Can we make our robots have a tug-of War? We will not stick to official Robot Tug-Of War rules, we will just have some fun finding out how to make a strong robot.

Robot Tug-of War.

What sort of robot would you use for a tug-of war? If we took the light sensor off our robot, we could use it, as shown below.

How would you program your robot – fast or slow – straight or crooked? Have a go with your robot now.

Robot Tug-of War Contests.

Some people have contest rules like these:-

If any part of a robot crosses the centerline, or any part comes off a robot, that robot loses that round.
After being started, a robot must wait at least 5 seconds before moving.
If, after 1 minute, no robot has crossed the centerline, the round is to be considered a draw.
A robot must win 2 out of 3 trials.
In the case of a draw, where neither robot is successful in pulling the other across the line, the winner is determined by holding a tie-breaking round. In this round, the winner is determined by measuring the distance of each robot from the centerline at the end of the time limit. The robot closest to the line loses.

But how you run your contests is up to you and your teacher/mentor – make up your own rules if you like!

Different Tug-of War Robots?

You could also build different types of Tug-of War robots that might be better than our present ones. Would your robot be better if you made it heavier or lighter? Would it be better longer or shorter? Would it be better wider or narrower? Would it be better taller or shorter? Would it be better with 1, 2 or more motors? Would the ones like those below be better? Would more or less wheels be better? In fact, do you need any wheels at all?

So many options and so much fun to be had…

Hints

Heavier Robots are harder for an opponent robot to pull over the line. If your robot use gears to make its wheels turn more slowly, this can also make your robot more difficult to pull over the line; to do this you would put a small gear on the motor axle, and a larger gear of the wheel axle. Sometimes using more than one tyre on an axle can make your robot more difficult to pull over the line; but this will depend on whether your competition is being held on a table-top or carpet. But have you talked to your teacher/mentor about whether your robot needs wheels at all?

Robot Tugs-of War on the Web?

You might also get some ideas from seeing some robot tugs-of war using Lego robots on YouTube, here, here, (interesting robots - but smashing the robots is NOT a good idea here) and here. Some big University Lego tug-of-war robots can be seen in action here.

There is also a 10 minute introduction to official Lego Tug-of-War contests here which includes discussion and demonstrations.

Mentor note: This Challenge is also available in 2-page Microsoft Word format - click here.