We emerged victorious in the Humanoid League Kid Size at the RoboCup German Open 2025. The competition, held in Nuremberg, saw us face off against the WF Wolves in a series of matches, culminating in a decisive 6-0 win in the final.

Competition Overview

We started the competition with significant hardware challenges, having only 1-2 operational robots. However, through diligent repairs and maintenance during the event, we managed to get four robots up and running by the end, including Amy, who had been out of commission since a collision at the last RoboCup World Cup in Eindhoven.

Throughout the competition, we played multiple games against the WF Wolves. Although only the final game counted towards the standings, we won all our matches, consistently leading by at least three goals. We conceded only one goal during a penalty situation where we were playing with a single robot due to maintenance issues with the others.

Software and Hardware Developments

We focused primarily on hardware repairs and maintenance during the competition. However, we also utilized a new path planning algorithm and an actual throw-in mechanism for the first time in a match. Both of these features were developed by students in the Bit-Bots Project 2024-25. Although there were no in-game throw-in situations, we tested the new features and were satisfied with the overall software performance.

In an unexpected turn, we had the opportunity to test our software on a commercially available adult-size robot from Booster Robotics, the Booster T1. This robot, borrowed from a Chinese team in the adult-size league, was significantly faster and more robust than our own robots. We adapted our software to run on the Booster T1, excluding the motion control, and participated in a test game where the Booster T1 was the only autonomous robot, playing against remote-controlled Booster T1 opponents. Our software performed well, maintaining localization and effectively blocking the ball.

During the setup of our software stack on the Booster T1, we encountered two issues. First, the robot thought it barely moved, but in reality, it was moving a lot. Upon investigating the localization data, we found a “Dropping motion due to robot moving an unreasonable amount” error. The robot was so fast that the localization system deemed its movements erroneous, even though they were accurate. Additionally, our walk speed was initially capped at 1 m/s because the slider in our parameter GUI did not allow for higher speeds. Despite these challenges, our robot performed arguably better than the humans remotely controlling the other robots, which also experienced notable control delays.

The Booster T1 robots also won the adult-size league, playing against the Sweaty team. The Standard Platform League (SPL) teams showed considerable interest in the Booster robots, as the future of the NAO robots remains uncertain.

Travel and Accommodation

We traveled to Nuremberg by train, carrying all our robots and tools. We stayed in an Airbnb conveniently located near the U-Bahn, making travel to and from the competition venue easy.

German Robotics Conference (GRC)

The RoboCup German Open 2025 also hosted the first German Robotics Conference (GRC), where one of our team members presented a paper. The conference attendees had the opportunity to visit the German Open, adding an academic dimension to the event.

Conclusion

Overall, the RoboCup German Open 2025 was an incredible experience for us. We had a lot of fun and gained valuable insights, especially from working with the Booster T1. It was exciting to see our software run on another platform with very few changes, and we learned a lot from the process. We’re already looking forward to the next competitions and can’t wait to apply what we’ve learned.

From July 15th to 21st, the RoboCup 2024 took place in Eindhoven. To allow enough preparation time on-site, we set off as early as June 12th. This year, we again decided to rent a car for the trip, which accompanied us in Eindhoven and also brought us back home safely. The car gave us plenty of space for everything we needed, and we made good use of it.

In Eindhoven, the Social Hub awaited us (our accommodation for the coming days). Here, we cooked together, checked our robots, made adjustments, and worked on small software tweaks.

On Monday, July 15th, 2024, we were able to enter the hall—or rather, the tent. It was a fairly large tent with solid flooring, no windows, and highly variable temperatures. There was an air conditioner that overcooled the space when outdoor temperatures were cooler and was not very effective during warmer weather. Inside the tent were various soccer fields (4 for our league, one for the Adult Size league next door), a robot band, a stage, the Logistics, @Home, and @Work leagues, and a merchandise shop.

We soon got to work setting up, arranging our table, putting robots on the field, and using our new flasher case for testing. The flasher case includes everything needed to power 4 robots and connect them to a computer. It is mainly used during pre-game preparations to boot up all robots and update them with the latest software. However, it also has everything necessary for testing.

In general, we worked very little on software during this World Cup because we were quite satisfied with our software status. Instead, we focused more on hardware. Early on, we decided to replace the thigh spacers, which separate the parallel leg plates, with more stable 3D-printed parts. We also removed the studs from our robot feet and used screws as studs instead because the artificial grass was very slippery.

On July 18th, 2024, things got more serious: the Drop-In Games began. In these games, each team provides just one robot, which teams up with robots from other teams to play against a similarly assembled group. Generally, there is little team strategy in these matches because the robots rarely communicate with one another. Points are awarded if our robot scores goals. Additionally, points are awarded to robots that play in the same team and are on the field when a goal is scored. At the end of the Drop-In Games, 4 teams had scored goals, and the Bit-Bots were one of them! For the first time ever, we scored a goal in a Drop-In Game. However, there was also a setback: one of our robots (Amy) suffered damage to its electronics after a fall and could not be used for the remainder of the RoboCup. We were now down to only three robots for the upcoming matches.

After the Drop-In Games, the group stage followed. Here, we were in a group with the IT Androids, the NUbots, and Ichiro. Our first match against the IT Androids ended with a 4:0 victory. We had never scored so many goals in a real match before. Against the NUbots, we had already won a friendly match earlier during the tournament, so our chances of winning this match were high. Unfortunately, we were knocked over in the center circle by the NUbots in such an unlucky way that we got disoriented. Normally, the robot uses the IMU during a fall to counteract such situations, but due to a combination of factors, this did not work, and our robot accidentally scored a goal for the opposing team. Thus, the game ended in a 1:1 draw. The last game in this round was one of the most exciting, with many duels and narrow goals. Additionally, by chance, we were given a completely blue ball, which our image recognition system was not well-configured to handle (balls usually have some white on them). As a result, our robots could not see the ball from a distance, and it remained untouched near the opponent’s goal for almost half the game. Ultimately, we lost the match 0:2. After this match, we decided to rewrite our ball-searching behavior, instructing the robot to walk to different points on the field to search for the ball if it could not find it at its initial location.

In the Round of 16, we faced the WF Wolves, the only other German team in the Humanoid Kid Size league. This team also developed the robot platform we use, so our robots look quite similar. The Wolves were also the team we had played against and beaten several times earlier in the year at the German Open in Kassel. As a result, the Wolves knew us well and tried hard to prevent us from scoring goals. This led to many falls and, consequently, significant damage to our robots. Ultimately, we won this grueling match 2:0, both goals resulting from situations where we kicked the ball close to the opponent’s goal, and the opponent accidentally scored an own goal.

In the quarterfinals, we faced Kura, a very strong team that eventually made it to the final. We prepared for the likelihood of losing but still worked on some potential improvements: a goalkeeper behavior where the robot crouches to cover more area, faster walking, and longer kicks. However, by then, our hardware was already quite worn out, and the opponent’s powerful long kicks were too effective, resulting in a 0:6 loss.

Thus, we were eliminated in the quarterfinals of the RoboCup, which, interestingly, is the same result as last year in Bordeaux. Nevertheless, we showed significant improvement: last year, proper positioning in front of the ball and some dribbling were the best our robot could achieve. We only reached the quarterfinals because we touched the ball more often during penalty shootouts. This year, we not only kicked the ball but also scored several goals and clearly won the Round of 16. We have gone from barely being present on the field to becoming a mid-tier team that can truly compete. All in all, it was a very successful RoboCup for our team.

On Friday, June 21, 2024, the ITCS, a career fair and tech conference, took place in Hamburg. The Bit-Bots were invited to set up a booth and give a presentation, and we gladly accepted.

Our booth was quickly set up, and the first robot was assembled (we always have to detach the head for transport) and started. It didn’t take long for the first curious visitors to arrive. It quickly became clear that the questions here delved much deeper into the technology. We were all the more pleased to visually demonstrate what our robot can do and to explain the software behind it.

However, we stood out a bit as exhibitors because we are not a company looking for new talents. Nevertheless, we took the opportunity to do some networking ourselves.

Around 2 PM, things got a bit exciting as it was time to prepare the robots for our presentation. At 2:30 PM, we gave our talk on why playing soccer with robots is beneficial. The quick answer: there is more than one good reason.

Here are a few more impressions:

On June 1, 2024, the Deutsches Elektronen-Synchrotron (DESY), a scientific research center in Hamburg, opened its doors to over 15,000 guests. Various research groups showcased their work, and we were there with our robots.

Our booth was located right at one of the entrances, so many visitors passed by us. As a result, we constantly had a crowd of people in front of our booth, including many wide-eyed children who were amazed. After all, you don’t see a soccer-playing robot every day.

One of our robots ran continuously throughout the day and was repeatedly used for demonstrations. We showcased walking, kicking, and cheering. For a second robot, we only ran the vision system, which was then visualized live. Children were frequently allowed to interact with the robot, positioning it in various poses and having their parents take pictures with it.

We also learned a few things about our robots that day: our demo robot ran for nearly 8 hours straight (with several battery changes, of course), which is impressive considering they usually only need to last two 10-minute halves before taking a break. Additionally, our vision system occasionally recognized children as kid-sized robots.

Overall, we had a lot of fun and thoroughly enjoyed interacting with the visitors.

From April 17 to April 20, 2024, the first German Open (GO) since 2019 took place in Kassel. Naturally, we participated with our robots again. We set off for Kassel on April 16. Most of us (Laura, Jörn, Jan-Niklas, Jan, and Lea) took the train, which was about an hour late. Timon and Flo had better luck with a rental car, including the robots and other competition equipment, and welcomed us at our accommodation with a warm meal.

Satisfied, we played a billiard match (as there was a large billiard table in the living room) and then jumped into bed. The next day, we headed to the fair early. First, we set up our workspace, unpacked the robots, and took a tour of the venue. Afterward, we diligently worked on previously discussed tasks related to both software and hardware, which were always visible in the form of labeled notes.

The first day of the GO, also known as Set-Up Day, is primarily for setting up and acclimating the robots to the new environment. Accordingly, we adjusted the “mental model” of our robots regarding the field size. There was much to do, and the day flew by quickly.

On the second day, there were three games in total. In the very first game, we achieved the goal of scoring a goal. Tragically, our robot fell in the middle of the field and, confused by the field’s symmetry, wasn’t sure which side was its own. Unfortunately, it made the wrong decision and scored an own goal. In the second half, however, we managed to score again, ending the game with a 1-1 draw.

The second game of the day was a friendly match against an SPL (Standard Platform League) team. In the SPL, all teams use the same robot model, a NAO. Despite the different rules in the two leagues, it is possible to arrange matches with a few tricks. The game ended in a 0-0 draw.

To protect some material, we played the first two games with only two robots, but for the third game, we added a third robot. This paid off, as we emerged victorious with a 2-0 win. That evening, we cooked for ourselves again and played some billiards.

On the third day, we won all our matches within our league and played another friendly match against the SPL. By now, we had become more coordinated in preparation and execution, partly due to well-defined roles during the game. We also used a new structure for pre- and post-game discussions, which helped us greatly. Earlier, we had noticed a grill in the garden of our accommodation and, with the host’s permission, invited another humanoid team (the WF Wolves) for a joint barbecue in the evening. Besides billiards, we also played brought-along card games and had good conversations.

Unfortunately, our accommodation wasn’t available for the entire time, so we had to pack up and take everything to the fair on the fourth morning. Thanks to good preparation the night before, the morning was very relaxed, and Timon delighted everyone with homemade pancakes. Well-strengthened, we tackled the next games at the fair, which we won again within our league. Between games, there was also a lot of programming to make the games run even more smoothly.

Thanks to good monitoring during the games (each team is allowed to receive data from the robots via a laptop), errors could be quickly located and sometimes even fixed within a game. We spent the evening in a hotel more centrally located in the city.

Saturday was our last and most important day. It began with a friendly match against the SPL. During halftime, the SPL teams switched, allowing us to play against the SPL league champion in the second half. This same team had won against the world champion of the Humanoid League at the World Cup in Bordeaux last summer. Therefore, we didn’t expect to win and were quite satisfied with our defeat.

Around 1:30 PM came the crucial part of the day: the final match of our league. Our robots were starting to show the wear and tear from the previous days’ games, falling more frequently when kicking but managing to get up quickly. In the first half, we managed to take the lead with a goal. In the second half, it took much longer to get the ball in front of the goal, as we fell with each kick and had to chase the ball anew. Finally, our opponent managed to score the ball we had played close to the goal line, resulting in cheers from both teams. The opposing team celebrated their first goal in the competition, and we celebrated increasing our lead. There were no further goals, and we won the final 2-0!

After the final, we had something to eat. Strengthened, we started packing. We took a short break to attend the award ceremony and collect our trophy, applauding the other winners vigorously. It didn’t take long to load everything into the car and head home. Our conclusion of the German Open: We achieved a best performance in our team’s history and are very satisfied with it.

The so named “Schnupperstudium” offers students a one-week glimpse into university life during the holidays. In addition to presenting various research fields, there are discussions with professionals and students, as well as a sample lecture and project work for the students. The projects provide a practical introduction, allowing students to continue working on them every day of the trial study week. During this week, which took place from March 25, 2024, to March 28, 2024, our team accompanied a project group and presented our robots in research demos to other groups.

At the beginning of the week, our project work involved so-called Cozmos, small robots that can be programmed via an app using a language similar to Scratch. These robots handle small cubes that can be lifted or rolled by them. The students were tasked with teaching the robots to play soccer through increasingly challenging tasks. By the beginning of the third day, a small game with three robots on each side was possible.

At the end of the week, the students worked with our large competition robots in a simulation and managed to reach the ball and score goals. Additionally, video recordings were made for the final project presentation.

Both the students and the supervising members of our team had a lot of fun throughout the week. The students reported that they wished they had more time to accomplish more in the project work. Due to Good Friday, the trial study program was shortened by one day. We were also able to help some students discover that they enjoy computer science, with one participant wanting to start studying right away. We will definitely be part of the Schnupperstudium again next year.

Until then, this month we also have the German Open (GO) coming up, where we will compete against other teams in Kassel.

From Friday, March 15th to March 22nd, 2024, we had our Integration Week. The goal of this week was to have as many members as possible in the lab during this time and to see how the individual components of a robot interact with each other. This year, we aimed to improve our walking and work on our hardware. With some snacks, we met in the lab for eight days and accomplished a lot together.

By the end of the week, we were able to walk very reliably, which allowed us to successfully move on the field and dribble the ball towards the goal. Additionally, our “Teaching Mode,” which allows positioning the robot’s motors at the push of a button, was completed. This mode was also used for a small photo session. We improved our localization and extrinsic calibration and resolved some sensor issues with our foot pressure and position sensors, opening up further possibilities for enhancing our walking. We also identified and solved a problem with the time stamps in the camera driver. As a result, we now know exactly where we’re looking, even if the robot is shaken vigorously.

Furthermore, we worked on parts of the hardware that often break. A new case for the robot’s computer was designed, improving its mounting. Moreover, we performed general maintenance on our robots, which, for example, made the walking more stable.

In the end, we all left the Integration Week very satisfied.

In November, the Bit-Bots were invited to the AI Specialist Day at the VHS Stuttgart to give a presentation and lead a workshop. So, we (Flo, Timon, Jan-Niklas, and Lea) set off very early on Wednesday, November 29, 2023, to Stuttgart. At 7 am, we all gathered at Hamburg Central Station. We would have preferred to take a later train (which we had also booked), but the railway had already canceled it in advance (as they did with our return train too).

Due to the early hour, the journey started off quite sleepy and generally quiet. This was probably because we hadn’t noticed during the reservation that it was a quiet car. As time passed, the drowsiness wore off, and the snow, surprisingly still present in Hamburg in the morning, diminished as we traveled south.

With about half an hour of delay, we reached Stuttgart and found ourselves amidst an attraction: Stuttgart 21. Although the new train station is not yet completed, on the approximately ten-minute journey out of the construction site, we were informed about the progress of the project. We had discussed beforehand to first go to the VHS Stuttgart, where the lecture would take place, and then check into the hotel we had booked for the evening.

At the venue, we were warmly greeted and led to our workshop room. Upon arrival, robots were unpacked, prepared for action, and the later presentation was practiced one last time. It didn’t take long before the first interested visitors found our room, which was well-attended at the beginning of the workshop.

In the workshop, we explained how we solve certain tasks, passed around parts of our robot for attendees to touch, and also demonstrated our robot in action. For this, we set up a piece of grass and placed our robots on it. Simultaneously, we showed on a screen what the robot was currently seeing, how it recognized balls and lines, and what it thought about itself. Subsequently, we demonstrated walking and standing-up motions.

The latter was particularly well-received, which is why we started our presentation in the large auditorium with a live demonstration. Afterward, we explained what the RoboCup is and how we use artificial intelligence in our software. The presentation can also be found on YouTube at the following link: https://www.youtube.com/watch?v=8aAUJXZS0xE

After the presentation, we exchanged a few words with our contact person, Monika Kurz. The official part was now over, and we set out in search of something to eat, finding a nice restaurant based on recommendations. Well-nourished, we were ready to head to the hotel, which was not too far away. Upon reaching the room, it was already quite late, so we all went to sleep relatively soon.

The next day, starting with a delicious breakfast, there was some time to explore Stuttgart a bit before heading back in the early afternoon. We strolled through Christmas markets in the city center, discovered a paternoster in the town hall, and walked to a small lake where there were many ducks. Finally, we bid farewell to Monika, who was delighted that our presentation and workshop went so well.

The return journey was relaxed but also productive, making the one-hour delay not as noticeable.

In the quarterfinals on Saturday, we played against the CIT-Brains team from Japan and unfortunately lost. Considering that CIT-Brains were the world champions last year, we had expected this outcome and were not too disappointed. Nevertheless, we managed to prevent a few goals. With that, we were eliminated from the competition, but it was our best result since the inception of the Bit-Bots (excluding the virtual competition during Covid-19). However, that wasn’t the last game for our robots at this RoboCup. The hosts and world champions Rhoban invited us to a friendly match at short notice, which was accompanied and filmed by Arte. We agreed and tried to get everything ready for the game as quickly as possible. During the match, our robots were able to showcase their current abilities, although there were some last-minute issues. The game was then called off after the first half, as Arte had limited time, and both teams wanted to conserve their materials. Now our robots could truly rest and recover from the games.

We still wanted to witness exciting games, so the idea arose to arrange a friendly match between the Humanoid League and the Standard Platform League (SPL). In the SPL, all teams play with the same robot model, a “Nao”. This brings some different rules and a slightly different playing field (for example, they play on relatively short grass with a standardized ball, while we can play on long artificial turf with a variety of balls). However, due to their humanoid appearance and compatible size, it was still possible to have the current world champions of both leagues (Rhoban and B-Human) play against each other. We watched with anticipation as the Naos (B-Human) won on the field of the Humanoid League.

For the remaining time of the RoboCup, we engaged with other teams, leading to an exciting experiment: we equipped our robots with the legs of the NUBots and were actually able to make them walk.

With that, the week came to an end, and so did our time in the exhibition hall. Everything was packed up and taken to our accommodation. The next day, we moved to another part of Bordeaux: the university. Here, the symposium, a scientific conference associated with the RoboCup, took place. In addition to attending different talks, we read posters and also presented one ourselves. In the afternoon, we were invited to visit Rhoban’s lab and saw some intriguing robots. With the symposium, the RoboCup concluded, and the following days were used to explore Bordeaux a bit more and head to the sea.

The RoboCup started for us with successful preparation days on Tuesday and Wednesday. Already in the first hour after entering the event hall, our first robot stood on the field and successfully took its first steps. Since a lot of effort of the AG, especially by our PhD student Marc, went into improving the walking and making it more robust last year, we had to make almost no adjustments to cross the field at top speed of 25cm/s. At the same time, preparations continued in the rest of the software. We configured and stabilized the stand-up, which usually does not work well in new environments because it has to be adapted to the robots and the grass in the field. We also developed a new component for our behavior: Since we currently can’t shoot the ball reliably, we decided to just dribble instead. Of course, this had to be practiced diligently. We also tested our localization. Localization is the part of the robot software that uses the lines recognized by our image recognition system to determine where it is on the playing field. Since that didn’t work reliably yet, we initially decided not to use the localization and just dribble the ball towards the goal.
On Thursday, the games started at nine in the morning. As usual, RoboCup starts with the so-called drop-in games. In these games, five robots compete against five robots, the special feature being that all the robots come from different teams. So the goal is for the robots to try to cooperate with other robots while playing. However, this generally doesn’t work very well and led to a lot of chaos on Thursday.
Things were a bit more structured in the afternoon during the first games of the group phase. This RoboCup has the peculiarity that there are not only one, but two group phases, with the results of the first group phase determining the distribution of groups for the second phase. In our first games, we already had all four robots ready to go and could see them running on the field at the same time. This in itself is a peculiarity in RoboCup, where the robots, which frequently fall and lose parts, need constant repair. Even though we didn’t manage to score a goal yet, we were able to defend our own goal a few times and keep the opponents from scoring. In the evening we played a short friendly match against the multiple world champion and this year’s RoboCup organizer “Rhoban” from Bordeaux. The game was also filmed by the TV station Arte and used for TV footage from RoboCup.
On Friday, after the end of the first group phase, there was a deciding match between us and the other German RoboCup team from Wolfenbüttel. The match was very nerve-wracking, as our two teams have been working together for a long time and know each other well, and of course neither team wanted to lose to the other. The game was finally decided in a penalty shootout, where we won with a final score of 5-3.
However, we and the robots were not allowed much rest, because already twenty minutes later the next game against the Chinese team TH-MOS was scheduled. Directly after that there was another match against the NUBots from Newcastle, Australia, which ended our second group stage. Both games went 0-0 and we eagerly watched the match between our two opponents to see if we would advance to the quarterfinals. The NUBots then lost the game, which means that we and TH-MOS still get to play on. Our next game will then be on Saturday in the quarterfinals against the CIT Brains. The Japanese team is the reigning world champion – so we don’t expect to win against them. Of course, that won’t stop us from doing our best and making more improvements in our software.
Apart from the games, RoboCup also consists of other aspects, especially the exchange with other teams. We like to take the opportunity to have the teams from all over the world in close proximity and exchange ideas about problems and their solutions, look at each other’s robots and fantasize about improvements to ours or analyze the other teams’ games together from the sidelines. The whole thing was even supported on Thursday evening by provided buffet, cheese, wine and French quark balls. We are looking forward to more opportunities to exchange ideas with other teams in the coming days and also at the Symposium, the scientific conference on RoboCup, which will take place on Monday.