Introduction to LEGO RCX robotics and Robot Sumo

Workshop Day 3

CJ ChungAssociate Professor of Computer ScienceLawrence Technological University

Workshop Third Day

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

Review: Basic Sumo

Repeat the following forever: Go forward until the edge Backward slightly (in Big block) Turn right

Problems? Same behavior all the time! Touch sensor was not used

Improving the Sumo program

Introduce a random wait value for turning Introduce a touch sensor watcher –

whenever the bumper is hit, change the direction

Improved Sumo Program

If your opponent is pushingYour back, then change yourdirection

Random between 0.5 ~ 1.2 seconds

Mini Sumo Competition 1

Without Unknown Problem Every team will compete with every other team Team picture time!!!

Team 1 Team 2 Team 3 Team 4 Team 5

Team 1 X X X X X

Team 2 X X X X

Team 3 X X X

Team 4 X X

Team 5 X

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

Mini Sumo Competition 2

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

You cannot use the previous way using a touch sensor watcher! Why? Whenever the touch sensor is pressed, the robot will spin…

Team 1 Team 2 Team 3 Team 4 Team 5

Team 1 X X X X X

Team 2 X X X X

Team 3 X X X

Team 4 X X

Team 5 X

Better Program for the competition 2

A nested loop Repeat Until that

will terminate the loop immediately when the termination condition is met

UnknownProblemsolution

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!!!

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 IR and light sensor

Ideas to increase weight of your Robot

What is the max weight of each division? Add more Lego blocks, 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!

RCX power level: 1 ~ 7 Voltage of your batteries should be

around 9V How to check the voltage level

In RIS, click on Settings LTU will provide fresh batteries for all the

teams on the competition day

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 leftAnother 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

Implementing Proximity Sensor to detect opponent (optional)

Use a Lego Light sensor and Infrared message sending capability of RCX

RCX is continuously sending IR messages Using another light sensor facing forward,

measure fluctuations in the light intensity that is reflected from objects

The higher the fluctuation, the closer the robot is to an object

How to detect the light fluctuation??

You need to store previous sensor reading(s)

Compare with current reading If the difference is more than threshold

value, some thing is in front!

preval becomes the value of Light 3

preval = preval + 3

If the current light sensorreading is greater than (previous value + 3), then some thing is close.

Sumo with proximity sensor

Repeat forever: Scan until find the opponent Go forward until the edge Backward slightly Turn right

My Blocks (optional topic)

Opening a saved program (optional)

Never use File | Open! There is a bug involving MyCommands

Use Main Menu | Program | Vault