Welcome to the SevenOakMiddle School
LEGO© NXT – “Doyho of Dreams”
Sumo Challenge
A Brief History of Sumo:
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Sumo (,Sumō) is a competition contact sport where two wrestlers called rikishi face off in a circular ring area called a dohyō. Sumo probably originated in China during the Han Dynasty. The first time a Sumo-like wrestling bout occurred in Japan was in 453, when Chinese envoys performed (Suwu) at the funeral ceremony of Emperor Ingyō. The sport continued in China for some time. The classic Chinese novel Water Margin, dating in written form from the 16th century but based on much older folk tales, described the performance of (Sumo) during the much later Song Dynasty.
The sport is popular in Japan and is surrounded by ceremony and ritual. The Japanese consider Sumo a gendai budō: a modern Japanese martial art, even though the sport has a history spanning many centuries. The Sumo tradition is very ancient, and even today the sport includes many ritual elements, such as the use of salt for purification of the doyho –
a ritual from the days Sumo was used in the Shintoreligion.
The Challenge:
Build a Sumo robot using only the parts in one standard LEGO NXT set #9797 and/or one LEGO NXT Educational Resource set #9648.
The Rules:
This event is a round-robin tournament, with head-to-head play. The goal is to push the opponent out of the raised 3’-diameter circle dohyo– refer to dohyo illustration on page 4. The robots are placed diametrically opposite each other on the dohyo, within an inch of the edge, facing any direction of the competitor’s choosing. There is a 2-inch wide black warning zone at the perimeter of the dohyo to help robots see if they are near the edge. If a main component (any component of your robot connected to the NXT) of a robot makes contact with the surrounding surface, outside the dohyo, the opposing robot is declared the winner of that round.
Robots must be completely independent once they have been started. Once the judge indicates the start of the round, competitors press the ‘run’ button on their robots. A robot’s driving wheels must stand still for 5 seconds before moving. Robots have two minutes to push their opponents off the dohyo.
Robots are not allowed to intentionally damage each other. Any robot which, in the opinion of the judges, intentionally damages another robot will be disqualified from the competition. In the event that a robot becomes accidentally disabled in the course of a round, the owner of that robot may elect to concede the round to avoid further damage to the robot. In the case that both robots had become accidentally disabled, the round may be re-started by the judge, with a one-minute delay for minor repairs. If a robot is not ready to compete in one minute, it will automatically concede the round. All decisions of the judge are final.
Scoring is as follows:
Robots will be paired off in a round-robin tournament fashion. A robot will receive two points for each round that it wins, and zero points for each round that is lost. A tie will result in each robot receiving a single point.
Besides the points won in the tournament, there will be two types of bonus points that will be given out. A single bonus point will be given (once) to each robot that actually moves around the dohyo. In the event of a tie for first place, a single bonus point will be given to one of the tied robots by audience vote for their favorite. Should two robots become “locked in battle,” the judge will wait for a period of at least 30 seconds before asking each competitor if they wish to concede. If neither competitor concedes, the judge reserves the right to end the round and have each competitor repeat the round.
The winner is the robot with the highest number of points.
Building restrictions:
Your robot must fit in a 10” by 10” square. There is no height restriction. Only the pieces that come in sets
#9797 and #9648 may be used. No other LEGO parts (except for batteries) may be used. You may not modify pieces in any way. Only standard building techniques are allowed. No gluing, taping, etc.
The robot must stay in one piece at all times. If a part is lost, it will remain on the dohyo until the end of the round.
The Dohyo:
The dohyo will be a 3’ diameter circle, completely white, except for a 2” black line around the edge. The dohyo surface is approximately 3/4” above the surrounding surface.
Robot placement is one inch away from the edge, which means at least a small portion of the robot will overlap the black edge. Robots will be placed on the dohyo by their owners - but the judge will make sure that they are directly opposite each other on the dohyo.
The LEGO© NXT Sumo Dohyo
At The Competition:
Each robot will be given a chance to compete against each other for a two minute round. The Judge will announce which robots will be next. Participants must be ready with their robots when the Judge calls their team number or concede the round.
Since the robots must be placed within an inch of the edge of the dohyo, and there is a 2” wide black circle, be aware that this means part of your robot will be on the black edge. This may impact the way you program your robot if it uses a light sensor to detect the edge.
After the main event, there will be a chance for all the robots to compete against each other at the same time (space allowing). This will be just for fun.
Some Tips:
There is only one type of wheel in the NXT set. Make the best use of them. There are three motors in the NXT set. While the extra weight will be enough of a reason to put it on your robot, try thinking of something useful to use it for!
Don’t forget to do the five-second pause before your robot starts moving.
The ultrasound sensor may seem like a great way to find your opponent, but be aware that there are spectators standing around the dohyo that may be closer to your robot than your opponent’s robot, and your opponent may also be using an ultrasound sensor. Both of these scenarios may possibly interfere with your light sensor’s readings.
While the physical parts used to construct your robot must be what comes in the NXT set(s), you may use whatever firmware or programming language you wish. You are not being restricted to using the firmware that the NXT was shipped with, or the NXT-G programming language.
Fine Tuning:
The Judge reserve the right to make minor changes to the dohyo or rules before or during the event. All teams will be made aware of any changes to the rules.
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