The VP of Engineering at Boston Dynamics visits a small town in Germany to explain how 3D printing and fluid power contributed to dramatic weight savings and power efficiency in the latest generation of their Atlas humanoid robot.
In the city of Aachen, Germany this past week, more than 650 “fluid power” manufacturers, specialists and academics had gathered to talk about the latest innovations in hydraulics and pneumatics technology.
The closing keynote was by Aaron Saunders, VP of Engineering at Boston Dynamics, who spoke about the role that fluid power and additive manufacturing have played in the development of their Atlas humanoid robot.
To the uninitiated, Boston Dynamics is robotics company based in Massachusetts, made famous by their YouTube channel featuring bipedal and animal-like robots that jump, run, and even do back-flips. So famous, in fact, that Google decided to buy them.
The subject of Saunder’s talk was about building Atlas, and the continuous process of redesign and refinement. The story began in 2009, where Boston Dynamics literally sawed one of their quadrupeds in half to make a biped robot.
“In 2012, there was a big competition started in the U.S. to use mobile robots to use in disaster response scenarios, and the government asked them to build 10 robots to give to universities to learn how to access these difficult trends,” Saunders said.
Boston Dynamics used off-the-shelf components to put this hydraulic robot together, which was 2 meters tall, self-contained, and weighed nearly 200kg.
“In 2015, we got the opportunity — when we were acquired by Google — to really look inside and focus on things that we thought were important. We used the opportunity to redesign this humanoid robot from the ground up, and we ended up with a robot that’s very similar. It has all the same strength and range of mobility.”
This newer Atlas model is about 1.5 meters tall and weighs 80 kg. It has an increased strength density to near human levels, is completely power autonomous (running between 30-60 minutes, depending on acitivity) and has 28 degrees of freedom. 3D printing technology has played a key role in this version of Atlas.
“When we started the program, I’d read a lot of glossy magazine ads about how 3D printing was here. You could use it, you could print and go. That’s not quite true, but it is a very promising technology and it’s evolving rapidly,” Saunders said.
The robot’s leg makeup was, Saunders enthuses, “probably our biggest undertaking. We learned a lot of lessons … we integrated the structure, the manifold and the fluid routing and actuator cylinders all into one structure.”
“We were able to reduce limb inertia significantly, which is a big deal for a walking robot — most of the power in the system goes to swinging the legs through the air and accelerating and stopping them. You do very little work on the world when you’re a biped and you’re walking — you’re actually very efficient. But you need a lot of power to swing legs, especially when they’re heavy, so this was a big deal,” he said.
“We have a saying in our company called the bleeding edge. A lot of people talk about leading edge technology and the leading edge for us is when you’re going too far. The leg was very challenging because there was a lot of stuff integrated into it. Just finding a company to hone an actuator cylinder in a 3D printed material that had never been qualified before is a massive challenge. The number of close processing steps you have to go through as opposed to traditional machining really started to erode some of the benefits. In the end, we still saw that benefit in the inertia, but the effort to get this part out was quite significant,” Saunders said.
Similarly, the Hydraulic Power Unit (HPU) uses 3D printing to achieve greater efficiency.
“It’s approaching a kilovolt per kg of density, it’s pretty scalable,” he said. “It sits in the center of the robot. It has everything it needs to collect electrical power and put hydraulic power out … All the homeostasis, sensing, filtration, dump valves, everything we need for the power plant is integrated into a printed part. This lets us wrap everything really tightly around the reservoir—and uses empty space that’s otherwise not used.”
Atlas’ manifold has 18 valves, which service the upper body of the robot.
“This is where we are getting close to a sweet spot in printing,” Saunders said, “so we can make very organic structures and minimize pressure drops—get rid of a lot of excess components. It’s kind of exciting, the things that can be done in printing manifolds.”
But, he emphasized, he wants to see more component manufacturers come forward and expand their offerings for uses like robotics.
“For us, I think one of the big things is the availability of small components. I would love to be able to come to a group like this and find more components on the human scale for mobile applications,” Saunders said.
“Developing that valve was really fun, but we’re a robotics company — and we’d like to do more robotics and less component development. So, finding places that work with people to develop these small components on the timescales that are relevant is an area that it’d be great to see more of.”
Source: Design World
License: The text of "Boston Dynamics VP of Engineering Talks About 3D printing" by All3DP is licensed under a Creative Commons Attribution 4.0 International License.
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