RoboCup was started in 1997 by a group of Artificial Intelligence and Robotics researchers with the following grand challenge, to be achieved by 2050 [9]: “to build a team of robot soccer players, which can beat a human World Cup champion team.” Since then, RoboCup Federation1 established itself as a structured organization and as one of the major events in the research field of Artificial Intelligence and Robotics. A quote from the website of the RoboCup Federation, best describes its objective.
a 18 m x 12 m field using a standard yellow or orange size 5 soccer ball. Here local perception requires sensor fusion as well as distributed approaches to robot coordination. Standard platform league is currently played with the Aldebaran NAO humanoid robots (formerly with the Sony Aibo), with two teams of 5 robots playing in a 9 m x 6 m field using an orange street hockey ball. In this league, in addition to the issues of the mid-size league to be addressed on a more challenging platform, the interaction between perception and action plays a critical role. Finally, the humanoid robot leagues (kid, teen and adult sizes), playing in a field similar to the one used in the Standard platform league, encompass all of the above mentioned issues, on top of a dedicated hardware development.
The second main section of RoboCup competitions targets systems with a more direct impact on our society. RoboCup Rescue is focussed on robots supporting human rescuers in the aftermath of disasters (e.g. Fukushima nuclear accidents or L’Aquila earthquake). This section includes both 2D and 3D simulated leagues as well as a main robot league, where robots perform several rescue tasks in arenas defined by the National Institute of Standards and Technology (NIST). RoboCup@Home addresses the development of robots that interact with humans helping them in home environments. The competition is performed in an arena reproducing an apartment with typical layouts and furniture, that is not known before-hand by the participating teams. Moreover, some test are executed in the public space of the main venues hosting the event, as well as in real restaurants, shopping malls nearby. Finally, more recently, RoboCup@Work has been set up as a league aiming at a new generation of industrial robots. In this league mobile manipulators are used for executing tasks related to manufacturing, automation, and general logistics.
The third section of RoboCup is dedicated to competitions among juniors. RoboCup Junior is an educational initiative for students up to the age of 19, providing a new and exciting way to understand science and technology through hands-on experiences with electronics, hardware and software.
In this paper, we overview the achievements of the group at Sapienza first in terms of participation and results in the competitions and then in terms of research contributions. We conclude by discussing the impact of RoboCup@Sapienza and by providing a retrospective analysis. 2
The Italian community joined RoboCup since its first edition, and our research group at Sapienza University of Rome, in 1998. Since then, we participated in RoboCup competitions, first within the ART national Italian team2 and from 2001 as the SPQR team3. Figure 1 shows the evolution over the years of the robotic platforms used for the soccer competitions, moving from wheeled robots, to four-legged and finally to small humanoid robots; while Figure 2 shows rescue and @Home robots.
Moreover, Daniele Nardi is currently President of the RoboCup Federation (since 2011), and he has been Vice-President (2008-2011), and Trustee (since 2003). Luca Ioc
3 spqr.dis.uniroma1.it chi is Trustee (since 2013), formerly Executive for the RoboCup@Home league. They also contributed in the organization of scientific events, (e.g., co-chairs of RoboCup Symposia, workshops in international conferences, special issues in AI and robotics journals), as well as in the organization of regional competitions (such as Mediterranean Open 2010 and 2011, RomeCup, etc.).
RoboCup was brought to the attention of the Italian Artificial Intelligence community by Luigia Carlucci Aiello and by Enrico Pagello, who organized a well attended workshop in the Fall 1997. After that a joint project ART (Azzurra Robot Team) (Figure 1 a)) [11, 12] was sponsored by Consorzio Padova Ricerche and supported by the Italian National Research Council. Daniele Nardi was the CT (Technical Coordinator) of the project. The first kicks to the ball by ART robots started in the Spring 1998, and the first participation in RoboCup was in 1998, Paris. In 1999, at JCAI Stockholm, ART obtained the second place in the mid-size league. The project ended in 2000 after winning a European championship in the Netherlands, and participating in RoboCup 2000 in Melbourne.
In 2000, the first SPQR (Soccer Players Quadruped Robots) team from Sapienza, entered the Sony Aibo league (Figure 1 b)), obtaining the fourth place. Since then, SPQR participated in the league till 2007, with different generations of AIBO robots (Figure 1 c)), reaching the quarter finals and developing several technical contributions, including the pass that won the “Best Demo” Award at AAMAS 2008 [13].
In RoboCup 2003, Padova, SPQR joined the new RoboCup Rescue Competition. SPQR then participated both in the Real Robot Rescue League (Figure 2 a)) and in the Virtual Robot Simulation League, building on the results achieved through a collaboration with the Italian Firemen Dept. In the Virtual Robot Simulation League SPQR team obtained the 3rd place in 2007 and won the Technical Challenge for the Human Robot Interface in 2009. Moreover, during RoboCup 2009, members of the SPQR team made the first demonstration in RoboCup Rescue with quadrotors.
In RoboCup 2006, Bremen, we obtained the third place in the RoboCup@Home league, based on the platform developed within RoboCare4 (Figure 2 b)), the first Italian Project addressing the use of robots in a home environment to help the elderly people.
Since Robocup 2008, Suzhou, China, SPQR participated in the NAO humanoid league (Figure 1 d)), also teaming up with Univ. Santiago, Chile (2010). Worth mentioning is the first goal ever scored in the humanoid competitions with a back-kick. This year, SPQR won the Iranian Open, and obtained the third place in the German Open. In the last RoboCup in Eindhoven, SPQR was eliminated at the end of the second phase, because of the goal difference, after winning four games in a raw and loosing only the last one! 3
Our participation in RoboCup has been motivated in the first place by the research challenges put forward by the competitions. Our experience in mid-size league focussed on two topics: localization and cooperation. Initially, we looked at specialized methods
for localization that are applicable in RoboCup by looking at the lines of the soccer field [7]. After this initial work, localization and SLAM (Simoultaneous Localization And Mapping) have become one of the key research lines in our group. Cooperation among robots is needed in robot soccer and achieving it in a national team poses outstanding technical and scientific challenges. ART has been the first example of national team, and the key feature for success was the ability of the robots to cooperate through a simple, but effective approach, based on dynamic task assignment [4, 8], that afterwards has been a minimal prerequisite for all robot soccer teams. Cooperation and coordination became another research line in our group. We have then developed multi-robot systems for a variety of applications, including exploration and surveillance.
One of the most important abilities for soccer robots is understanding the situation through on-board sensors, in particular vision. An important challenge is thus real-time image processing and understanding with limited computational power. In this context, we developed an efficient method for color segmentation [6], that provides increased robustness to variable illumination conditions. Moreover, analysis of RGB-D data of cameras looking at the soccer field has been used to estimate the ground truth pose of the robots and the ball, useful for many evaluation tasks [14].
The results and competences acquired through the mid-size robots, have been exploited in two directions. First of all, the approach to teamwork for robot soccer has been the basis for our subsequent participation in the standard platform league. The design of an autonomous mobile robot has also been transferred into the realization of autonomous rescue robots, capable of exploring indoor environments, dangerous to enter for humans, searching for victims. Further developments on the wheeled rescue robots led to new strategies for navigation and exploration [3] as well as to novel approaches to the design of the interface for the remote operator controlling multiple robots [15].
Once we started working with legged robots, we had to deal with locomotion. While this is not a major research direction in our group, we were able to establish fruitful collaborations [19, 16], to apply learning techniques [5] and to develop new features in a 3D realistic simulator [17] (Best Paper Award at RoboCup Symp. 2006).
Given our background in knowledge representation and reasoning, our long term goal is to use symbolic representations and, specifically, devise plans for robot actions. After few years focussed on the development of basic skills, we were able to support the development of our systems with an explicit representation of actions and plans. To this end we developed a formalism, called PNP (Petri Net Plans) [18], that allows for several advanced features, such as sensing actions, parallel execution, interrupts and communication among agents. Using this formalism, we provided an explicit model of the pass [13], and showed how plans can be refined through learning [10].
Last, years of experience in the design of software for robotic systems led us to
deliver our development environment OpenRDK [
We started RoboCup Camps, to share within the community the result of winning teams, thus fostering progress in the field. We organized RoboCup Camps, for midsize (Padova 2000), for four legged robots (Paris 2001), and for Rescue Robots (Rome 2004-2007). The success of this kind of hands-on schools extended outside RoboCup.
Robot competitions are sometimes viewed as pure educational activities of limited interest for research. However, the European Community has recently recognized the role of competitions by integrating its research programs on robotics with specific initiatives, supporting the benchmarking of robotic systems through competitions. Our research group is a member of the RoCKIn5 Coordination Action, started January 2013.
While RoboCup aims at a grand challenge with no direct application to real life
problems, several offsprings of RoboCup have become success stories, such as Kiva
Systems, Aldebaran Robotics and the Quince Robot in Fukushima. Our best success
story at Sapienza is the ARGOS system [
Finally, our RoboCup activity has attracted the interest of the media and of several initiatives aiming at promoting science and technology. We have been invited in several television programs in the main national Italian channels. Moreover, we have been organizing demonstrations at museums, exhibits and social spaces bringing the research in Artificial Intelligence to the attention of the general public. In particular, we have contributed in the organization of RomeCup (since 2009), mostly focused on RoboCup Junior and of Mediterranean Open (2010-2011), with international competitions of humanoid soccer robots. 5
In conclusion, we certainly did not expect all the above when we started more than fifteen years ago: RoboCup has become a well-recognized and well-established approach to research and education in Artificial Intelligence and Robotics and it has been a very successful driver for the research and academic development of our group.
Obviously, nothing comes without problems, and for those readers that might now be considering undertaking a similar project, here are potential difficulties they may have to face.
The first issue is financing: it is not easy to acquire the money needed to support the project. In fact, funding agencies (with few exceptions among which the grant we 5 http://rockinrobotchallenge.eu/ obtained by Italian National Research Council), do not provide schemes to support projects that directly target competitions, unless they are sponsoring the competitions themselves (as in the case of the ongoing DARPA Challenge, or, more recently, the European Community). Consequently, we had to collect the budget to buy the robots from our university and from sponsorships, as detailed in the acknowledgements. However, any residual money from other projects has been absorbed by our RoboCup activities.
A second key issue is the cost in terms of human resources: besides hunting for funding, managing teams of students, driving them towards successful implementations, while keeping a focus on research goals are time consuming tasks. In particular, teamwork has been a real challenge and sometimes a source of difficult relationship among the team mates; the motivations that lead to enter a competition are often strong, and can give rise to stressful situations.
Another challenge is the maintenance of both hardware and software. While this is a well-known issue for projects that target robotic prototypes, robots that play soccer break more often than ordinary robots. Moreover, the software running on the platforms is difficult to maintain, not only because of the frequent releases of components that are needed for the competition, but also because the software is developed by students that leave after a big final rush of implementation, that is usually not released in a form that supports re-use by others.
It is sometimes argued that it is difficult to keep the right balance between engineering and research, when designing and implementing systems for a competition. This is the subject of an ongoing debate in the research community: our contribution to it can be easily inferred from the results presented in this paper. Finding the right balance is a challenge, but there is a significant pay-off both in terms of research achievements and in terms of the contribution to the student’s skills and capabilities. Consequently, we keep going on.
Acknowledgements We warmly acknowledge Sapienza University, in particular our Department and our Faculty, for continuous support to student participation in the competitions. In addition, our RoboCup activities have been supported by a number of other institutions that we gratefully acknowledge: Consorzio Padova Ricerche, Italian National Research Council, Netikos, AI*IA, Epistematica, Fondazione Antonio Ruberti, Space Software Italia, Zucchetti and Algoritmica. 3. Calisi, D., Farinelli, A., Iocchi, L., Nardi, D.: Multi-objective exploration and search for autonomous rescue robots. Journal of Field Robotics, Special Issue on Quantitative Performance Evaluation of Robotic and Intelligent Systems 24, 763–777 (August - September 2007) 4. Castelpietra, C., Iocchi, L., Nardi, D., Piaggio, M., Scalzo, A., Sgorbissa, A.: Communication and coordination among heterogeneous mid-size players: ART99. In: Proceedings of Fourth International Workshop on RoboCup. pp. 149–158 (2000) 5. Cherubini, A., Giannone, F., Iocchi, L., Nardi, D., Palamara, P.F.: Policy gradient learning for quadruped soccer robots. Robotics and Autonomous Systems 58(7), 872–878 (2010), iSSN: 0921-8890 6. Iocchi, L.: Robust color segmentation through adaptive color distribution transformation. In:
RoboCup 2006: Robot Soccer World Cup X. pp. 287–295. LNAI 4434, Springer (2006) 7. Iocchi, L., Nardi, D.: Hough localization for mobile robots in polygonal environments.
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