Introduction to LEGO NXT robotics
and Robot Sumo
Workshop Day 3
CJ Chung
Associate Professor of Computer Science
Lawrence Technological University
Workshop Third Day
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Improved Sumo program
Mini Competition
Tips and Ideas to improve your Robot!
Advanced Topics in NXTG (optional)
Team Pictures
Planning
Review: Basic Sumo
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Repeat the following forever:
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Go forward until the edge
Backward slightly (in Big block)
Turn right
Problems?
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Touch sensor and Ultrasonic sensor were not used
Improving the Sumo program
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Introduce a parallel sequence beam for
touch sensor– whenever the bumper is
hit, change the direction
Introduce a parallel sequence beam for
US sensor– whenever it detects an close
object, go straight using full power
Introduce a random wait value for turning
Mini Sumo Competition
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With Unknown Problem:
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The robot must wait until touch sensor is pressed
Wait 5 seconds, then start to move
Team 1
Team 1
Team 2
Team 3
Team 4
Team 5
X
Team 2
Team 3
Team 4
Team 5
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Team Picture
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The team picture will be printed on your
personal certificate
Please submit the following for each
team:
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Team
Team
Team
Team
name
member first and last name
member grade
member gender
Program for the Mini Competition
Press “Shift” to connect parallel sequence beams
Using a random number for Move duration
Is this a perfect program?
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No, there are still some problems
One example:
• The robot detects the edge line.
• Move backward.
• Turn right around 90 degrees.
• Then the robot must see the outside
of the ring which is very dark!!!
Ideas to improve your SumoBot
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Improve (debug) your program!
Applying Theories learned in Physical
Science
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Mass, Newton’s laws
Friction
Gearing
Wheel size
Power level
Detecting the opponent (can be done later)
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Touch sensor
US sensor(s)
Ideas to increase weight of your Robot
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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
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Use rubber bands
Add more wheels later for Worlds
Gearing Ideas
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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?
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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!
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Default power level is 75%
Fully charge your battery!!!
How to check the voltage level?
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See the icon on the LCD
Changing the shape of the Robot
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Make it sturdy
Front part may need some changes (After
the school qualifier)
Height of the robot matters?
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Consider the “center of gravity”
Ideas using 2 Touch Sensors
A touch sensor –front left
Another touch sensor – front right
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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
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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 Robofest
(www.robofest.net) competition date at
your school
Note on “Switch”
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This 3 day workshop material did not
cover “Switch” block that is an important
part of programming
The sample sumo program using parallel
sequence beams can be rewritten using
switches (data-driven fashion)