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April 21, 2025
Last weekend, a special kind of half marathon took place in Beijing. In addition to around 12,000 human runners, 21 humanoid robots also participated in the competition. The organizers, including several Beijing municipal authorities, spoke of a world-first race of this kind, although humans and robots ran on separate courses.
Of the 21 participating robots, only six reached the finish line. The fastest robot, Tiangong Ultra, developed by the Chinese robotics company UBTech in collaboration with the Beijing Humanoid Robot Innovation Center, needed two hours and 40 minutes to complete the course. The team had to change the batteries three times, and the robot fell once.
The maximum running time for human participants was three hours and ten minutes. Tiangong Ultra was thus the only robot that would have qualified for an award. Most robots dropped out early and quickly disappeared from the live broadcast of the race.
Experts emphasize that the development of humanoid robots primarily aims at mastering diverse tasks and reacting to different environments, not at maximum speed. Alan Fern, a robotics professor at Oregon State University, explains that the AI technology used in humanoid robots hasn't made significant advancements since 2021, when his team entered a bipedal robot in a 5-km run.
The Beijing half marathon, however, demonstrates the increasing robustness of the hardware. Just a few years ago, it was a challenge to get robots to walk reliably. The competition highlighted the progress in this area. Fern's team experienced their robot falling twice during the 2021 run – once due to an operating error and once due to overheating. The leap from five kilometers to a half marathon is primarily a matter of hardware robustness.
Fern's predictions proved true: Almost every robot fell during the race and struggled with overheating problems, necessitating the use of replacement robots. The event generated significant interest and pride in China – many runners took selfies with Tiangong Ultra – but also showcased the limitations of Chinese humanoid robotics.
Chinese companies have made headlines this year with impressive humanoid robots. The company Unitree, for example, achieved viral fame in January with a synchronized robot dance during the Chinese New Year gala on state television. Unitree did not officially participate in the race, but two of their robots ran under the direction of other institutions. (One of the robots fell even before the start and struggled to get back up.)
Such demonstrations, while entertaining, do not show the actual usefulness of humanoid robots in everyday life, according to Fern. Even the ability to run a half marathon is not a meaningful benchmark. More important is how well robots can handle diverse tasks without detailed human instructions.
The participating robots featured different designs. The smallest was only about 75 cm tall, wore a blue and white tracksuit, and waved to the spectators. The largest, the winner Tiangong Ultra, measured 1.75 meters. Common to all robots was the bipedal gait, a prerequisite for participation in the race. Beyond that, there was a wide range of strategies and modifications. Some wore children's shoes (screwed to their feet), others had knee pads. Many robots lacked fingers, and some even lacked heads, to reduce weight and relieve the motors.
Tiangong Ultra and the N2 robot from Noetix Robotics, which took second place, were characterized by a constant, albeit slow, pace. The performance of the other robots was less successful. A robot named Huanhuan moved at a snail's pace for only a few minutes while its head wobbled uncontrollably. Another robot, Shennong, reminiscent of Frankenstein's monster, with a Gundam-like head and four rear-facing drone propellers, stood on an eight-wheeled base and spun in circles after the start, crashing into a wall and dragging its human operators with it.
Each robot was accompanied by two to three human operators. Some controlled the robots via control panels, others led them on leashes and cleared obstacles out of the way. Towards the end of the race, many operators showed signs of exhaustion. They had to guide the robots, change batteries, cool the motors, and cover the half marathon distance themselves.
In addition to running and falling, some robots also performed dances and backflips. Seven robot dogs and a humanoid robot danced on a stage. At the end, another robot presented the trophies to the four robots that had successfully completed the race.
The robots' limitations led to some memorable scenes. Xuanfeng Xiaozi, a robot from Noetix, started strong but had increasing problems towards the end of the race. It fell face down, and its head detached from its body. The operators rushed in with adhesive tape to repair the robot. Finally, Xuanfeng Xiaozi, with cooling pads and an uneven gait, reached the finish line, where the runner-up, also from Noetix, had already been waiting for ten minutes.
