L 2 Bot Introduction to L 2 Bot
L 2 Bot Introduction to L 2 Bot (Low-cost Laptop ro. Bot) Bot CJ Chung Associate Professor of Computer Science Founder & Director of Robofest
L 2 Bot Software development has been focusing on non-mobile computers
Now laptops, notebooks are everywhere L 2 Bot
L 2 Bot The idea
L 2 Bot There are four key advantages to using robots for K ~ Ph. D education • • robotics is multi-disciplinary, robots make abstract concepts concrete, robotics is hands-on, and students usually have higher motivation through robotics
L 2 Bot • Low-cost Laptop ro. Bot • 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!
L 2 Bot History • The first one: 2002 • C++
L 2 Bot 2003
L 2 Bot 2004
L 2 Bot
L 2 Bot 2005
L 2 Bot 2006
L 2 Bot 2007
L 2 Bot Line Following Demo Video
L 2 Bot Features of L 2 Bot 2007 edition • • • Serial Port (cf. old: Parallel Port) Lighter Simpler Lower cost 100% Java
L 2 Bot 2008
L 2 Bot 08 Block Diagram
L 2 Bot Six essential components of robots • • • Brain Body Sensors Actuators Power source Communication mechanism
L 2 Bot Brains (Processors) • Your laptop, notebook • Multiple NXTs
L 2 Bot LEGO NXT Processor: 32 bit ARM Atmel AT 91 SAM 256, 50 Mhz Memory: 64 K Static RAM, 256 K Flash 20
L 2 Bot Robot Body • Designed and built from off-the-shelf components from: – Home Depot or Lowes – Jameco (online robotics store) – Digi-Key (online electronics store)
L 2 Bot 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
L 2 Bot Actuators: Motors Torque @ Max. Efficiency (g-cm) 3200 Current @ Max. Efficiency (m. A) 82 Gear Case Size (Diameter x Length) (inch) 1. 5 x 0. 7 Gear Ratio 100: 1 Motor Size (Diameter x Length) (inch) 1. 3 x 1. 0 Shaft Size (Diameter x Length) (inch) 0. 2 x 0. 5 Rated Voltage (VDC) 12 Terminal Type Solder Speed @ Max. Efficiency (RPM) 60
L 2 Bot Actuators: Motor Control • Lo. Co. Mo. Co: 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
L 2 Bot Actuators: Lego NXT Servo Motors • Each motor has an embedded rotation sensor • 360 counts per rotation • The counter can be incremented or decremented
L 2 Bot 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
L 2 Bot NXT Sensors • • chung Light Touch Ultrasonic (Distance measurement) Sound (microphone) Rotation – embedded in the motors Timer – Internal sensor Received Bluetooth messages NXT buttons 27
L 2 Bot 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!
L 2 Bot Power Source • One 12 V 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 – 9 V
L 2 Bot Communication Mechanism • L 2 Bot 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
L 2 Bot Java Software Architecture Devices OS JVM DLLs with JNI Java APIs (JMF, javax. comm, etc) Applications (*) 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 (*) To be updated 14 in (35 cm) 16 in (41 cm) 9. 25 in (25 cm) 10. 5 lbs (4. 8 Kg) 3 lb / 4 lb (1. 37 Kg/2 Kg) 60 12 Volts. 875 ft/sec (25. 9 cm/sec) More than 2 Hour L 2 Bot
L 2 Bot How to Use Your L 2 Bot • Charge your 12 V 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
L 2 Bot 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:
L 2 Bot website • • • www. robofest. net/l 2 bot Software installation of for L 2 Bot Sample programs Videos Online books
L 2 Bot line following video clip http: //www. robofest. net/l 2 bot
L 2 Bot Collegiate Competitions with L 2 Bot • Fall Mini UC • Robofest Mini UC
L 2 Bot 2007 Challenge Start End
L 2 Bot 2007 Mini Urban Challenge Video
L 2 Bot 2008 Challenge
L 2 Bot Fall 2007 Mini Urban Challenge
L 2 Bot Fall 2008 Challenge 3 ft DEAD END
L 2 Bot 2010 Challenge Start
Advanced Projects Based on the learning from L 2 Bot • • IGVC (Intelligent Ground Vehicle Competition) Robo. Cup DARPA TARDEC project L 2 Bot
L 2 Bot Summary & Conclusion • • Robotics reinvigorates curriculum Robotics excites students Robotics encourages teamwork L 2 Bot 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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