Stumbling and Overheating, Most Humanoid Robots Fail to Finish Half Marathon in Beijing

On Saturday, about 12,000 human athletes ran in a half marathon race in Beijing, but most of the attention was on a group of other, unconventional participants: 21 humanoid robots. The event’s organizers, which included several branches of Beijing’s municipal government, claim it’s the first time humans and bipedal robots have run in the same race, though they jogged on separate tracks. Six of the robots successfully finished the course, but they were unable to keep up with the speed of the humans.

The fastest robot, Tiangong Ultra, developed by Chinese robotics company UBTech in collaboration with the Beijing Humanoid Robot Innovation Center, finished the race in two hours and 40 minutes after assistants changed its batteries three times and it fell down once.

The slowest time allowed for human runners in the race was 3 hours and 10 minutes, and Tiangong Ultra was the only robot that barely qualified for a human participation award. Most of the humanoid participants didn’t stay in the game for long and disappeared from the live broadcast soon after they took off from the starting line.

Alan Fern, a robotics professor at Oregon State University, tells WIRED that researchers who build these robots typically focus on trying to get them to complete tasks and respond coherently in a diverse range of different environments, rather than run as fast as possible. Fern adds that the AI technology used in humanoids hasn't progressed very much since 2021, when his team sent a bipedal robot to run a 5k race.

What the race does demonstrate, he says, is how robust humanoid hardware has become. “Until five years ago or so, we didn't really know how to get robots to walk reliably. And now we do, and this will be a good demonstration of that,” he told WIRED on Thursday before the race took place. His team’s robot fell twice during the 2021 5k run, once due to operator error and another due to overheating. “The impressive thing about going from a 5k to a half marathon is really a hardware robustness problem. And you know, I'll be surprised if one of these companies makes it through without replacing the robot,” he says.

Fern’s predictions were totally right. On Saturday, almost every robot fell down and faced overheating problems, prompting their operators to switch them out for new replacements. While the event did generate a lot of interest and pride among Chinese people—many human runners stopped to take selfies with Tiangong Ultra when they saw it—it also showed the reality and limitations of China’s humanoid robot industry.

Impressive looking humanoid robots developed by several Chinese companies have made international headlines this year. One robot firm called Unitree, for example, went viral in January after it sent an army of robots to perform synchronized dances during China’s Spring Festival gala on state TV. Unitree didn’t officially participate in the race, but two of its robots were still running the half marathon while being operated by other institutions. (One of its robots fell on the ground before reaching the starting line and struggled to stand up quickly.)

While capabilities like dancing can be fun and eyecatching, they don’t actually show how useful humanoid robots are in real-world situations, says Fern. Even being able to run a half marathon isn’t a very useful benchmark for their skills—it’s not like there’s market demand for robots that can compete with human runners. The benchmarks that Fern says matter to him are how well they can handle diverse real-world tasks without step-by-step human instructions. “But I would expect to see China shifting this year to focusing more on doing useful things, because people are going to be bored of dancing and karate,” Fern says.

The robots who participated in the race came in a variety of forms. The shortest one was only 2 feet and 5 inches tall. Sporting a blue and white tracksuit and waving to onlookers every few seconds, it was probably the crowd favorite. The tallest, at five feet nine inches, was the winner Tiangong Ultra.

What all of the robots have in common is that they are bipedal instead of running on wheels, a requirement to participate in the race. As long as the robots met that requirement, they were free to get creative, and the companies behind them adopted a wide range of strategies to try to get an advantage over their competitors. Some were wearing kid-sized sneakers (though screwed to their pedals to avoid falling off). Others were equipped with knee pads to protect their delicate parts from damage when they fell. Most of the robots had their fingers removed and some were even missing heads—you don't need such parts for running, after all, and taking them off reduces a robot’s weight and the amount of burden placed on their motors.

Tiangong Ultra and another model, the N2 robot made by Chinese company Noetix Robotics, which won second place in the race, stood out for their consistent, albeit slow pace. The performance of the other humanoids was mostly disastrous. One robot called Huanhuan, which has a human-like head, only moved at the speed of a snail for a few minutes while its head shook uncontrollably—as if it could fall off any time.

Another robot named Shennong looks like a real Frankenstein’s monster, with the head that resembles Gundam and four drone propellers that face backwards. It sits on a foundation with eight wheels, and it’s not clear how that alone wasn’t disqualifying. But that wasn’t even Shennong’s biggest problem, as the robot immediately twirled in two circles after taking off from the starting line, hit the wall, and dragged down its human operators with it. It was painful to watch.

Duct tape proved to be the most effective problem-solving tool. Not only did the accompanying humans make makeshift robot shoes with duct tape, they also used it to adhere the head of a robot back onto its body after it repeatedly fell off during the run, making for some very jarring scenes.

Every robot had human operators, often two or three running beside them. Some held control panels that allowed them to give the robot instructions, including how fast to go, while other operators led the way for their robots and tried to clear potential obstacles on the ground. Quite a few of the humanoids were being held on what looked like, well, pet leashes. “You wanna think of these robots more like running a remote control car through the race. But the robots don't have wheels,” says Fern.

In fact, by the end of the race, many people who tuned into the livestream started to comment on how exhausted the robots’ human operators looked. They were guiding the robots where to go, furiously changing their batteries, and endlessly spraying liquid on them to cool down their motors, all while running (or walking, to be honest) 13.1 miles on their own.

Besides running and tripping, some of the robots also performed dances and backflips. Seven robot dogs and one humanoid also performed more dances on a nearby stage. At the end, yet another robot brought the trophies onto the award stage and presented them to their four fellow robots who completed the run.

The limitations of the robots, however, could make for some memorable scenes. Xuanfeng Xiaozi, a robot developed by the Chinese company Noetix, started off strong but broke down more and more frequently towards the end of the race. At one point, it fully plunged to the ground, face down, and its head became dislodged from its body. A team of human operators quickly swooped in with duct tape to fix things and put Xuanfeng Xiaozi back on its way.

When it was finally almost done with the race, Xuanfeng Xiaozi had a cooling pad attached to its front and its right foot was out of step with its left, and yet, it still managed to wobble to the finish line, where the runner-up robot, made by the same company, had been waiting for it for ten minutes. The half marathon certainly showed off the design flaws of these robots far more than their capabilities. But still, at that moment, I was really happy to see Xuanfeng Xiaozi finish the race.