Introduction to LEGO NXT robotics and Robot Sumo

1
Introduction to LEGO NXT robotics and Robot Sumo

• Workshop Day 3
• CJ Chung
• Associate Professor of Computer Science
• Lawrence Technological University

2
Workshop Third Day

• Improved Sumo program
• Mini Competition
• Tips and Ideas to improve your Robot!
• Advanced Topics in NXTG (optional)
• Team Pictures
• Planning

3
Review Basic Sumo

• Repeat the following forever
• Go forward until the edge
• Backward slightly (in Big block)
• Turn right
• Problems?
• Touch sensor and Ultrasonic sensor were not used

4
Improving the Sumo program

• 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

5
Mini Sumo Competition

• With Unknown Problem
• The robot must wait until touch sensor is pressed
• Wait 5 seconds, then start to move

6
Team Picture

• The team picture will be printed on your personal
  certificate
• Please submit the following for each team
• Team name
• Team member first and last name
• Team member grade
• Team member gender

7
Program for the Mini Competition
Press Shift to connect parallel sequence beams
8
Using a random number for Move duration
9
Is this a perfect program?

• 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!!!

10
Ideas to improve your SumoBot

• Improve (debug) your program!
• Applying Theories learned in Physical Science
• Mass, Newtons laws
• Friction
• Gearing
• Wheel size
• Power level
• Detecting the opponent (can be done later)
• Touch sensor
• US sensor(s)

11
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

12
Ideas to increase friction of your Robot

• Use rubber bands
• Add more wheels later for Worlds

13
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

14
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

15
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

16
Changing the shape of the Robot

• Make it sturdy
• Front part may need some changes (After the
  school qualifier)

17
Height of the robot matters?

• Consider the center of gravity

18
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

19
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 Robofest (www.robofest.net)
  competition date at your school

20
Note on Switch

• 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)