Human evolution is basically a time-lapse of us learning to walk better. First, we started on all fours, then we figured out how to balance on two legs, and eventually, we strutted our way to dominance. The same thing is happening with humanoid robots right now—except while some can move as well as we can, others are a bit further down the evolutionary tree.
Walking Is a Big Deal for Humanoid Robots
If humanoid robots are to be as useful as we imagine, they need to be able to interact with a world built for people. That means going where we go and doing what we do. But we don’t always walk on smooth, even ground. We climb stairs, step over curbs, and trek through rocky terrain. Wheels struggle with all of that.
Legs, on the other hand, are tried and true. They allow robots to go more places, and do more things. And if we want robots to take on dangerous jobs like firefighting or space exploration, they’ll need to handle treacherous terrain without getting stuck at the first bump in the road.
You Don’t Think About It, but Walking Is Really Hard
When you roll out of bed for your morning coffee, you probably don’t give it a second thought—but your body is pulling off an incredibly complex set of maneuvers. Throughout your lower body, dozens of muscles fire at just the right time to move one leg in front of the other, while maintaining your balance all the while your brain makes tiny corrections so you don’t tip over when you encounter obstacles.
It’s so effortless for us that we hardly notice, but when you break it down into individual steps, you get an idea of just how hard walking is.
Any robot that walks upright also has to do more or less the same thing, except instead of muscles, it relies on actuators to make movement and an onboard computer to make corrective adjustments on the fly.
The Best Walkers Today
Different humanoid robot companies have taken up the challenge of creating the perfect bipedal robot. Some share similar ideas, while others take wildly different approaches. But who’s leading the pack? We’re ranking the top contenders to see who’s mastered the art of walking.
Each robot will be graded between 1 and 5 in four key areas:
- Gait: How smoothly does it walk? Are its movements fluid and natural, or does it hobble?
- Speed: How fast can it walk? Can it run, or is it confined to a slow shuffle?
- Recovery: How well does it handle unexpected obstacles? Can it maintain its balance when it’s shoved in the back?
- Flexibility: What’s its range of motion? Can it jump, or even pull off a backflip?
So let’s get those scorecards ready, the athletes are ready to compete.
5
Tesla Optimus
I was genuinely impressed when I watched Tesla’s demo for Optimus 2—at least, up until it started walking.
Scrolling through the comments section, I found a quip that summed up my thoughts about Optimus perfectly. It said, “… Looks around, moves its head and hands fluidly and naturally… and then walks away like it [redacted] its pants.” I couldn’t have said it better myself.
If you watch the video, you’ll see exactly what I mean. Optimus’ gait is stiff and awkward, with short, shuffling strides. Something about its design also makes it look slightly hunched over, giving the impression of an 80-year-old grandpa inching his way across the room. Considering all this, for gait, I had to give it a 2.
Next was speed, and Optimus didn’t earn many points here either. According to a post from Tesla’s Head of Optimus Engineering, Optimus moves at about 0.6 meters per second, and while that is an improvement from the last demo, it still isn’t very fast. We’ve also never seen Optimus run—we don’t even know if it can—so for speed, I gave it a 2.
Recovery came next, and here Optimus finally made a good showing. I based my judgment on a YouTube Short showing Optimus walking up and down a slope of packed dirt.
While its gait was particularly atrocious during the attempts, it did manage to make it up and down the hill without incident. At one point in the video, the sand beneath Optimus’ feet gave way, and it made a quick correction to keep from falling. That impressed me a lot, so I gave it a 3 in this category.
Flexibility was a tough one to judge. On the one hand, Optimus has demonstrated balancing on one leg and holding a yoga pose.
On the other hand, I’ve never seen Optimus jump, spin, or execute any complex lower-body movements. Even in its “dance” demos, it mostly moves its arms while barely engaging its legs. After some debate, I settled on a 2 for flexibility.
That brings its total score to 9 out of 20, which explains its spot in the rankings.
4
Figure Robotics
I’ve written about Figure before, so I already had a good idea of how their robots move—and honestly, I didn’t have high hopes for them in this test. But to my surprise, Figure has made solid improvements since I last checked them out. They recently released a video showcasing their advancements in natural walking, and I have to admit, it’s pretty impressive.
The Figure robot is no longer hunched over or taking shuffling steps. Instead, it stands straighter and takes larger, more natural strides. The improvement is significant enough that I’m giving them a 4 for gait.
From the same demo, it’s clear that Figure has achieved a decent walking speed. Judging by the video, it seems to move at a pace similar to a leisurely human walk. However, since we haven’t seen it run yet, I can only give it a 3 for now.
Unfortunately, there’s little information on how well Figure’s robots recover from slips or handle rough terrain. The same goes for flexibility—there’s just not enough data. Because of this, I have to give it a 1 in both categories.
That brings its total score to 9, putting it in a tie with Optimus.
3
Agility Robtics’ Digit
One of the first things you’ll notice about Digit is that its legs are very different from those of its competitors. Instead of humans’ straight limbs, Digit’s legs are curved, resembling a bird’s.
This style of legs is called digitigrade, and that’s probably where the name “Digit” comes from too. Judging Digit’s gait was a bit challenging because of its unique design, but after watching a few videos of ostriches running, I settled on a 3—not bad but could be better.
For speed, I gave Digit a 2, which was a bit of a disappointment considering its older sibling, Cassie, set a Guinness world record for the 100m run. But then again, Cassie had no torso, so maybe the extra weight is responsible for Digit’s less agile movements.
When it comes to recovery, Digit does reasonably well. It walks uphill and downhill through sand, grass, and even a little mud without much trouble.
However, most of the terrain it’s tested on is flat and smooth, and we never see it stumble and right itself before falling. Because of this, it scored a 2 in this category.
For flexibility, I scored Digit a 3 simply because its unique design allows it to fold and extend its legs, allowing it to quickly bend and stretch to reach places that other humanoid robots might not.
So, Digit’s final score is 10 points.
2
Boston Dynamics’ Atlas
Boston Dynamics recently made significant changes to how its Atlas robot looks and moves. For starters, the new Atlas uses actuators instead of hydraulics, and it also has more joints with a wider range of motion, allowing for greater flexibility and rotation in all directions.
Despite these changes, the new Atlas appears just as—if not more—capable than its predecessor. It moves with smooth, natural motions, walking just like a human and even running when needed. I gave it a 5 in both gait and speed.
We haven’t yet seen the new Atlas tackle rough terrain or withstand a shove, but since HD Atlas passed those tests effortlessly and this version is an upgrade, I’m confident enough to give it a 4 for recovery.
Then there’s flexibility—an area where Atlas truly excels. It can crouch, crawl, roll, do a cartwheel, breakdance, and even land a backflip. With that level of agility, anything less than a 5 wouldn’t do it justice.
All in all, Atlas scores a total of 19 points.
1
Unitree G1
You might be surprised that the Unitree G1 has managed to top this list, even surpassing Boston Dynamics’ Atlas, which has long been considered the gold standard of humanoid robots. But if you watch its Agile Upgrade demo, you’ll understand why I made this call.
While I have no doubt that Atlas performs well, Unitree simply put its robot through far more rigorous testing. First, we see it walking across a flat surface, then jogging along train tracks at speeds comparable to a human. It effortlessly navigates a rocky path and moves up, down, and even sideways on slopes. This demonstration alone convinced me to give it perfect scores in both gait and speed.
But G1’s capabilities don’t stop there. In other videos, we see it enduring even more extreme tests. In one, it executes a 720º spin kick and accurately hits its target while remaining upright.
In another one it takes a hard blow from behind—yet still manages to stay upright.
After seeing this, I had no choice but to give it perfect scores in both recovery and flexibility as well, earning it a flawless 20/20.
As you have no doubt seen, humanoid robots are advancing at an incredible pace, and it won’t be long now, until they are walking among us. Unitree’s G1 may have claimed the top spot for now, but with these companies constantly innovating, I wouldn’t be surprised if, in just a few months, one of them has a breakthrough that completely reshuffles the rankings.
