Issue 46


Octav Florescu
iOS Developer @Telenav

Vlad Tamaș
C++ Developer @Telenav

Robots are already part of our past, present and future. Although mass media is barely covering this, the same, or even less, can be said about the sports played by them.

Robot Sumo is such an example.

Played by two autonomous robots instead of humans, Sumo wrestling has become exciting and attractive for a wide range of people, both players and audience.

Figure 1

In the Japanese original rule, dating back to 1990, the battle took place on a black Dohyo of 154cm in diameter, having a white margin that indicates the border. (e.g. Fig 2)

Figure 2

The sumobots were limited to a 20cm x 20cm base square area, no height limit, and a maximum of 3kg in weight.

The game is based on honor and gentleman rules, so the competitors cannot intentionally harm the ring or their opponent.

Basics (Audience relevant)

The match starts at the judge's command and continues until a contestant wins the round. The sumobots have to apply various strategies for finding and then pushing their opponent out of the ring. The first one to leave the Dohyo area loses the round.

Robot Sumo is divided into classes, the most popular (and their limits) being:

Each class has its specific Dohyo:

The winner is usually decided out of a maximum of 3 rounds. As the sumobots are autonomous, each round lasts around 6-10 seconds.

Mega Sumobots have a speed of about 6 m/s.

Enthusiasts relevant

Creating a battle-ready Mega Sumo robot requires time and money, just as everything else. If you do not want to access your holiday funds, a search for sponsors is the alternative. Once the budget is decided, the robot can take shape.

According to Japanese ideology, the most important component of a robot is its blade, despite the European concept of building the robot starting from its strong motors.

The Oracle, our sumobot, tries to combine these two principles, by integrating the strongest Maxon motor, available on the market, and a custom-made steel blade.

Team members: Sofia Hopartean, Alexandra Hreniuc, Vlad Tamas, Octav Florescu, Alexandru Bondor

The typical sumo robot has a 45 degree-angled blade, ideally in the form of an ascending part of the Gaussian curve. The blade aims aims at reaching the area under the opponent and lift its tires from the Dohyo, thus making it powerless. (Fig 3)

Figure 3

The focus being innovation, we have come up with an unseen design for the front of the robot. (Pic 4)

Figure 4

The key feature of this approach is to take advantage of Physics by deflecting the opponent's sensors. Being as stealth as possible, the mechanism allows us to use the brute force of the Maxon motors, to push the enemy out of the ring.

When inventing a winning robot, it should not have any standard components. Everything has to fit, in order to create the robot's personality.

Magnets ensure that the sumobot stays firmly pressed against the Dohyo, increasing the friction and the pushing power. Magnetic force can reach values of up to 200 kg. Can you imagine the force needed to push such a robot out of the ring?

Figure 5

By adjusting the motor's specifications, the gear determines the power of the robot. Finding the perfect gear ratio implies complex calculations, as well as taking into account the tires' diameter, the motor's rotational speed and power, the batteries, and the magnets. The tires' diameter directly influences the torque. The voltage received from the batteries directly influences the motor's speed, so, providing an overvoltage to them is one of the most commonly used tricks in the business. Knowing that power is indirectly proportional to speed, the gear ratio can be decided upon.

The personalized chassis has to be made of materials that are tough enough to support the shock of the impacts, taken from the opponents, but light enough to keep everything under the limit of 3 kg. This constraint impacts the use of modern materials and technologies, such as 3D printing, carbon fiber, and other metal alloys.

From here on, all that needs to be figured out is how to make the robot smart by the use of sensors. The sensor range and response time are the key aspects when choosing them. The sensors have to be positioned in such a way that the robot will be able to see as far and as wide as possible.

All the electronical and mechanical parts must be brought together, by using microcontrollers. The last part of the flow is for the team to create the robot's personality: search, attack and defense strategies.

After putting all the pieces in place, testing brings everything to perfection. This includes strategies and hardware.

Everything must work together for the full Mega Sumo experience.

Watch your legs and keep your eyes wide open!