Introduction to L2Bot

(

L

ow-cost

L

aptop ro

Bot

)

CJ Chung

Associate Professor of Computer Science Founder & Director of Robofest

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Software development has been focusing on non-mobile computers

Now laptops, notebooks are everywhere

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The idea

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There are four key advantages to using

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robots for K ~ PhD education • • • • robotics is multi-disciplinary, robots make abstract concepts concrete, robotics is hands-on, and students usually have higher motivation through robotics

L2Bot • • • • • • • • Low-cost Laptop roBot Born in Intelligent Systems and Robotics Lab at LTU Two motors and a webcam with a laptop as a single brain (No micro-controllers). Free sensors from the laptop!

Affordable (about $200 ~ $240 w/o labor) Flexible/Adaptable – Modifications are easy Expandable – Lego Mindstorms, NXTs or Handy Boards for motors and sensors Programming Language Independent Safe – Not too fast!

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L2Bot History • • The first one: 2002 C++

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2003

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2004

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Garmin GPS L2Bot Block Diagram for Extended L2Bot (2004) Main Control Module (PC) USB Hub Lego IR Tower Microcontroller (68HC11-Based Handy Board) Various Sensors & Servo Motors Manual Stop Switch Fuse (1 Amp) Battery 12V 7 amp Hr.

Motor Driver Board Left Motor Right Motor Web Camera 2 Wireless Joystick ER1 Arm Lego RCX

2005

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2006

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2007

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L2Bot Line Following Demo Video

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Features of L2Bot 2007 edition • • • • • Serial Port (cf. old: Parallel Port) Lighter Simpler Lower cost 100% Java

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2008

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Battery 12V 7 amp hr.

Fuse (1 Amp) Manual Stop Switch Main Control Module (PC) USB Hub Motor Driver Left Motor Board Right Motor (Web) Camera RF receiver Lego NXT Lego Sensors & Motors Joy Stick L2Bot

Six essential components of robots

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• • • • • • Brain Body Sensors Actuators Power source Communication mechanism

Brains (Processors) • • Your laptop, notebook Multiple NXTs

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LEGO NXT

L2Bot Processor:

32 bit ARM Atmel AT91SAM256, 50 Mhz

Memory:

64K Static RAM, 256K Flash 20

Robot Body • Designed and built from off-the-shelf components from: – Home Depot or Lowes – Jameco (online robotics store) – Digi-Key (online electronics store)

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Body: Drive Train and Gearing • • • Front-wheel drive 3-inch pivoting wheels - rotate freely on the axis in both directions One 3” Swivel Caster Wheel

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Actuators: Motors Torque @ Max. Efficiency (g-cm) Current @ Max. Efficiency (mA) Gear Case Size (Diameter x Length) (inch) Gear Ratio Motor Size (Diameter x Length) (inch) Shaft Size (Diameter x Length) (inch) Rated Voltage (VDC) Terminal Type Speed @ Max. Efficiency (RPM) 3200 82 1.5 x 0.7

100:1 1.3 x 1.0

0.2 x 0.5

12 Solder 60

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Actuators: Motor Control • • LoCoMoCo: An H-bridge - electronic circuit which enables DC electric motors to be run forwards or backwards Motor commands to robot sent through laptop RS 232 Serial port interface

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Actuators: Lego NXT Servo Motors

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• • • Each motor has an embedded rotation sensor 360 counts per rotation The counter can be incremented or decremented

Sensors • • • • Web cam(s) Laptop Microphone – Sound sensor USB Mouse for proximity Available LEGO NXT sensors – Default sensors by Lego.com, Legoeducation.com: – 3 rd party sensors: • mindsensors.com

• hitechnic.com

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chung NXT Sensors • • • • • • • • Light Touch Ultrasonic (Distance measurement) Sound (microphone) Rotation – embedded in the motors Timer – Internal sensor Received Bluetooth messages NXT buttons 27

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Available NXT 3 party sensors • • • • • • • •

EOPD (Electro Optical Proximity Detector )

Compass Sensor Acceleration / Tilt Sensor IRSeeker (135 degree view) Gyro Vision Subsystem Pneumatic Pressure Sensor Many more!

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Power Source • • • • • One 12V 7 Amp Hour battery for motors and motor drive board Can last for an hour Manual stop switches for battery power Laptop has its own rechargeable batteries which also provides power for the webcam NXT has its own (rechargeable) batteries – 9V

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Communication Mechanism • • • L2Bot can be connected to the network through the wireless card on the laptop NXTS provides Blue Tooth communication mechanism Microsoft Speech synthesis and recognition Engine is possible

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L2Bot Java Software Architecture Devices OS JVM DLLs with JNI Java APIs (JMF, javax.comm, etc) Applications

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(*) VB, C#, MSRS, and MSRS VPL version will be available in the near future

Performance Specifications Length Width Height Weight without laptop Weight distribution* (left/right/rear) Motor RPM Motor voltage Max speed Battery Life 14 in (35 cm) 16 in (41 cm) 9.25 in (25 cm) 10.5 lbs (4.8 Kg) 3lb / 3lb / 4lb (1.37Kg/1.37Kg/2Kg) 60 12 Volts .875 ft/sec (25.9 cm/sec) More than 2 Hour

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(*) To be updated

How to Use Your L2Bot • • • • • Charge your 12V battery – Do not charge more than 14 hours… – Use voltage meter to check, if fully charged Connect battery terminals Connect your laptop with the serial cable Run your program Turn on the switch • It is highly recommended to unconnected battery terminals after using it

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Tools needed to assemble your Robot • • • A screw driver (power drill) Wrenches: 3/8”, ½”, and 9/16” (or one adjustable one) 3/32 size L-wrench:

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L2Bot website • • • • • www.robofest.net/l2bot Software installation of for L2Bot Sample programs Videos Online books

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L2Bot line following video clip

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http://www.robofest.net/l2bot

Collegiate Competitions with L2Bot • • Fall Mini UC Robofest Mini UC

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Start 2007 Challenge End

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2007 Mini Urban Challenge Video

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2008 Challenge

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Fall 2007 Mini Urban Challenge

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Fall 2008 Challenge 3 ft

DEAD END L2Bot

Start 2010 Challenge

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Advanced Projects Based on the learning from L2Bot • • • • IGVC (Intelligent Ground Vehicle Competition) RoboCup DARPA TARDEC project

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Summary & Conclusion • • • • Robotics reinvigorates curriculum Robotics excites students Robotics encourages teamwork L2Bot has been a good tool for classes due to the following reasons: – Affordable, simple, light, extendable, and safe – Work at home

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