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Roboticists from industry and academia share their perspectives on Tesla’s new humanoid
Tesla CEO Elon Musk unveiled the Optimus humanoid robot at AI Day on 30 September. In a brief demo, the robot walked, waved, and danced on stage. While robotics experts praised the Tesla team for putting the prototype together so quickly, most were unimpressed by its design.
Last Friday, 30 September, Tesla introduced several prototypes of its new humanoid robot, Optimus. After a year of speculation based on little more than a person in a robot suit combined with some optimistic assertions made by Tesla CEO Elon Musk, many roboticists tuned in to the event live stream (or attended in person) to see what Tesla’s approach to humanoid robotics would turn out to be.
Reactions across the robotics community were diverse. Because robotics requires expertise in many different aspects of both software and hardware, getting a good sense of the present context of Tesla’s robot as well as its future potential means finding perspectives from a multitude of robotics experts, including people working in industry and academia and everywhere in between. And by scouring the Internet over the weekend, we found as many expert commenters as we could. Together, they offer the most detailed and nuanced understanding of Optimus we’re likely to get outside of Tesla itself.
These robotics experts posted their thoughts on Twitter, LinkedIn, Substack, and elsewhere, and with their permission, we’ve collected them for you below. Many of these folks wrote a lot more than we have room to include, but you can follow the link in a particular expert’s name to see their complete commentary.
Experts on Optimus Georgia Chalvatzaki — Assistant Professor, Technische Universität DarmstadtKate Darling — Research Specialist, MIT Media LabAnimesh Garg — Assistant Professor, University of TorontoRyan Gariepy — CTO, Clearpath Robotics & OTTO MotorsKeerthana Gopalakrishnan — Roboticist, Google BrainDennis Hong — Professor, UCLAChristian Hubicki — Assistant Professor, Florida State UniversityWill Jackson — Founder and CEO, Engineered ArtsGary Marcus — Author, Rebooting AIBrandon Rohrer — Machine Learning Engineer, LinkedInSiddhartha Srinivasa — Director of Robotics and AI, AmazonMikell Taylor — Principal Technical Program Manager, Amazon RoboticsCynthia Yeung — Founding Board Member, Women in RoboticsClick the link under each section to jump back up to the list of experts. Georgia Chalvatzaki Assistant Professor, Technische Universität Darmstadt Looking at the Tesla Bot as a roboticist, I am impressed by what the engineers achieved for this prototype in a year. However, the behaviors demonstrated are less impressive than that of Honda’s Asimo from 20 years ago. What excites me is the idea of cheap and accessible hardware! The electric motors with the battery support could make a very good tool for academic research. It takes way more to solve manipulation, but Academia looks forward to getting your hardware! [ BACK TO TOP ↑ ] Kate Darling Research Specialist, MIT Media Lab The sense I’m getting is that Optimus isn’t as bad as people thought, but also, nobody [in the robotics community] is very impressed or surprised by any of the tech. [ BACK TO TOP ↑ ] Animesh Garg Assistant Professor, University of Toronto The Optimus effort is, in a sense, no different from Asimo, Atlas, T-HR3, or Digit. All of them are backed by expert roboticists with years of design experience. However, the Tesla Robotics team has done a commendable job in fast iteration time for the design of the robot from the ground up, [following the path from] a good experimental study on actuator requirements, to designing new actuators, then creating the integrated system. The current locomotion stack is not using any machine learning, but rather trajectory optimization using reference controllers. This is a sensible design choice to get up and running, but would definitely need redoing for longer-term operation. The hand also seems exciting, with a metallic cable-driven system with four fingers and a thumb. In the brief demo, they showed it had a reasonably high loading capacity (holding plant-watering water cans, and lifting bars of aluminum in the factory). However, due to the cable-driven design, the system will have slower response time, harder to do learning-based control, and no backdrivability in autonomous mode. This will make general-purpose autonomous manipulation slightly challenging. Robots, in the short term, have use cases in places where they do not necessarily need to interact with humans and the implications of failure are less severe. The community needs to find a revenue-positive pathway to support this development. And this could come from behind-the-scenes use cases for robot manipulation, in warehouses, retail stores, food preparation, and manufacturing. While automation-based solutions are still being pursued, it remains to be seen how a general-purpose hardware-based solution would stack up. We would need to look to low-volume, high-variability products which require quick adaptation. Tesla would benefit a lot from collaborating with the community. Tesla already has the community taking notice, and by being more open, Elon would only empower more people to work on the problem—which is, after all, “beneficial to humanity” —which Elon claims is their driving principle. Designing the whole stack of hardware, simulation, and data infrastructure is requiring Tesla to reinvent the wheel on many fronts. Overall, the current design is a very good first step. Interest in building such systems is welcome because Tesla and Elon Musk’s involvement in the problem brings attention, talent, and resources to the problem, setting in motion a flywheel of progress. This effort should be lauded with cautious optimism by the community, for the compass points in the right direction, and Elon brings with him the heft of Tesla engineers as we trek through the AI/Robotics jungle. [ BACK TO TOP ↑ ] Ryan Gariepy CTO, Clearpath Robotics & OTTO Motors Great credit to the engineering team who pulled it off, of course, but I’m not seeing anything particularly impressive here which we can attribute specifically to Elon or Tesla. Specifically, there were lots of arguments ahead of the unveil that one or more of the “Tesla FSD stack/data/EV experience” was going to let them leapfrog all of the other companies in the space and I didn’t see any of that. There’s also lots of credit going to Elon for saying that “it’s going to cost 20K,” which reminds me of all the 3D lidar companies that have been saying “our lidar will only cost [US] $100...if you pre-order 100K+ units.” In short, I’d bet that any decent university or corporate robotics lab with a similar budget and an active PR team would be able to pull this off. [ BACK TO TOP ↑ ] Keerthana Gopalakrishnan Roboticist, Google Brain Optimus reveal: Mind blown with the velocity of the team and the very sleek hardware design elements. Yet to see autonomy. Surprised Tesla went full Boston Dynamics mode with classical control/planning when it’s been around for a while… [ BACK TO TOP ↑ ] Dennis Hong Professor, UCLA The energy and excitement at AI Day 2 was amazing. “AI Day” is actually a recruitment event, and in that sense I believe the event was a big success. I am aware of critics who say that the prototype had nothing new that they haven’t seen elsewhere, and that there are other, more impressive humanoids. There are also people who have doubts about the aggressive timeline Elon had proposed, and I do not necessarily disagree with them. That being said, I am a true believer of the future with humanoid robots and their eventual applications; that they will be used in our everyday lives “one day” and make our lives better. And for that to happen, we need to start somewhere and project Optimus is just that. What was most impressive to me was what the Optimus team was able to accomplish in such a short period of time. If you are in this field, you would agree, too. The prototype they have created will serve as an excellent beginning platform for them to learn from and to build upon. I would say this is their good first step towards something big—if Tesla truly commits to put its resources, time, and efforts into it long term. The company has great engineers, and with the newly recruited talents, I am even more excited to see what they’ll be able to accomplish next. [ BACK TO TOP ↑ ] Christian Hubicki Assistant Professor, Florida State University Am I blown away? No. Am I laughing? No. First, the team did a good job. They came a long way in about a year(?), going from zero-to-robot from the ground up. Also, doing a live demo without a tether (safety-catch rope) is braver than people know. Let’s talk walking. I told my lab today that I expected it to walk on stage, and it did, but I was a bit surprised at how they did it. It seems to use a method called zero-moment point to maintain balance. It’s been used in various forms since the 1990s. You see ZMP in the bent knees and how it shifts its weight over to its next foot before taking a step. It’s pretty safe, but not mind-blowing in 2022. Also, people don’t walk quite like this. We are more efficient—we stick our foot out, fall, catch, repeat. There’s a portion showing off the vision, manipulation, and “smarts.” It’s hard for me to glean the methods here because it’s a cut video, so I don’t have much to say. I don’t know how much is pre-canned vs. online planning. I will also let everyone in on a secret about humanoids: It’s all about reliability. How often does it fall down? You can’t tell from a cool video—or even a live demo. Musk mentioned a [US] $20K price point, which would be a big deal. The cheapest human-size humanoids I’m aware of are in the $150K range (a long way from the olden days of $1M price tags)… But I’ll believe the price when I can actually buy one. [ BACK TO TOP ↑ ] Will Jackson Founder and CEO, Engineered Arts [I was] fortunate enough to have been at the Optimus unveil in Palo Alto last night. Had a chance to check out the design and talk with many of the engineers involved. It’s generally an old-school series chain of actuators, excepting wrists and ankles, which are differential roll/pitch. Nothing novel in the kinematics. No mechanical energy storage, parallel springs, etc.—it’s not going to be efficient unless they change that. Two main classes [of actuators]: rotary and linear. Rotary is an integrated strain wave gear reduction (harmonic drive). Linear actuators are more interesting, integrated inverted roller screw drive. Playing with a drive, it’s not inherently very transparent—you certainly wouldn’t get a free swinging knee or hip joint. All the actuators look like they need and use active force loops. This looks nasty to me: It will complicate the control, reduce efficiency, and raise complexity. If they really want to get to [US] $20,000 a unit, this is not the way to go. Hands: One novel feature here is a clutch on the finger flex/extend. Playing with an actual hand, it felt like it worked quite nicely to decouple the finger from the drive; this will have advantages. The design of the hands leaves very little room for a compliant (soft) layer, and bare metal hands are a terrible idea—try picking up a glass of water with two metal spoons and you will know what I mean. No finger ab/adduction, only two DOFs in the thumb—no chance of doing anything human-level dexterous here. [Tesla has] a large team of highly capable engineers and will iterate quickly to better designs—if they can find a leader for the mechanical architecture with better ideas than they are currently showing. The elephant in the room is the application ideas, which are frankly ridiculous. I am amazed that Musk can address an audience so rapturously enamored with the idea of a humanoid and totally fail to recognize that their desire to interact with a robot is the killer application. Did he think they were applauding because finally the world will have a humanoid robot that can lift a pipe in a car factory? Summary: An extraordinarily brave live demonstration of a herculean effort that sadly lacks novelty and imagination. Hopefully we will see a course correction by the time of next year’s event. [ BACK TO TOP ↑ ] Gary Marcus Author, Rebooting AI The Optimus demo turned out to be a bit of a dud. The challenge for Tesla isn’t really so much the mere fact that Boston Dynamics robots are ahead (or that Agility Robotics is also doing similar work). With enough investment, Tesla might in principle catch up. If Musk really wants to win the robotics race, he has the resources to do so. (Though he clearly has not invested nearly enough so far.) What I didn’t see last night was vision. I mean this in two different senses. First, there was no clearly outlined vision for what Optimus would do, nor much justification for why Tesla is building the robot in this specific way. There was no decisive justification for why to use a humanoid robot (rather than, for example, just an arm), no clarity about the first big application, no clear go-to-market strategy, and no clear product differentiator. Second, there was very little vision for how Tesla would build the cognitive part of the AI they will need, beyond the basics of motor control (which Boston Dynamics already does so well), nor much recognition about why robotics is so hard in the real world. For me, the most worrisome part of last night’s presentation was not the lack of a world-beating demo, but a lack of recognition of what would even be required. [ BACK TO TOP ↑ ] Brandon Rohrer Machine Learning Engineer, LinkedIn Huge kudos to the Tesla team for putting the Optimus prototype together this quickly. Clearly a world-class engineering team at the top of their game. A lot of nights and weekends there. But it’s only about 5 percent of the way to what’s being sold. The upper body actuators have harmonic drives and the leg actuators are screw driven. Backdrivability can be added to some actuators if you also include torque sensors and close a very fast control loop around them. But it doesn’t come without adding cost and complexity to your design. Low backdrivability leaves a robot rigid to external forces. When you try to compensate for it through software control loops, you can get a telltale wobble. If you watch Optimus’s hands as it walks, you can see this wobble is in the 4-hertz range. We were also teased with the almost finished, “almost production-ready” model. It can wiggle its fingers, but the backdrivability limitations have not been addressed. These are all tractable problems, but they’re hard. Probably not 12 months out. I’m delighted to see such an ambitious robot project in the world! But it doesn’t help the field of robotics to over-promise. We already tried this in the ’80s, and it took us 30 years to recover. [ BACK TO TOP ↑ ] Siddhartha Srinivasa Director of Robotics and AI, Amazon My take on the Tesla Bot: You’re not as good as you think you are. You’re also not as bad as they think you are. [ BACK TO TOP ↑ ] Mikell Taylor Principal Technical Program Manager, Amazon Robotics There is no “doing it first” with an all-purpose humanoid robot that can 1:1 replace people. That’s simply not where the tech is now and it’s not where it’s going to be in the next 10 years, I will say with complete confidence. Those of us in the industry were watching to see if Tesla somehow knew something we didn’t know. And…nope. They did not. The tech isn’t there for anyone. And that’s why the more generous takes some of us try to make for the sake of the engineering team are “you did as well as you could and you’re figuring out the state of the art quickly.” It’s not that team’s fault. There was no way to achieve an impossible goal. Here’s the thing. What humanoid robotics needs is a realistic vision. A “here is exactly where this, a humanoid form factor, is needed instead of literally anything else” vision that acknowledges the realities of the technology. But that’s not what it was. It was “today we have this, in a year we’ll have sci-fi.” And that’s just not going to happen. Frankly, it’s disappointingly un-visionary. “Everyone else just hasn’t engineered hard enough” is not a vision. It’s ignorance. [ BACK TO TOP ↑ ] Cynthia Yeung Founding Board Member, Women in Robotics Things I liked: Sharing the spotlight with engineersCool actuators and simulatorsExpression of humility toward the end when [Musk] admits they may be “barking up the wrong tree” in terms of technical approach Things I didn’t: Musk, referring to competitors’ robots, is claiming that Optimus will be autonomous and cost < [US] $20k (BOM or retail price?). From a product perspective, <$20k capex with zero recurring fees isn’t a great revenue model when all the robotics startups are moving toward RaaS models.Battery details: Tesla claims [2.3 kWh] will be enough for a full day’s work. Agility Robotics’ Digit batteries last 3 hours for light duty. This doesn’t pass the sniff test.A lot of talk about joints and actuators. I think Musk seems to be enamored of the Boston Dynamics approach toward robots (form over function) as opposed to what a lot of other folks are working on (function informs form). Look, actuators are cool and all, but that’s not the hardest part about creating useful robots!The AI part seems to be conspicuously missing from Tesla AI Day.I love that Tesla has decided to create a five-fingered hand as opposed to a two- or three-finger pincer or vacuum-based pick-and-place approach. There’s a reason why all the warehouse startups don’t use handlike manipulation mechanisms.Another Tesla robotics engineer is talking about controls in the real world and state estimation. This is coming off as a grad student/TA doing a class presentation for a bunch of undergrads. Feels very 101. None of this is cutting edge. Hire some Ph.D.s and go to some robotics conferences, Tesla: IROS 2022 is coming up in a few weeks! [ BACK TO TOP ↑ ]
Click the link under each section to jump back up to the list of experts.
Looking at the Tesla Bot as a roboticist, I am impressed by what the engineers achieved for this prototype in a year. However, the behaviors demonstrated are less impressive than that of Honda’s Asimo from 20 years ago.
What excites me is the idea of cheap and accessible hardware! The electric motors with the battery support could make a very good tool for academic research. It takes way more to solve manipulation, but Academia looks forward to getting your hardware!
The sense I’m getting is that Optimus isn’t as bad as people thought, but also, nobody [in the robotics community] is very impressed or surprised by any of the tech.
The Optimus effort is, in a sense, no different from Asimo, Atlas, T-HR3, or Digit. All of them are backed by expert roboticists with years of design experience. However, the Tesla Robotics team has done a commendable job in fast iteration time for the design of the robot from the ground up, [following the path from] a good experimental study on actuator requirements, to designing new actuators, then creating the integrated system. The current locomotion stack is not using any machine learning, but rather trajectory optimization using reference controllers. This is a sensible design choice to get up and running, but would definitely need redoing for longer-term operation.
The hand also seems exciting, with a metallic cable-driven system with four fingers and a thumb. In the brief demo, they showed it had a reasonably high loading capacity (holding plant-watering water cans, and lifting bars of aluminum in the factory). However, due to the cable-driven design, the system will have slower response time, harder to do learning-based control, and no backdrivability in autonomous mode. This will make general-purpose autonomous manipulation slightly challenging.
Robots, in the short term, have use cases in places where they do not necessarily need to interact with humans and the implications of failure are less severe. The community needs to find a revenue-positive pathway to support this development. And this could come from behind-the-scenes use cases for robot manipulation, in warehouses, retail stores, food preparation, and manufacturing. While automation-based solutions are still being pursued, it remains to be seen how a general-purpose hardware-based solution would stack up. We would need to look to low-volume, high-variability products which require quick adaptation.
Tesla would benefit a lot from collaborating with the community. Tesla already has the community taking notice, and by being more open, Elon would only empower more people to work on the problem—which is, after all, “beneficial to humanity” —which Elon claims is their driving principle. Designing the whole stack of hardware, simulation, and data infrastructure is requiring Tesla to reinvent the wheel on many fronts.
Overall, the current design is a very good first step. Interest in building such systems is welcome because Tesla and Elon Musk’s involvement in the problem brings attention, talent, and resources to the problem, setting in motion a flywheel of progress. This effort should be lauded with cautious optimism by the community, for the compass points in the right direction, and Elon brings with him the heft of Tesla engineers as we trek through the AI/Robotics jungle.
Great credit to the engineering team who pulled it off, of course, but I’m not seeing anything particularly impressive here which we can attribute specifically to Elon or Tesla. Specifically, there were lots of arguments ahead of the unveil that one or more of the “Tesla FSD stack/data/EV experience” was going to let them leapfrog all of the other companies in the space and I didn’t see any of that.
There’s also lots of credit going to Elon for saying that “it’s going to cost 20K,” which reminds me of all the 3D lidar companies that have been saying “our lidar will only cost [US] $100...if you pre-order 100K+ units.”
In short, I’d bet that any decent university or corporate robotics lab with a similar budget and an active PR team would be able to pull this off.
Optimus reveal: Mind blown with the velocity of the team and the very sleek hardware design elements. Yet to see autonomy. Surprised Tesla went full Boston Dynamics mode with classical control/planning when it’s been around for a while…
The energy and excitement at AI Day 2 was amazing. “AI Day” is actually a recruitment event, and in that sense I believe the event was a big success.
I am aware of critics who say that the prototype had nothing new that they haven’t seen elsewhere, and that there are other, more impressive humanoids. There are also people who have doubts about the aggressive timeline Elon had proposed, and I do not necessarily disagree with them.
That being said, I am a true believer of the future with humanoid robots and their eventual applications; that they will be used in our everyday lives “one day” and make our lives better. And for that to happen, we need to start somewhere and project Optimus is just that.
What was most impressive to me was what the Optimus team was able to accomplish in such a short period of time. If you are in this field, you would agree, too. The prototype they have created will serve as an excellent beginning platform for them to learn from and to build upon.
I would say this is their good first step towards something big—if Tesla truly commits to put its resources, time, and efforts into it long term. The company has great engineers, and with the newly recruited talents, I am even more excited to see what they’ll be able to accomplish next.
Am I blown away? No. Am I laughing? No.
First, the team did a good job. They came a long way in about a year(?), going from zero-to-robot from the ground up. Also, doing a live demo without a tether (safety-catch rope) is braver than people know.
Let’s talk walking. I told my lab today that I expected it to walk on stage, and it did, but I was a bit surprised at how they did it. It seems to use a method called zero-moment point to maintain balance. It’s been used in various forms since the 1990s. You see ZMP in the bent knees and how it shifts its weight over to its next foot before taking a step. It’s pretty safe, but not mind-blowing in 2022. Also, people don’t walk quite like this. We are more efficient—we stick our foot out, fall, catch, repeat.
There’s a portion showing off the vision, manipulation, and “smarts.” It’s hard for me to glean the methods here because it’s a cut video, so I don’t have much to say. I don’t know how much is pre-canned vs. online planning. I will also let everyone in on a secret about humanoids: It’s all about reliability. How often does it fall down? You can’t tell from a cool video—or even a live demo.
Musk mentioned a [US] $20K price point, which would be a big deal. The cheapest human-size humanoids I’m aware of are in the $150K range (a long way from the olden days of $1M price tags)… But I’ll believe the price when I can actually buy one.
[I was] fortunate enough to have been at the Optimus unveil in Palo Alto last night. Had a chance to check out the design and talk with many of the engineers involved.
It’s generally an old-school series chain of actuators, excepting wrists and ankles, which are differential roll/pitch. Nothing novel in the kinematics. No mechanical energy storage, parallel springs, etc.—it’s not going to be efficient unless they change that.
Two main classes [of actuators]: rotary and linear. Rotary is an integrated strain wave gear reduction (harmonic drive). Linear actuators are more interesting, integrated inverted roller screw drive. Playing with a drive, it’s not inherently very transparent—you certainly wouldn’t get a free swinging knee or hip joint. All the actuators look like they need and use active force loops. This looks nasty to me: It will complicate the control, reduce efficiency, and raise complexity. If they really want to get to [US] $20,000 a unit, this is not the way to go.
Hands: One novel feature here is a clutch on the finger flex/extend. Playing with an actual hand, it felt like it worked quite nicely to decouple the finger from the drive; this will have advantages. The design of the hands leaves very little room for a compliant (soft) layer, and bare metal hands are a terrible idea—try picking up a glass of water with two metal spoons and you will know what I mean. No finger ab/adduction, only two DOFs in the thumb—no chance of doing anything human-level dexterous here.
[Tesla has] a large team of highly capable engineers and will iterate quickly to better designs—if they can find a leader for the mechanical architecture with better ideas than they are currently showing.
The elephant in the room is the application ideas, which are frankly ridiculous. I am amazed that Musk can address an audience so rapturously enamored with the idea of a humanoid and totally fail to recognize that their desire to interact with a robot is the killer application. Did he think they were applauding because finally the world will have a humanoid robot that can lift a pipe in a car factory?
Summary: An extraordinarily brave live demonstration of a herculean effort that sadly lacks novelty and imagination. Hopefully we will see a course correction by the time of next year’s event.
The Optimus demo turned out to be a bit of a dud.
The challenge for Tesla isn’t really so much the mere fact that Boston Dynamics robots are ahead (or that Agility Robotics is also doing similar work). With enough investment, Tesla might in principle catch up. If Musk really wants to win the robotics race, he has the resources to do so. (Though he clearly has not invested nearly enough so far.)
What I didn’t see last night was vision.
I mean this in two different senses.
First, there was no clearly outlined vision for what Optimus would do, nor much justification for why Tesla is building the robot in this specific way. There was no decisive justification for why to use a humanoid robot (rather than, for example, just an arm), no clarity about the first big application, no clear go-to-market strategy, and no clear product differentiator.
Second, there was very little vision for how Tesla would build the cognitive part of the AI they will need, beyond the basics of motor control (which Boston Dynamics already does so well), nor much recognition about why robotics is so hard in the real world.
For me, the most worrisome part of last night’s presentation was not the lack of a world-beating demo, but a lack of recognition of what would even be required.
Huge kudos to the Tesla team for putting the Optimus prototype together this quickly. Clearly a world-class engineering team at the top of their game. A lot of nights and weekends there. But it’s only about 5 percent of the way to what’s being sold.
The upper body actuators have harmonic drives and the leg actuators are screw driven. Backdrivability can be added to some actuators if you also include torque sensors and close a very fast control loop around them. But it doesn’t come without adding cost and complexity to your design. Low backdrivability leaves a robot rigid to external forces. When you try to compensate for it through software control loops, you can get a telltale wobble. If you watch Optimus’s hands as it walks, you can see this wobble is in the 4-hertz range.
We were also teased with the almost finished, “almost production-ready” model. It can wiggle its fingers, but the backdrivability limitations have not been addressed. These are all tractable problems, but they’re hard. Probably not 12 months out.
I’m delighted to see such an ambitious robot project in the world! But it doesn’t help the field of robotics to over-promise. We already tried this in the ’80s, and it took us 30 years to recover.
My take on the Tesla Bot: You’re not as good as you think you are. You’re also not as bad as they think you are.
There is no “doing it first” with an all-purpose humanoid robot that can 1:1 replace people. That’s simply not where the tech is now and it’s not where it’s going to be in the next 10 years, I will say with complete confidence.
Those of us in the industry were watching to see if Tesla somehow knew something we didn’t know. And…nope. They did not. The tech isn’t there for anyone. And that’s why the more generous takes some of us try to make for the sake of the engineering team are “you did as well as you could and you’re figuring out the state of the art quickly.” It’s not that team’s fault. There was no way to achieve an impossible goal.
Here’s the thing. What humanoid robotics needs is a realistic vision. A “here is exactly where this, a humanoid form factor, is needed instead of literally anything else” vision that acknowledges the realities of the technology. But that’s not what it was. It was “today we have this, in a year we’ll have sci-fi.” And that’s just not going to happen. Frankly, it’s disappointingly un-visionary. “Everyone else just hasn’t engineered hard enough” is not a vision. It’s ignorance.
Evan Ackerman is a senior editor at IEEE Spectrum. Since 2007, he has written over 6,000 articles on robotics and technology. He has a degree in Martian geology and is excellent at playing bagpipes.
Erico Guizzo is the digital product manager at IEEE Spectrum. An IEEE Member, he is an electrical engineer by training and has a master’s degree in science writing from MIT.
The prosthetics industry is too focused on high-tech limbs that are complicated, costly, and often impractical
The author, Britt Young, holding her Ottobock bebionic bionic arm.
In Jules Verne’s 1865 novel From the Earth to the Moon, members of the fictitious Baltimore Gun Club, all disabled Civil War veterans, restlessly search for a new enemy to conquer. They had spent the war innovating new, deadlier weaponry. By the war’s end, with “not quite one arm between four persons, and exactly two legs between six,” these self-taught amputee-weaponsmiths decide to repurpose their skills toward a new projectile: a rocket ship.
The story of the Baltimore Gun Club propelling themselves to the moon is about the extraordinary masculine power of the veteran, who doesn’t simply “overcome” his disability; he derives power and ambition from it. Their “crutches, wooden legs, artificial arms, steel hooks, caoutchouc [rubber] jaws, silver craniums [and] platinum noses” don’t play leading roles in their personalities—they are merely tools on their bodies. These piecemeal men are unlikely crusaders of invention with an even more unlikely mission. And yet who better to design the next great leap in technology than men remade by technology themselves?
As Verne understood, the U.S. Civil War (during which 60,000 amputations were performed) inaugurated the modern prosthetics era in the United States, thanks to federal funding and a wave of design patents filed by entrepreneurial prosthetists. The two World Wars solidified the for-profit prosthetics industry in both the United States and Western Europe, and the ongoing War on Terror helped catapult it into a US $6 billion dollar industry across the globe. This recent investment is not, however, a result of a disproportionately large number of amputations in military conflict: Around 1,500 U.S. soldiers and 300 British soldiers lost limbs in Iraq and Afghanistan. Limb loss in the general population dwarfs those figures. In the United States alone, more than 2 million people live with limb loss, with 185,000 people receiving amputations every year. A much smaller subset—between 1,500 to 4,500 children each year—are born with limb differences or absences, myself included.
Today, the people who design prostheses tend to be well-intentioned engineers rather than amputees themselves. The fleshy stumps of the world act as repositories for these designers’ dreams of a high-tech, superhuman future. I know this because throughout my life I have been fitted with some of the most cutting-edge prosthetic devices on the market. After being born missing my left forearm, I was one of the first cohorts of infants in the United States to be fitted with a myoelectric prosthetic hand, an electronic device controlled by the wearer’s muscles tensing against sensors inside the prosthetic socket. Since then, I have donned a variety of prosthetic hands, each of them striving toward perfect fidelity of the human hand—sometimes at a cost of aesthetics, sometimes a cost of functionality, but always designed to mimic and replace what was missing.
In my lifetime, myoelectric hands have evolved from clawlike constructs to multigrip, programmable, anatomically accurate facsimiles of the human hand, most costing tens of thousands of dollars. Reporters can’t get enough of these sophisticated, multigrasping “bionic” hands with lifelike silicone skins and organic movements, the unspoken promise being that disability will soon vanish and any lost limb or organ will be replaced with an equally capable replica. Prosthetic-hand innovation is treated like a high-stakes competition to see what is technologically possible. Tyler Hayes, CEO of the prosthetics startup Atom Limbs, put it this way in a WeFunder video that helped raise $7.2 million from investors: “Every moonshot in history has started with a fair amount of crazy in it, from electricity to space travel, and Atom Limbs is no different.”
We are caught in a bionic-hand arms race. But are we making real progress? It’s time to ask who prostheses are really for, and what we hope they will actually accomplish. Each new multigrasping bionic hand tends to be more sophisticated but also more expensive than the last and less likely to be covered (even in part) by insurance. And as recent research concludes, much simpler and far less expensive prosthetic devices can perform many tasks equally well, and the fancy bionic hands, despite all of their electronic options, are rarely used for grasping.
Activity arms, such as this one manufactured by prosthetics firm Arm Dynamics, are less expensive and more durable than bionic prostheses. The attachment from prosthetic-device company Texas Assistive Devices rated for very heavy weights, allowing the author to perform exercises that would be risky or impossible with her much more expensive bebionic arm.Gabriela Hasbun; Makeup: Maria Nguyen for MAC cosmetics; Hair: Joan Laqui for Living Proof
In recent decades, the overwhelming focus of research into and development of new artificial hands has been on perfecting different types of grasps. Many of the most expensive hands on the market differentiate themselves by the number and variety of selectable prehensile grips. My own media darling of a hand, the bebionic from Ottobock, which I received in 2018, has a fist-shaped power grip, pinching grips, and one very specific mode with thumb on top of index finger for politely handing over a credit card. My 21st-century myoelectric hand seemed remarkable—until I tried using it for some routine tasks, where it proved to be more cumbersome and time consuming than if I had simply left it on the couch. I couldn’t use it to pull a door shut, for example, a task I can do with my stump. And without the extremely expensive addition of a powered wrist, I couldn’t pour oatmeal from a pot into a bowl. Performing tasks the cool bionic way, even though it mimicked having two hands, wasn’t obviously better than doing things my way, sometimes with the help of my legs and feet.
When I first spoke with Ad Spiers, lecturer in robotics and machine learning at Imperial College London, it was late at night in his office, but he was still animated about robotic hands—the current focus of his research. Spiers says the anthropomorphic robotic hand is inescapable, from the reality of today’s prosthetics to the fantasy of sci-fi and anime. “In one of my first lectures here, I showed clips of movies and cartoons and how cool filmmakers make robot hands look,” Spiers says. “In the anime Gundam, there are so many close-ups of gigantic robot hands grabbing things like massive guns. But why does it need to be a human hand? Why doesn’t the robot just have a gun for a hand?”
It’s time to ask who prostheses are really for, and what we hope they will actually accomplish.
Spiers believes that prosthetic developers are too caught up in form over function. But he has talked to enough of them to know they don’t share his point of view: “I get the feeling that people love the idea of humans being great, and that hands are what make humans quite unique.” Nearly every university robotics department Spiers visits has an anthropomorphic robot hand in development. “This is what the future looks like,” he says, and he sounds a little exasperated. “But there are often better ways.”
The vast majority of people who use a prosthetic limb are unilateral amputees—people with amputations that affect only one side of the body—and they virtually always use their dominant “fleshy” hand for delicate tasks such as picking up a cup. Both unilateral and bilateral amputees also get help from their torsos, their feet, and other objects in their environment; rarely are tasks performed by a prosthesis alone. And yet, the common clinical evaluations to determine the success of a prosthetic are based on using only the prosthetic, without the help of other body parts. Such evaluations seem designed to demonstrate what the prosthetic hand can do rather than to determine how useful it actually is in the daily life of its user. Disabled people are still not the arbiters of prosthetic standards; we are still not at the heart of design.
The Hosmer Hook [left], originally designed in 1920, is the terminal device on a body-powered design that is still used today. A hammer attachment [right] may be more effective than a gripping attachment when hammering nails into wood.Left: John Prieto/The Denver Post/Getty Images; Right: Hulton-Deutsch Collection/Corbis/Getty Images
To find out how prosthetic users live with their devices, Spiers led a study that used cameras worn on participants’ heads to record the daily actions of eight people with unilateral amputations or congenital limb differences. The study, published last year in IEEE Transactions on Medical Robotics and Bionics, included several varieties of myoelectric hands as well as body-powered systems, which use movements of the shoulder, chest, and upper arm transferred through a cable to mechanically operate a gripper at the end of a prosthesis. The research was conducted while Spiers was a research scientist at Yale University’s GRAB Lab, headed by Aaron Dollar. In addition to Dollar, he worked closely with grad student Jillian Cochran, who coauthored the study.
Watching raw footage from the study, I felt both sadness and camaraderie with the anonymous prosthesis users. The clips show the clumsiness, miscalculations, and accidental drops that are familiar to even very experienced prosthetic-hand users. Often, the prosthesis simply helps brace an object against the body to be handled by the other hand. Also apparent was how much time people spent preparing their myoelectric prostheses to carry out a task—it frequently took several extra seconds to manually or electronically rotate the wrists of their devices, line up the object to grab it just right, and work out the grip approach.The participant who hung a bottle of disinfectant spray on their “hook” hand while wiping down a kitchen counter seemed to be the one who had it all figured out.
In the study, prosthetic devices were used on average for only 19 percent of all recorded manipulations. In general, prostheses were employed in mostly nonprehensile actions, with the other, “intact” hand doing most of the grasping. The study highlighted big differences in usage between those with nonelectric, body-powered prosthetics and those with myoelectric prosthetics. For body-powered prosthetic users whose amputation was below the elbow, nearly 80 percent of prosthesis usage was nongrasping movement—pushing, pressing, pulling, hanging, and stabilizing. For myoelectric users, the device was used for grasping just 40 percent of the time.
More tellingly, body-powered users with nonelectric grippers or split hooks spent significantly less time performing tasks than did users with more complex prosthetic devices. Spiers and his team noted the fluidity and speed with which the former went about doing tasks in their homes. They were able to use their artificial hands almost instantaneously and even experience direct haptic feedback through the cable that drives such systems. The research also revealed little difference in use between myoelectric single-grasp devices and fancier myoelectric multiarticulated, multigrasp hands—except that users tended to avoid hanging objects from their multigrasp hands, seemingly out of fear of breaking them.
“We got the feeling that people with multigrasp myoelectric hands were quite tentative about their use,” says Spiers. It’s no wonder, since most myoelectric hands are priced over $20,000, are rarely approved by insurance, require frequent professional support to change grip patterns and other settings, and have costly and protracted repair processes. As prosthetic technologies become more complex and proprietary, the long-term serviceability is an increasing concern. Ideally, the device should be easily fixable by the user. And yet some prosthetic startups are pitching a subscription model, in which users continue to pay for access to repairs and support.
Despite the conclusions of his study, Spiers says the vast majority of prosthetics R&D remains focused on refining the grasping modes of expensive, high-tech bionic hands. Even beyond prosthetics, he says, manipulation studies in nonhuman primate research and robotics are overwhelmingly concerned with grasping: “Anything that isn’t grasping is just thrown away.”
TRS makes a wide variety of body-powered prosthetic attachments for different hobbies and sports. Each attachment is specialized for a particular task, and they can be easily swapped for a variety of activities. Fillauer TRS
If we’ve decided that what makes us human is our hands, and what makes the hand unique is its ability to grasp, then the only prosthetic blueprint we have is the one attached to most people’s wrists. Yet the pursuit of the ultimate five-digit grasp isn’t necessarily the logical next step. In fact, history suggests that people haven’t always been fixated on perfectly re-creating the human hand.
As recounted in the 2001 essay collection Writing on Hands: Memory and Knowledge in Early Modern Europe, ideas about the hand evolved over the centuries. “The soul is like the hand; for the hand is the instrument of instruments,” Aristotle wrote in De Anima. He reasoned that humanity was deliberately endowed with the agile and prehensile hand because only our uniquely intelligent brains could make use of it—not as a mere utensil but a tool for apprehensio, or “grasping,” the world, literally and figuratively.
More than 1,000 years later, Aristotle’s ideas resonated with artists and thinkers of the Renaissance. For Leonardo da Vinci, the hand was the brain’s mediator with the world, and he went to exceptional lengths in his dissections and illustrations of the human hand to understand its principal components. His meticulous studies of the tendons and muscles of the forearm and hand led him to conclude that “although human ingenuity makes various inventions…it will never discover inventions more beautiful, more fitting or more direct than nature, because in her inventions nothing is lacking and nothing is superfluous.”
Da Vinci’s illustrations precipitated a wave of interest in human anatomy. Yet for all of the studious rendering of the human hand by European masters, the hand was regarded more as an inspiration than as an object to be replicated by mere mortals. In fact, it was widely accepted that the intricacies of the human hand evidenced divine design. No machine, declared the Christian philosopher William Paley, is “more artificial, or more evidently so” than the flexors of the hand, suggesting deliberate design by God.
Performing tasks the cool bionic way, even though it mimicked having two hands, wasn’t obviously better than doing things my way, sometimes with the help of my legs and feet.
By the mid-1700s, with the Industrial Revolution in the global north, a more mechanistic view of the world began to emerge, and the line between living things and machines began to blur. In her 2003 article “ Eighteenth-Century Wetware,” Jessica Riskin, professor of history at Stanford University, writes, “The period between the 1730s and the 1790s was one of simulation, in which mechanicians tried earnestly to collapse the gap between animate and artificial machinery.” This period saw significant changes in the design of prosthetic limbs. While mechanical prostheses of the 16th century were weighed down with iron and springs, a 1732 body-powered prosthesis used a pulley system to flex a hand made of lightweight copper. By the late 18th century, metal was being replaced with leather, parchment, and cork—softer materials that mimicked the stuff of life.
The techno-optimism of the early 20th century brought about another change in prosthetic design, says Wolf Schweitzer, a forensic pathologist at the Zurich Institute of Forensic Medicine and an amputee. He owns a wide variety of contemporary prosthetic arms and has the necessary experience to test them. He notes that anatomically correct prosthetic hands have been carved and forged for the better part of 2,000 years. And yet, he says, the 20th century’s body-powered split hook is “more modern,” its design more willing to break the mold of the human hand.
“The body powered arm—in terms of its symbolism—(still) expresses the man-machine symbolism of an industrial society of the 1920s,” writes Schweitzer in his prosthetic arm blog, “when man was to function as clockwork cogwheel on production lines or in agriculture.” In the original 1920s design of the Hosmer Hook, a loop inside the hook was placed just for tying shoes and another just for holding cigarettes. Those designs, Ad Spiers told me, were “incredibly functional, function over form. All pieces served a specific purpose.”
Schweitzer believes that as the need for manual labor decreased over the 20th century, prostheses that were high-functioning but not naturalistic were eclipsed by a new high-tech vision of the future: “bionic” hands. In 2006, the U.S. Defense Advanced Research Projects Agency launched Revolutionizing Prosthetics, a research initiative to develop the next generation of prosthetic arms with “near-natural” control. The $100 million program produced two multi-articulating prosthetic arms (one for research and another that costs over $50,000). More importantly, it influenced the creation of other similar prosthetics, establishing the bionic hand—as the military imagined it—as the holy grail in prosthetics. Today, the multigrasp bionic hand is hegemonic, a symbol of cyborg wholeness.
And yet some prosthetic developers are pursuing a different vision. TRS, based in Boulder, Colo., is one of the few manufacturers of activity-specific prosthetic attachments, which are often more durable and more financially accessible than robotic prosthetics. These plastic and silicone attachments, which include a squishy mushroom-shaped device for push-ups, a ratcheting clamp for lifting heavy weights, and a concave fin for swimming, have helped me experience the greatest functionality I have ever gotten out of a prosthetic arm.
Such low-tech activity prostheses and body-powered prostheses perform astonishingly well, for a tiny fraction of the cost of bionic hands. They don’t look or act like human hands, and they function all the better for it. According to Schweitzer, body-powered prostheses are regularly dismissed by engineers as “arcane” or derisively called “Captain Hook.” Future bionic shoulders and elbows may make a huge difference in the lives of people missing a limb up to their shoulder, assuming those devices can be made robust and affordable. But for Schweitzer and a large percentage of users dissatisfied with their myoelectric prosthesis, the prosthetic industry has yet to provide anything fundamentally better or cheaper than body-powered prostheses.
Bionic hands seek to make disabled people “whole,” to have us participate in a world that is culturally two-handed. But it’s more important that we get to live the lives we want, with access to the tools we need, than it is to make us look like everyone else. While many limb-different people have used bionic hands to interact with the world and express themselves, the centuries-long effort to perfect the bionic hand rarely centers on our lived experiences and what we want to do in our lives.
We’ve been promised a breakthrough in prosthetic technology for the better part of 100 years now. I’m reminded of the scientific excitement around lab-grown meat, which seems simultaneously like an explosive shift and a sign of intellectual capitulation, in which political and cultural change is passed over in favor of a technological fix. With the cast of characters in the world of prosthetics—doctors, insurance companies, engineers, prosthetists, and the military—playing the same roles they have for decades, it’s nearly impossible to produce something truly revolutionary.
In the meantime, this metaphorical race to the moon is a mission that has forgotten its original concern: helping disabled people acquire and use the tools they want. There are inexpensive, accessible, low-tech prosthetics that are available right now and that need investments in innovation to further bring down costs and improve functionality. And in the United States at least, there is a broken insurance system that needs fixing. Releasing ourselves from the bionic-hand arms race can open up the possibilities of more functional designs that are more useful and affordable, and might help us bring our prosthetic aspirations back down to earth.
This article appears in the October 2022 print issue.