The smart marketers at Boston Dynamics produced two major rounds of robotics news last week. The bigger of the two was, of course, the electric Atlas announcement. As I write this, the sub-40 second video is steadily approaching five million views. A day earlier, the company pulled the strings of the community when it announced that the original hydraulic Atlas was out to pasture, a decade after its introduction.
The accompanying video was a celebration of the journey of the older Atlas from the DARPA research program in an impressively agile biped ‘bot. In a minute, however, the tone changes. After all, “Farewell to Atlas” is as much a celebration as it is a reel. It’s a welcome reminder that for every time the robot sticks the landing on video, there are dozens of slips, falls and landings.
Image Credits: Boston Dynamics
I have long advocated this kind of transparency. It’s something I’d like to see more of from the robotics world. Simply showing off the highlight reel does a disservice to the effort that went into getting these shots. In many cases, we’re talking about years of trial and error spent making the robots look good on camera. When you only share the positive results, you create unrealistic expectations. Bipedal robots fall. In this respect, at least, they are just like us. As agility put it recently, “Everyone falls sometimes, it’s how we get back up that defines us.” I would take it a step further by adding that learning how to fall well is just as important.
The company’s newly appointed CTO, Pras Velagapudi, told me recently that seeing robots fall to work at this stage is actually a good thing. “When a robot is actually out in the world doing real things, unexpected things will happen,” he notes. “You’ll see some crashes, but that’s part of learning to run for a long time in real-world environments. It’s to be expected and it’s a sign that you don’t stage things.”
A quick scan of the Harvard rules for a fall without injury it reflects what we intuitively understand about the fall as humans:
- Protect your head
- Use your weight to direct your fall
- bend your knees
- Avoid taking other people with you
As for the robots, that IEEE Spectrum piece from last year is a great place to start.
“We’re not afraid of falling — we don’t treat robots like they break all the time,” Boston Dynamics CTO Aaron Saunders told the publication last year. “Our robot falls a lot and one of the things we decided a long time ago [is] that we needed to make robots that can fall without breaking. If you can go through this cycle of pushing your bot to failure, studying the failure, and fixing it, you can make progress where it doesn’t fall. But if you build a machine or a control system or a culture around never falling, then you’ll never learn what you need to learn to make your robot not fall. We celebrate falls, even falls that break the robot.”
Image Credits: Boston Dynamics
The topic of falling also came up when I spoke with Boston Dynamics CEO Robert Playter ahead of the launch of the electric Atlas. Specifically, the short video begins with the robot in a prone position. The way the robot’s legs arc around is quite original, allowing the system to stand up from a completely flat position. At first glance, it’s almost as if the company is showing off, using the flashy movement simply as a method to showcase its ultra-sturdy custom actuators.
“There will be very practical uses for this,” Playter told me. “The robots will fall. You better be able to get up from a prone position.” He adds that the ability to stand up from a prone position can also be useful for charging purposes.
Much of Boston Dynamics’ knowledge of the drop came from Spot. While there is generally more stability in the quadrupedal form factor (as evidenced by decades of trying and failing to knock robots on video), there are simply far more Spot robots working in real-world conditions.
Image Credits: Agility Robotics
“Spot walks about 70,000 kilometers a year on factory floors, doing about 100,000 inspections a month,” adds Playter. “They fall eventually. You have to be able to get back up. Hopefully you’ll reduce your drop rate — we have. I think we drop once every 100-200 km. The drop rate has become really small, but it’s happening.”
Playter adds that the company has a long history of being “tough” with its robots. “They fall and they have to be able to survive. The fingers cannot fall.”
Watching the Atlas outtakes above, it’s hard not to project some human empathy into the ‘bot. He actually appears to fall like a human, pulling his limbs as close to his body as possible to protect them from further injury.
When Agility added weapons to Digit in 2019, it discussed the role they play in falling. “For us, hands are both a tool for moving through the world – think getting up after a fall, swinging your arms for balance or pushing a door open – while also being useful for manipulating or carrying objects,” he said. co-founder Jonathan. Hurst noted that moment.
I spoke a bit at Agility about the topic at Modex earlier this year. The video of a Digit robot falling on a conference floor a year ago made the rounds on social media. “With a 99% success rate in about 20 hours of live demos, Digit still made a few drops on the ProMat,” Agility noted at the time. “We don’t have proof, but we believe our sales team orchestrated it so they could talk about Digits’ fast-changing edges and durability.”
As with the Atlas video, the company told me that something similar to the fetal position is useful when it comes to protecting the robot’s legs and arms.
The company uses reinforcement learning to help fallen robots right themselves. Agility blocked Digit’s obstacle avoidance to force the video above to fall. In the video, the robot uses its arms to cushion the fall as much as possible. He then uses his augmentative knowledge to return to a familiar position from which he can stand again with a robotic pushup.
One of the main selling points of humanoid robots is their ability to slip into existing workflows — these factories and warehouses are known as “brownfields,” meaning they weren’t built specifically for automation. In many existing factory automation cases, errors mean that the system effectively shuts down until a human intervenes.
“Rescuing a humanoid robot will not be trivial,” says Playter, noting that these systems are heavy and can be difficult to fix by hand. “How are you going to do that if it can’t come off?”
If these systems are really going to ensure uninterrupted automation, they will have to fall well and get back up.
“Every time Digit drops, we learn something new,” adds Velagapudi. “When it comes to bipedal robotics, the fall is a great teacher.”
