"ZiPcIrEk" Sumo robot

“ZiPcIrEk” was the one of the first major embedded projects I had been involved in. This project started during the second year of my studies and lasted for two years. There were a number of people involved, as this project required skills in multiple fields (mechanics, motors etc.). I was responsible for embedded software and CPU board design.

“ZiPcIrEk” is a SUMO class (3kg, 20 x 20 cm) mobile robot that used to represent the Student Scientific Association of Robotics “KoNaR” on the “CybAiRBot” robot competitions in Poznan.

Fig 1: Photo 1

The robot’s primary goal is to push the opponent outside the ring, called “dohyo”, like in real sumo fights. Robots must be fully autonomous and comply to various other game rules.

The robot is built on a metal frame, which holds two DC motors with planetary gear-boxes. The wheels turn around the motor, powered by a belt, to split the power to the two wheels on each side. This robot is, therefore, a (2,0) class one. The metal frame also holds a set of Li-Pol batteries. On the front side of the robot there are two flaps, moved by RC servos, intended to lift the attacking opponent and remove its ability to move. The robot is enclosed in a durable case with a LCD and an In System Programming connector on the back side.

Fig 2: Robot diagram

On the top of that, there is a place for electronics, MOSFET H-Bridges and CPU board mainly. The CPU, that controls the whole robot, is NXP’s ARM7 LPC2148. Around the metal frame, on each side except the front one, there are IR 36 kHz sensors, used to early detect the opponent behind or on either side. On the bottom side of the metal frame there are four IR binary sensors, one in each corner, used to detect if the robot has crossed the white line that marks ring’s perimeter. The most important is the turret on the top that has an IR range finder (Sharp) and a ultrasonic one (Parallax). The turret can rotate on a small RC servo and by doing this it scans the surrounding for the opponent’s robot. The embedded software uses Rodney Brooks’ Subsumption architecture approach to control the robot. In this case, for example, crossing the ring’s edge event has much more importance for the robot than the intention to attack the opponent. In such layered behavioral way the robot controls its actions.

The robot took its chances three times on “CybAiRBot” Sumo Robot contest. Unfortunately, it had never won anything. However, I think of this project as a first remarkable embedded experience and I've learned a lot.