Held this summer in Graz, Austria, Robocup 2009 hosted an array of robots, from Aldebaran’s Standard Platform Nao to the custom-built Middle Size Robot League, where Team T’n’T took first place with its BlackFin-based robot.
Multiple robots hit the field in a variety of soccer team competitions. For example, the Middle Size Robot League uses a 70-cm ball and a field that’s 18 by 12 m. The teams have five autonomous robots. One is usually the goalkeeper.
Good lighting and a clean playing field are critical because colored boundary lines need to be recognized using image recognition. It’s a simple task for most people watching the game, but it’s quite a challenge for the robots themselves.
ARTICULATED ROBOT SOCCER
The Aldebaran Robotics Nao has essentially replaced the four-legged Sony Aibo robot dog that had been the mainstay for the top-end competition (Fig. 1). Each team uses the same 23-in., bipedal Nao, so software is the deciding factor.
The Nao can walk at 2.5 km/hour. It has 25 degrees of freedom, including five per arm and leg. Teams use custom patented servos because off-the-shelf units offere limited performance and aren’t packaged in sufficiently small sizes. Inside the Nao is a range of sensors, including a gyrometer and accelerometers. A 30-frame/s camera provides vision.
A pair of main processors controls a collection of 16-bit Microchip dsPIC microcontrollers linked via a pair of RS485 multidrop serial buses. This distributed architecture is hidden from most developers. Wi-Fi links the robot teams.
BUILDING A ROBOT SOCCER TEAM
The middle-size robot soccer platforms provide developers with a bit more hardware flexibility. Robot specifications are limited by size, so the processing capabilities are up to the designers.
Jonas and Benno Timmermann of Team T’n’T put their algorithms into Spoerle’s Embedded Platform Concept (EPC). The EPC has a 533-MHz BlackFin ADSP-BF527 from Analog Devices (Fig. 2). They took advantage of the uClinux software to build their system. Unlike the Nao with its standard distributed platform, Team T’n’T had to handle all its peripherals using the BlackFin, including the visual sensor.
Hardware design flexibility can be an advantage. Rolling robots simplify the hardware and software design, compared to articulated robots. Of course, there is a tradeoff versus the standard Nao platform since the middle-size robot software must target a specific platform. Still, it allows a team to learn not only about robotic software but hardware as well.
Additionally, there’s a human-size Robocup league. If that isn’t enough robot action for you, check out the FIRST Robotics and Best Robotics competitions (see “Volunteers Wanted For A Fair Affair And Robots Everywhere”). Like Robocup, there are many local competitions where you can get a closer look at the robots, their electronics, and their programmers.