Transcript Info Meeting for Robofest

Introduction to LEGO NXT robotics
and Robot Sumo – Sept 20, 2008
Lawrence Technological University
Douglas G. Czinder
IEEE SEM R&A Chairperson
[email protected]
Professor Keith Bozin
[email protected]
CJ Chung, Ph.D.
Associate Professor and Director of Robofest
[email protected]
This program is possible thanks to:


a grant from The Chrysler Foundation
the Southeastern Michigan Chapter of the
IEEE Robotics & Automation Society
Workshop Schedule – Sept 20, 2008

9:30
10:00
10:20
11:00
11:15

12:30 - 1:30









1:30
2:15
2:30
3:00
3:30
– 10:00
– 10:20
– 11:00
- 11:15
- 12:30
- 2:15
– 2:30
– 3:00
– 3:30
– 4:00
Continental Breakfast (provided)
Intro to Lego NXT & Robofest
Basic NXTG programming
Break
Programming with Sensors
Lunch (provided)
Programming with Sensors (cont’d)
Break
Basic Sumo Program
Improved Sumo Program
Mini Competition
Introduction to Robotics

What is a true robot?



autonomous robot with an on board computer
Mechanical, electrical, and computational
components
Six fundamental components of a robot






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:


5th – 9th grade: Jr. Division
9th – 12th grade: Sr. Division
RoboSumo
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)
1kg (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
recommended.
any
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, Ultrasonic, Sound, etc.
Power source: 9V (six AA batteries or
rechargeable battery pack)
Communication mechanism: USB or Blue
Tooth
Introduction to “SB2 (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 SB1: 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 SB2: Go forward for 2
sec. and stop

Change parameters for the Move






Port
Direction
Steering
Power
Duration
Next Action
(3/3)
Block
Configuration Panel
How to run your first program (1/2)
How to run your 1st 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
go2stop)
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
2nd Program: ForwardBack
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 – ForwardBack
Making Turns
(Instructor Slide)

Objective



Challenge the students to think about how a turn is made
Two ways to turn using one motor (demonstrate by turning with
your leg)
Demonstrate advantage of turning by spinning
stop

Turn left
Left wheel
Right wheel

Spin left
Left wheel
Right wheel

Face left
stop
Left wheel
Right wheel
Making Turns

Turn left
stop


Left wheel
Right wheel
Left wheel
Right wheel
Spin left
Face left
stop
Left wheel
Right wheel
Turn90Left – 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 – Turn90Left
How do we make to turn 90 degrees?



Timer?
Trial errors
Let’s do the math!!!



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
Programming with Sensors

Programming with





Touch Sensor
Light Sensor
Ultrasonic Sensor
Repeat
Basic Sumo Program
Start-Touch



Wait until the touch sensor is pressed;
Then start the robot to go forward
Stop after a second
Start-Light




Locate the robot in the middle of the ring
Wait until the light sensor detects very
bright (lantern) light
Then start the robot to go forward
Stop after a second
Start-Light
Stop-Touch


Go straight until the bumper is hit
then stop
Stop-Edge


Go straight until the white edge of the
ring
Then stop
Loop


To repeat a sequence of code
Until





Elapsed time
Number of repetitions
Sensor condition is met
Logic becomes true
Forever
Say “Yes” – 10 times
Make the robot move around in the
ring – Basic Sumo (Sumo0)

Repeat the following forever:



Go forward until the edge
Backward slightly
Spin right
Sumo0
First Sumo Competition


Some matches
Ask students to list ideas to improve the
Sumo robot
Improved Sumo Program




Improved Sumo program
Unknown Problem
Mini Competition
Tips and Ideas to improve your Robot!
Program for the Mini Competition
Press “Shift” to connect parallel sequence beams
Ideas to improve your SumoBot


Improve (debug) your program!
Applying Theories learned in Physical
Science






Mass, Newton’s laws
Friction
Gearing
Wheel size
Power level
Detecting the opponent (can be done later)


Touch sensor
US sensor(s)
Ideas to increase weight of your Robot




What is the max weight of each division?
Add more Lego technic pieces, if you have
some at home
Add Coins, Used Batteries, or others –
make a holder using cardboards
Put your team name on the robot. An
idea: make a team flag
Ideas to increase friction of your Robot


Use rubber bands
Add more wheels later for Worlds
Gearing Ideas



Use gear train to increase gear ratio
Considering resources, this is not allowed
for the school qualifier
The winner from the school qualifier may
consider this idea later
Changing Wheels?



Using bigger wheels
Considering resources, this is not allowed
for the school qualifier
The winner from the school qualifier may
consider this idea later
Make sure the Power!



Default power level is 75%
Fully charge your battery!!!
How to check the voltage level?

See the icon on the LCD
Changing the shape of the Robot


Make it sturdy
Front part may need some changes (After
the school qualifier)
Height of the robot matters?

Consider the “center of gravity”
Ideas using 2 Touch Sensors
A touch sensor –front left
Another touch sensor – front right



If left sensor is pressed – turn left and
push hard
If right sensor is pressed – turn right and
push hard
If both left and right sensors are pressed,
push straight hard
What is next? - Meet with your teacher at
least twice before the school qualifier




Improve your programs
Add stuff for the max possible weight for
your robot
Review what you have learned for the
unknown problem. If you do not solve the
unknown problem, you lose automatically
Signed Media Release form must be ready
before the qualifying competition date at
your school
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
End of Today’s Workshop
Contact us with any questions:
Douglas G. Czinder
IEEE SEM R&A Chairperson
[email protected]
Professor Keith Bozin
[email protected]
CJ Chung, Ph.D.
Associate Professor and Director of Robofest
[email protected]