By Romain Chaumier, Šikula Robotics
This year’s French Robotics Cup took place on May 8-12, 2013. It’s a fun, scientific and technical challenge for robotics’ amateurs. The cup is organized each year by the city of La Ferté-Bernard and the Planète-Sciences association during the ARTEC (Arts and Technologies) festival. Each year, the cup has gathered more than 170 teams and 80 000 visitors during the event.
The challengers have to design and realize an autonomous robot, which have to follow the cup’s rules and be able to play matches. The robots face each other in a game in which they have to choose their actions by themselves (no pilot). The contest is suited for robotics passionate young teams or teams with an educative project. Matches confront two teams on a gaming table. The meeting is a good occasion for sharing knowledge.
This year, the theme was Happy Birthday to celebrate the 20th edition of the French robotics cup. The robots had to blow out the candles on the cake by pressing tennis balls in tubes, put cherry on the cake by sending ping pong ball in a small pan on the cake, open presents by tilting, make pyramids of cocktail glasses and the funny action : inflate a balloon.
Our association Šikula Robotik participated for its second year. Our team is composed of 6 people. The association presented 3 robots and 2 teams. The first team had 2 robots : the main robot had to do all the action except sending cherry on the cake because the secondary robot was dedicated to this action. The second team had for aim to build a robot during the event in order to prove that it’s possible to make a simple robot with low budget and little time.
As the theme changes every year, we have to make modifications each year, especially on the mechanics because the game actions are different. So we need to do prototypes and custom pieces. For these reasons we wanted to try 3D printing to make some parts fully adapted to our needs and are sometimes difficult to obtain by another technology. So this year we used a Printrbot Plus. Below, you can find some parts that were made with the 3D printer.
In order to avoid the opponent we used 4 ultrasonic sensors on the top of our robot. To fixed them we had to made a custom piece with different constraints : sensor should have a specific orientation to detect the largest possible area, anticipate access for cables and the support have to be adjustable in height. For this we made a custom printed piece. We designed it on 3D CAD software and made a piece that slides on 4 rods to be adjustable in height with holes for cables on the sides.
Another part that was made with 3D printer is the link piece between the propulsion wheel and the pulley. That part had to be the smallest as possible but had to be able to transmit the torque from de pulley to the wheel.
The robot has to know its position on the table and it didn’t have eyes like us to see where it is ! To know the position of the robot we use incremental encoder with a wheel. It will record the displacement of the robot (if the wheel made 1 turn, we know that the robot made 220 mm). So if we know the starting point on the table and the path taken, we know the actual location of the robot. To hold the encoder and to be sure that the wheel is always in contact with the table we made a connecting rod.
The French robotics cup is also a place for sharing knowledge. Our stand was accessible for visitors and many people stopped by to see our robot or to ask questions about 3D printing.
The 3D printer allowed us to explain how it works and sensitize the younger visitors to new technologies.
The French robotic cup allowed our team to talk about machines that are able to shake up our daily life. Beyond the technical and scientific aspect, it was an exchange of knowledge and skills. We could transmit our passion for robotics.
At the end of the competition, the theme for next year was reveled : Prehistobot. But the rules and the game action will be reveled at the end of September. We are already working on the rolling base of the robot to increase the displacement accuracy. The rolling base will be developed in aluminum, but to validate the principle we are making a prototype in 3D printing.