Researchers from across Europe are being trained in Genoa, Italy, this month in advance of taking possession of their very own iCub: a robot designed to have the physical and sensory capabilities of a two-and-a-half year old child.

For the researchers involved, one crucial characteristic of the new robot is that both the hardware and software are open-source and designed for easy collaboration. Whether the researchers build better cognitive architectures, learning algorithms, sensors or limbs, once their work has been proved on the European Commission-funded iCub, it can be shared and used to improve the next generation of machines.

The finished iCub stands about as tall as a three-year-old and is designed to encourage interaction

Though not the first open-source robot, iCub underscores a trend that is poised to increase the productivity of artificial-intelligence (AI) researchers, in the same way the open-source movement has enhanced work in other sectors of design.

"Open-source is an open faucet in a desert," said Olivier Sigaud, a professor at the Institute for Intelligent Systems and Robotics in Paris.

There are two models for driving long-term progress in robotics: industrial and academic, said Giorgio Metta, an assistant professor at the University of Genoa and the Italian Institute of Technology who is among the leaders of the RobotCub Consortium. Industry is very well-organized and can devote effort and money to the field. Academia, though less structured, represents a large proportion of robotics researchers.

It is for the latter group that the open-source approach is so important.

"I'm perhaps too enthusiastic about it, but I see only advantages: better collaboration, reproducibility of results, shared debugging, faster improvement, etc.," Metta said. "For theoretical research, standard publication in scientific journals and at conferences is OK. For robotics, sharing code is better."

After Sony retired the Aibo, enthusiasts worked to build a new robot with open-source underpinnings. The New4LR (four-legged robot) is ready for RoboCup soccer

The conventional approach of using commercial robots has long caused problems for academics. They must sign limiting nondisclosure agreements to gain access to proprietary technology, and they may be prevented from going into low-level control code. Then there's the headache of discovering that a line is being discontinued. When Sony abandoned robotics in 2006, for example, many groups that had been using the company's Aibo robot as their primary research platform were left in the lurch.

Opening up AI

Open-source robots are not new. Long before Lego Mindstorms debuted 10 years ago as a kit available to the public, its predecessor was regularly used for teaching and research in universities across the globe. The open-source culture that grew up around the technology--not to mention its sheer flexibility, ease of use and low cost--made it extremely popular among academics.

Another project, OpenPINO, was more ambitious. A team at Sony Computer Science Laboratories, led by Aibo developer Hiroaki Kitano, created an open-source humanoid robot intended for the academic community. Unfortunately, OpenPINO did not reach many researchers, particularly outside of Japan. Whether that was for technical or price reasons is not clear, but Sony's subsequent departure from the field makes it a moot point.

Rather than focus on building robots, some researchers have tried to build systems that allow software, once written, to be shared across machines. One example is Tekkotsu, created at Carnegie Mellon University in Pittsburgh.

With 53 degrees of freedom, the iCub lets researchers test their theories about interaction and learning in humans

"Tekkotsu is intended to make it easy to develop sophisticated applications on mobile robots, by providing an extensive set of well-integrated primitives for perception, navigation, manipulation and control," said project head David Touretzky, a research professor of computer science at CMU. "We are seeking to change the way undergraduate computer science students are introduced to robotics. We believe that the best approach is to give students technically sophisticated robots and good high-level software tools, and then teach them how to use these tools creatively."

The Tekkotsu project earned Technical Innovation Awards in 2006 and 2007 at the Mobile Robot Competition and Exhibition, held during the annual meeting of the Association for the Advancement of Artificial Intelligence. Ironically, much of the initial work was done on the Aibo.

For instance, Spelman College used Tekkotsu on the Sony robot to compete in the RoboCup competition, and some of Touretzky's own students got an Aibo to act as a blackjack dealer. The Tekkotsu researchers are now working to support more hardware platforms and even to build their own hardware.

Another new open-source robot, the New4LR (four-legged robot), has been designed precisely to fill the void left by Aibo's departure. Priced at just under $5,500, the robot should be affordable for most universities. Its open-source underpinnings are among the ways the robot will contribute to the field, said Oskar von Stryk, a professor of computer science at the Technical University of Darmstadt, Germany, where the New4LR was developed.

"Modularity and reusability are required to enable the technological evolution of autonomous robots," von Stryk said. "In the long run, this is only possible with open software and hardware modules that enable an unlimited number of researchers and developers to share their particular contributions."

Enter the iCub

Beyond taking an open-systems approach, the iCub robot is designed around a very particular take on artificial intelligence. The designers eschewed a top-down approach to engineering specific desired behaviors, a strategy often identified with Japanese robotics. Neither did they design knowledge-based algorithms that are entirely abstract and are supposed to work regardless of the robot used (and that fail to address basic control and perception issues).