Introduction to LEGO NXT robotics and Robot Sumo
Introduction to LEGO NXT robotics and Robot Sumo for CJ Chung Associate Professor of Computer Science Founder and Director of Robofest Lawrence Technological University
This program is possible thanks to: a grant from Detroit Auto Dealers Association (DADA) Charitable Foundation Fund, ¡ which is a fund of the Community Foundation for Southeast Michigan. ¡ ¡ For more details, check out a press release at: http: //www. ltu. edu/news/detail. asp? Content. Id=F 43 D 8217 -293 D-480 E-B 657 -54392 CB 1171 A
Schedule First Workshop Day (3 hours) ¡ Second Workshop Day (3 hours) ¡ Third Workshop Day (2 hours) ¡ Meetings with your school staff/teachers to improve your sumo. Bot (3 hours x 2 meetings suggested) ¡ Official Competition at your school to select one team to advance to the World Robofest Championship on April 26. General public to be invited. ¡
Workshop First Day (3 hours) Introduction to Robotics ¡ Introduction to Robofest and Robot Sumo ¡ Introduction to Lego NXT ¡ Introduction to NXTG ¡ Basic programs ¡ l l l Motors Wait Turns
Introduction to Robotics ¡ What is a true robot? l l ¡ autonomous robot with an on board computer Mechanical, electrical, and computational components Six fundamental components of a robot l l l A brain or brains – computer Body: physical chasses that holds other pieces Actuators: motors, hydraulic pistons, pneumatics Sensors Power sources Communication mechanism
What is Robofest? 100% Autonomous ¡ Affordable ¡ Challenging: Unknown problem ¡ No direct adult help allowed during the competition ¡ Qualifiers and a World Championship ¡ Various categories including Robot Sumo ¡ Two divisions: ¡ l l 5 th – 9 th grade: Jr. Division 9 th – 12 th grade: Sr. Division
Robo. Sumo Push the other robot out of the Sumo ring
Specifications Junior Division Senior Division Sumo ring diameter 77 cm (30 inches) 122 cm (48 in) Maximum robot mass 2 kg (4. 4 lbs) 1 kg (2. 2 lbs) Maximum robot 23 cm (9 inches) width and length 30 cm (11. 75 inches) Maximum robot height no limit 30 cm (11. 75 inches) Robot type Any; Lego Mindstorms or NXT any recommended.
Why Sumo? The most popular robot competition in the world ¡ Integrator in Science Education – Math, Logic, Computers, Mechanics, and Physics ¡ Good for rookie teams ¡ Fun Motivator ¡
Unknown Problem in Robofest Sumo How to start is unknown ¡ Need sensor(s) ¡ Teams must bring a computer to program the unknown parts ¡
Introduction to Lego NXT Brain – RCX micro computer ¡ Body: Lego Technic pieces ¡ Actuators: up to 3 motors ¡ Sensors: Light, touch, US, Sound, etc. ¡ Power source: 9 V (six AA batteries or rechargeable battery pack) ¡ Communication mechanism: USB or Blue Tooth ¡
Introduction to “SB 2 (Sumo Bot 2)” Left motor: A ¡ Right motor: C ¡ Touch: 1 ¡ Light: 3 ¡ Ultra Sonic (distance): 4 ¡
Introduction to NXTG Programming ¡ Please go through Getting Started and Software Overview after this class
First NXT program: Go forward for 2 sec. and stop ¡ ¡ ¡ Let’s name the program first Click on Go >> button You’ll see a programming palette (canvas)
First NXT program using SB 1: Go forward for 2 sec. and stop ¡ ¡ Click on Move button Drag and drop the move block to the canvas (2/3)
First NXT program using SB 2: Go forward for 2 sec. and stop ¡ Change parameters for the Move l l l Port Direction Steering Power Duration Next Action (3/3) Block Configuration Panel
How to run your first program (1/2)
How to run your 1 st program (2/2) If “Found New Hardware” pops up, just follow the instruction ¡ Click on “Download” button ¡ Recommended to un-plug the cable from the Bot ¡ Press the orange button 4 times (Turn on, My files, Software files, Run your program entitled go 2 stop) ¡
How to rerun the program Check the program name on the LCD ¡ Press the orange button just once again ¡
How to stop the program ¡ Gray button
First NXT Program: Go forward for 2 sec. and stop (Review)
Do not forget: Save your programs ¡ Meaningful file (program) names ¡ Use comments ¡
2 nd Program: Forward. Back 1. 2. 3. Go Forward 2 rotations Wait 3 seconds, then Backward 1 rotation
Go Forward 2 rotations, Wait 3 seconds then Backward 1 rotation – Forward. Back
Making Turns ¡ Turn left stop Left wheel ¡ Spin left Left wheel ¡ Right wheel Face left stop Left wheel Right wheel
Turn 90 Left – Using a Motor Block! ¡ ¡ ¡ Forward 2 rotations, Turn Left 90 Degrees, and Forward 2 rotations
Forward 2 rotations, Turn Left 90 Degrees, and Forward 2 rotations – Turn 90 Left
How do we make to turn 90 degrees? Timer? ¡ Trial errors ¡ Let’s do the math!!! ¡ l l l Width of the robot: 14 cm Diameter of the wheel: 5. 5 cm Perimeter of the wheel: 5. 5 cm x pi = 17. 27 Travel distance needed: (14 x 2 x pi) / 4 = 21. 98 cm 14 cm Number of rotations needed? 21. 98 / 17. 27 = 1. 2727
How about 180 degree turns using a motor block? Forward 2 rotations, ¡ Turn Right 180 Degrees, ¡ and Forward 2 rotations ¡ 14 cm What is the rotation value for the Motor Block? 1. 27 x 2
“Spin” 180 degrees using Move/Steering Forward 1 rotation, ¡ Spin right 180 degrees ¡ Forward 1 rotation ¡ Travel distance needed: (14 x pi) / 2 = 21. 98 cm 14 cm Number of rotations needed? 21. 98 / 17. 27 = 1. 2727
Spin 180 right
Class Challenge: A Simple Maze Start line box Place a business card as a target point to reach
Online Resources www. ortop. org/NXT_Tutorial: a great tutorial on how to program in NXTG ¡ nxtasy. org: with more information than you could ever want about LEGO robots and programming; a great place to ask questions ¡
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