3: Microprocessor PCB

The Microsoft Kinect was chosen due to its low cost implementation of both depth perception

(IR range finding capability) and a built in RGB camera

A PC was chosen to run the image processing algorithms due to its compatibility with the

Microsoft Kinect SDK due to its ability to run Windows 7

The 20-150 cm Sharp GP2Y0A02YK0F IR sensors were chosen to reinforce the capabilities of

the Kinect. The Kinect's range only goes down to 800 mm (or 80 cm) so the IR sensors make

sure to catch anything that the Kinect cannot

An FTDI chip was used for communication with the microprocessor due to the fact that the

laptop serial communication is referenced at 5 V while the microprocessor's is at 3.3 V. The

FTDI ultimately acts as a small, convenient level shifter.

The STMicroelectronics motor driver IC's were chosen due to their 24 V capabilities as well as a

reputation of low power consumption -- large heat sinks were added in the board as is seen in

Figure 4 on the next page.



Figure 4: Motor Driver PCB

A LiPo power supply was designed for the motors for longevity of use

The frame, accompanied by the servos, was previously designed for a similar purpose, so it was

ultimately utilized for this concept and design

Project Architecture

The high-level block diagram of the overall integration can be seen in Figure 3 below.

Figure 5: High Level Behavior and Integration

*http://www.microsoft.com/en-us/kinectforwindows/*



For location awareness, the rover uses the Kinect for color/size detection as well as depth sensing. It

communicates with the onboard PC which uses serial communication and the help of an FTDI chip to

talk to the microprocessor. Six IR sensors are also installed around the robot to aid in further obstacle

avoidance and collision prevention. The microprocessor must timeshare the commands from the PC and

obtaining readings from the IRs. The microprocessor further controls the servos for turning the robot as

well as the motors for driving it. These features along with the data received from the sensors constitutes

the autonomous functionality of the rover. A battery breakout containing Schottky diodes is provided for

the LiPo power supply to prevent reverse charging since the batteries are connected in parallel. The

motor driver PCBs further have a reverse battery protection as well to limit the effect of current spikes

and reverse voltage. An external Digital to Analog converter was added to feed data to an amplifier

allowing a beep to be initiated upon reverse movement of the robot. Finally, a universal remote (or in

particular the Gator Remote Control) can communicate to the microprocessor via an external Xbee

receiver for complete teleoperation.

Timeline:

Figure 6: Gantt Chart



Bill of Materials

Part Quantity Cost Total Cost Link Motor Driver

Motor Driver IC 6 10.95 65.7 http://www.pololu.com/catalog/product/1449/resources

MOSFET N-Chanel 6 1.14 6.84

http://www.mouser.com/ProductDetail/International-Rectifier/IRFR3707ZPBF/?qs=am%252bH1kEnjyYBgzBWhd%2fAXg%3d%3d

Resistors 0 0

1k 30 0.04 1.2

http://www.mouser.com/ProductDetail/Bourns/CR0603-FX-1001HLF/?qs=sGAEpiMZZMu61qfTUdNhG6LqqFhkr6pUTHpvs3m%2fzKg%3d

1.5k 6 0.05 0.3

http://www.mouser.com/ProductDetail/Bourns/CR0603-FX-1501ELF/?qs=sGAEpiMZZMu61qfTUdNhG6LqqFhkr6pUWApUCPPG%2fkI%3d

4.7K 12 0.06 0.72

http://www.mouser.com/ProductDetail/Bourns/CR0603-JW-472ELF/?qs=sGAEpiMZZMu61qfTUdNhG2nPoCjtvs%252bRuB5Lwxt%2fCj8%3d

5k Pot LAB 0 0

10k 6 0.05 0.3

http://www.mouser.com/ProductDetail/Bourns/CR0603-FX-1002ELF/?qs=sGAEpiMZZMu61qfTUdNhG6LqqFhkr6pUNCm4S5639HA%3d

100k 6 0.06

http://www.mouser.com/ProductDetail/Bourns/CR0603-JW-104GLF/?qs=sGAEpiMZZMu61qfTUdNhG6LqqFhkr6pUBHqvl3Un3Lw%3d

Capacitors 0 0

33nF 6 0.06 0.36

http://www.mouser.com/ProductDetail/TDK/CGJ5F2C0G1H333J/?qs=sGAEpiMZZMvQvaS66kI3Tg%2foFz%2fLwwgfWCbN%252bKS31%2fw%3d

1500uF (rated 24V) 6 2.68 16.08

http://www.mouser.com/ProductDetail/Cornell-Dubilier/AFK158M35P44T-F/?qs=sGAEpiMZZMtZ1n0r9vR22U6UGRWH4l0P6EVWmPRKHZk%3d

Diode 6 0.06 0.36

http://www.mouser.com/ProductDetail/NXP-Semiconductors/BZX84J-C27135/?qs=sGAEpiMZZMstCHp3EWKGl2O5SrBf5BzYLDIpi2uar%2fI%3d

Connectors 0 0

Female Crimps 4 5.25 21 http://www.pololu.com/catalog/product/1930

Crimp Housing 6 1.79 10.74 http://www.pololu.com/catalog/product/1920

T connectors 12 1.5 18 http://www.pololu.com/catalog/product/925

http://www.pololu.com/catalog/product/1449/resources

http://www.pololu.com/catalog/product/1449/resources





































http://www.pololu.com/catalog/product/1930





Screw Terminal 12 1.5 18 http://www.pololu.com/catalog/product/2440

Batteries 0

Lipo 6 64.95 389.7

http://www.ebay.com/itm/Thunder-Power-Pro-Lite-V2-4350mAh-5-Cell-5S-18-5V-20C-Lipo-Battery-/300648749768?pt=Radio_Control_Parts_Accessories

Xmega 0

Sharp IR Modules 6 14.95 89.7 http://www.pololu.com/catalog/product/1137

Microsoft Kinect 1 99 139.99

http://www.walmart.com/ip/Kinect-Sensor-w-Kinect-Adventures-Bonus-Game-Value-Bundle/20655933?sourceid=1500000000000003142040&ci_src=14110944&ci_sku=20655933

FTDI chip 2 1.95 3.9

http://www.mouser.com/ProductDetail/FTDI/FT221XS-R/?qs=Gp1Yz1mis3X50YdmZBKPIvG0uxBmgtd9

Capacitors 0

100nF 30 0.06 1.8

http://www.mouser.com/ProductDetail/TDK/CGJ4J2X7R1H104K/?qs=sGAEpiMZZMvQvaS66kI3Tg%2foFz%2fLwwgfaN7S%2fL4x5Ng%3d

10uF 8 0.06 0.48

http://www.mouser.com/ProductDetail/TDK/CGJ5L2X7R1A106K/?qs=sGAEpiMZZMvQvaS66kI3Tg%2foFz%2fLwwgfxwyVfQy6sv4%3d

4.7uf 4 0.06 0.24

http://www.mouser.com/ProductDetail/TDK/CGJ5L2X7R1A475K/?qs=sGAEpiMZZMvQvaS66kI3Tg%2foFz%2fLwwgfeGyPfqMjI1M%3d

Resistors 0 0 0

100 Ohm 4 0.05 0.2

http://www.mouser.com/ProductDetail/Bourns/CR0603-FX-1000ELF/?qs=sGAEpiMZZMu61qfTUdNhG6LqqFhkr6pUY56%252bhmeYKV8%3d

10K 2 0.06 0.12


Regulators 0

3.3 V Regulator 2 2.47 4.94

http://www.mouser.com/ProductDetail/National-Semiconductor-TI/LMS1587CS-33-NOPB/?qs=sGAEpiMZZMug9GoBKXZ759%2fWxdjGb5obExiilBzAsSY%3d

5 V Regulator 2 3.1 6.2

http://www.mouser.com/ProductDetail/National-Semiconductor-TI/LM1085IS-50-NOPB/?qs=sGAEpiMZZMug9GoBKXZ759%2fWxdjGb5ob9TexsLiBDtA%3d

Shipping mouser 15

Shipping pololu 15

Shipping Sparkfun 5

Total 834.43 Table 1: Bill of Materials






























Responsibility Matrix

Item Matt Morgan Alexis Mesa Avila

Kinect Research / Navigation / Programming 100% 0%

Atmel Programming 90% 10%

FTDI Interface 90% 10%

PCB Motor Driver Design 50% 50%

PCB µP Design 50% 50%

Power Supply Design 50% 50%

Audio Output and PCB Design 100% 0%

IR Sensor Integration 80% 20%

Gator Remote Control Interfacing 80% 20%

Physical Assembly and Integration 80% 20%

Testing 80% 20% Table 2: Responsibility Matrix



Appendix

Robot Pictures

Figure 7: Rover Side Profile Figure 8: Rover Front Profile

Kinect Image Algorithms

Figure 9: Color / Size Detection Algorithm Figure 10: Blob Depth Algorithm

Final Report Project Title: Lunabot

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