Prensilia says its Mia hand survived 300,000 grasp cycles at full grip force in company testing, closing in 280 milliseconds. Francesco Clemente, Managing Director of Prensilia, walks through why fingers fail before motors and gears do, why the company left tendon-driven transmissions for rigid linkages, and how it prices a 3-motor hand against lower-cost competitors. The company puts its Mia hand at $10,000 to $15,000 and its bill of materials at roughly 35% motors and close to 70% mechanical transmission and frames, by its own count.
What we cover
Why fingers break before motors or gears in a robotic hand
The move from tendon-driven transmission to rigid linkages in Prensilia’s product line
A 300,000-cycle grip force test protocol and what it does not tell you
Underactuation, degrees of freedom, and degrees of actuation explained
Bill of materials breakdown for a 3-motor dexterous hand
Customer mix across research, prosthetics, and industrial buyers
Manufacturing scale from hundreds of units a year toward volume production
“Fingers are the parts that break the most, because you have impacts with objects, you have unexpected movements from the robot.” — Francesco Clemente, Managing Director, Prensilia
“We are talking about thousands of cycles, not really millions of cycles, with the tendons.” — Francesco Clemente, Managing Director, Prensilia
“The motors account for maybe thirty five percent, more or less, of the total cost.” — Francesco Clemente, Managing Director, Prensilia
Francesco Clemente on LinkedIn
Prensilia Website
Watch on YouTube
Every episode, I sit down with the founders, researchers, and operators building physical AI worldwide, tracing the full stack from components and supply chains to what actually deploys. See all published episodes here
Chapters
00:00 Francesco Clemente, Managing Director, Prensilia
02:22 Prosthetics and research customers
04:46 Broken hands and reliability
07:09 Loaded versus unloaded cycle testing
11:59 Failure modes in fingers, gears, and motors
14:19 Motor heating and cooling
16:42 Tendon maintenance and anchoring
21:26 Weight and robotic-arm payload
23:48 Degrees of freedom and actuation
26:14 Underactuation and adaptive grasping
31:01 Motor current, torque, and heat
33:29 Grasp taxonomies and motor count
35:52 Abduction and hand design
38:17 Tactile sensing
40:38 Bill of materials and actuators
45:22 Industrial use cases
50:04 Competitors and grippers
54:42 Manufacturing scale
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Michelle Sun: Fingers are the parts that break the most. And that connection is a weak point that is gonna break. The motors are bottlenecked, and having a lot of motors inside of a small volume, it’s easy to look at spec sheets, but you have to understand that Francesco Clemente, managing director of Prensilia. Prensilia builds robotic hands out of Pisa, Italy. It’s fun out of set and in a school of Advanced Studies in 2009. Started off in prosthetics, today their hands are on humanoid robots, factory arms, and human wrists. Prensilia’s Mia hand runs three motors, closes in 280 milliseconds, which is faster than a human hand, and has survived 300,000 cycles at full grip force in testing. It sells for $10,000 to $15,000 compared to the Chinese hands at 5k. On the spec sheets, the Mia hand might look overpriced and under threat. What they’re seeing in order volume says something different. Today we’ll talk about what’s on the ground in the dexterous hand markets.
Francesco, welcome to the show. Prensilia is 17 years old today from 2009, and you are a spin off from Sant’Anna, started way before robot hands were cool, and definitely before the humanoid boom. So what did the company look like in 2009 and who paid the bills before humanoids existed as customers?
Francesco Clemente: Yes, thank you very much for having me today. I’m very excited to be here. The company, Prensilia, was founded, as you said, by researchers of the artificial enzy area that were working at the BioRobotics Institute of the Sant’Anna School of Advanced Studies. They were already working as a researcher to on the development of robotic hands and they were using developing those tools for their own research needs. Then other researchers that they were collaborating with started asking for accessing those tools, and basically here it how it came the idea to spin off a company in order to allow other researchers also to use these devices that were developed in the lab.
So the first customers were really other researchers, so universities and research centers around the world. And that let’s say research background is still with us. So today we are still working, collaborating a lot with research centers, and this is also one of the reasons why we have the specific versions of our robotic hands for research activities.
Michelle Sun: That’s amazing. And so the Mia hand came out of a prosthetic. How is the medical version similar or different from the robotics version? Did you have to change anything for the robotics customer?
Francesco Clemente: Yes. Apparently robotic hands can be used, let’s say, for prosthetics as well as for robotics today, but these two worlds are relatively different because you have very different specifications from one market to the other one. For instance, in prosthetics, you have a very clear bottleneck on the ability of the person to control the prosthesis. So you have a certain amount of degrees of freedom of movement that the person can control in a reliable way, so it doesn’t really make a lot of sense to have a 20 degrees of freedom robotic hand that can do any gesture, because the person cannot control that complexity.
On the other side, you are also limited by the weight and by the size of the device. Of course, besides prosthetics, you have specific sizes in prosthetics that you try to match. That is like small, medium, and large, I would say. The prosthesis has to be that specific size, it cannot be any size. So today we see robotic hands that have very different sizes, because of course you attach them to a robot, so it’s not super important if the robot itself and the robotic hand match in size perfectly, let’s say. But this is very important in prosthetics.
And of course another point is weight, because the person has to actively carry the prosthesis. The comfort is very important in that case, so you cannot really have a prosthesis that weighs two kilograms, because the person will be tired after one hour, let’s say, of using the prosthesis. So you really have to go down in weight in order for the prosthesis to be comfortable.
Michelle Sun: When we first spoke, you mentioned that at ICRA in Vienna earlier this year, people have been showing up at your booth carrying broken hands from other vendors. Tell me that story again. What had failed and what were the customers looking for?
Francesco Clemente: Yes, so we were at ICRA and we were meeting a lot of people at our booth. A lot of them were researchers or engineers from companies that were looking for robotic hands. And some of them were saying, okay, we are looking for robotic hands that are robust, that can be used also outside of the lab, because we were trying some other hands from competitors, but they didn’t work. We bought them because of the low price, but then we realized basically that they were not reliable for what we were going to do.
So I think that this summarizes a little bit what the status of the market is today, because there is a lot of competition, a lot of hype around robotic hands, and everyone is really working on these devices, so the demand is going higher and higher, but people are somehow approaching these devices for the first time. So they don’t really also don’t know exactly how to use them, what are the specs that are important. I mean, it’s normal, because these devices are complex. And for us that are working in the field since more than fifteen years, it’s clear what you are going to look at. But as you said before, robotics and also prosthetics was, let’s say, a niche market for robotic hands in particular a few years ago. Now everything is exploding, so people have to be accustomed also to understand the specs and what they are getting for the money.
Michelle Sun: I wanna double click on the point you make about there are things that are not on the spec sheets, right? So there’s degrees of freedom and you can also see the comparative price pretty easily. You tested Mia to three hundred thousand cycles at full force. Walk me through that protocol, because 300,000 loaded cycles and a million unloaded cycles are very different claims, and on the spec sheet it’s not easy to distinguish. Yeah, talk me through how to read through the spec sheets more efficiently and tell the differences between different hands.
Francesco Clemente: Yes. One thing that prosthetics has taught us is that we want to develop a robotic hand or a prosthesis that then can be used outside of the lab by patients and users. And also engineers, it has to be robust. Okay, so it’s easy to look at spec sheets that basically report the number of degrees of freedom, which is the kind of measure of the dexterity of the robotic hand that you’re buying, and everyone is looking into that today because they’re looking into fine manipulation protocols and solving manipulation at a higher level.
And of course you want to have something that is similar to the human hand in terms of movements that you can perform, but you have to understand that that comes with a cost associated. So the device becomes very, very complex. You either have a very bulky forearm that hosts all of the motors, with tendons that drive the fingers and the joints, or you have very small motors inside of the hand, inside of the joints of the fingers. And this means that the performance will have to be low because of the size of the motors that you’re using. So reliability is something that you have to compromise, also with dexterity, let’s say.
So we really pointed to have, tried to achieve, high robustness with our devices, and this is the reason why we basically developed a test protocol where we would run several thousand cycles at full force in order to really understand if people could use the device at the specs that are reported in the spec sheet. Okay, because if you say, okay, my hand can perform this type of grasps and this amount of force, 50 newton grip force, you have to know how many grasps you can really do at that amount of grip force, you know? Because you can test it at no load. But of course that’s not a measurement, or let’s say a parameter, that tells you in the real world how much the device is going to last.
Michelle Sun: If we do the math for, let’s say, the cost per grasp cycle, the Mia hand is ten to fifteen thousand dollars and the hand at the ICRA show probably around five thousand. How many cycles does that other hand last? And on a per grasp cycle basis, which one is actually cheaper?
Francesco Clemente: Well, it’s very difficult to tell a number for competitors, let’s say, because you really have to get the device and test it to know for sure, let’s say. But the thing is that there are two points. One is the grip force that you can get with those devices, that is relatively lower. So in general you also have maximum performance that’s capped because of how the device is designed. So if you have more motors, usually you have a lower grip force, this means that also for single grips you have a lower performance. And on the other side, of course, if you run at full grasp, you probably get a shorter and shorter lifespan.
So I can say for the competitors, okay, they will last 100,000 cycles or whatever, but the problem is that, what they reported to me is the fact that the performance was too low to carry out a large amount of tasks. And also, in the tasks where they were using the hand, they were still breaking, even if those tasks were relatively light, let’s say. So also moving cans, empty cans, let’s say, would be a relatively problem for those devices.
Michelle Sun: When you say that a hand starts breaking, are we thinking about the motors overheating, or actually like some of the fingers fall off? Or tell me more about the failure modes when it comes to, at the end of the 300,000 cycles, or in a competitor’s hand, a hundred thousand cycles, what would be the breaking point of the dexterous hand?
Francesco Clemente: Yeah, there is a lot of stuff that can break in a robotic hand. So one of the reasons why we try to limit the amount of motors in joints, it’s also to reduce complexity in order to have less stuff that can break, let’s say. But in general, of course, fingers are the parts that break the most, because you have impacts with objects, you have unexpected movements from the robot, so they are the most exposed part, I would say. So it’s important to have a device that allows you also to replace relatively quickly the fingers or the fingertips in order to service the hand in a relatively quick way. And this is, I would say, one problem that we also have and that we solved in this way, basically with a quick-release mechanism that allows you to replace the more distal part of the finger in a quick way, from a user perspective.
On the other side, of course, when you run a lot of cycles, you start to have wear of the components. So we have gears inside of our device, and these wear out because of friction. So at some point you will have to replace some components. First, I mean, usually you don’t have a dramatic, sudden break of the component, but you start having more mechanical play in the transmission. And then at some point, of course, the component is worn out too much, so that it basically breaks.
Another point that is very important is related to the motors. So the motors are the bottleneck in the mechanical transmission for several reasons. One is the one that you were mentioning before, so one is overheating. So electric motors heat a lot, and having a lot of motors inside of a small volume basically means that you need to have some sort of cooling system.
So if you look at the shadow robotic hand, that is this anthropomorphic robotic hand that was available since twenty years, they have a large forearm where they put the motors, and then with the tendon system they run the fingers, they have fans on the forearm in order to pull down the motors. So this is a problem that was there since all the time, let’s say, so it’s not a new problem, let’s say. So if instead you are putting the motors in the fingertip or in the joints, the problem is that you don’t really have a space to put fans there. And the motors, the smaller they get, the more they heat, because the surface area of the case of the motor is smaller. So the capacity to transfer heat outside decreases a lot with their volume and surface area, let’s say. So what happens is that sometimes you have to stop using the device in order to wait for the device to cool.
This is again one other reason for us to use less motors, bigger ones, so that they have less heating issues, let’s say. Just very quickly, another point is the gearhead of the motor that also limits the torque that the motor can provide to the system. So another point that can break is really the gearhead of the motor. So if you are pushing the motor to the limit, the structural components of the motor can fail at some point.
Michelle Sun: So it seems like there are four key areas that the hands can fail. The fingers can fall off on its own. And then there’s the motors wearing off after too many cycles. And the motors overheating is another one. And the last one is about the gears.
Francesco Clemente: Right. The gearheads. So the gears that are inside of the motor, let’s say, or coupled directly to the motor. So the last one is the gearheads within the motors being worn out because of too many cycles.
Michelle Sun: It’s interesting you mentioned Shadow. That’s actually my next question. You spent a decade building tendon-driven hands, the IH2 Azzurra, 11 degrees of freedom. And then you decided to remove tendons. Shadow used tendons for 20 years and half of the industry roadmap is still using tendons. What was the reason behind this design decision? Is that the cycles, tension lost, or is it really expensive to service?
Francesco Clemente: That’s a very good question. So tendons, we think tendons are great because they provide you a lot of flexibility in terms of design flexibility. So you really can move the motors around, because you can use the tendon to transfer motion from the motor to the fingers. So you have the ability to have more freedom of where to put the motors inside of your device.
Also, one of the reasons why they were used a lot is when you have a lot of motors, so that you can really store them in a more convenient way, and transfer motion with tendons in a very simple way around. But on the other side, the main problem of the tendons is, first, the fact that they usually break. I mean, tendons themselves are not a problem. I mean, tendons are also used in airplanes for controlling some components of the wings, so they’re not a problem by themselves. But the problem is that when you put them inside of a robotic hand, you have a very small amount of space available to make a tensioning system that is robust enough to be used correctly for a lot of cycles.
And specifically, tendons need a lot of maintenance. So the problem is again not with the tendons themselves but with how you anchor the tendon to the transmission. So the anchoring points are usually weak points. You can make a knot, you can use sleeves in order to connect the tendon to the mechanical transmission, let’s say, and that connection is a weak point that is gonna break. So even if the tendon is, let’s say, rated to hold one hundred fifty newtons, after a few cycles it will hold probably a hundred newtons. So they’re not very good with a large amount of cycles.
So we are talking about thousands of cycles, not really millions of cycles, with the tendons. And this is one of the main reasons why we moved to gears and links. Of course, gears are more reliable on this scale, I would say. They have the disadvantage that you have less freedom, because you cannot have a gear of any size, of any shape, you cannot transfer motion at any angle, let’s say, so you are more constrained. So you can do less, let’s say, with these tools.
Michelle Sun: So where does the anchor points fit? So you mentioned that there are all these tendons, and then there are points that are the failure points, right? The anchor points are usually where the problems start to appear. Are they within the knuckles area in each of the fingers, or where do you usually hide the anchors?
Francesco Clemente: We have one hand that is called IH2 Azzurra that is driven by tendons. So these tendons are anchored to the mechanical transmission on two sides. On one side is in the palm, because in the palm we have the motors, so we have a mechanism that basically pulls the tendon. So on one side the tendon is connected there in the palm. And on the other side is at the fingertip. So basically the tendon runs through the joints of the finger and then anchors to the back of the fingertip, so that when you pull the tendon, the finger will close. And when you release the tendon, the finger will open because of a spring inside of the joints. Usually, let’s say by generalizing, one point is before the joint that you want to move, usually close to the motor, and the other point is beyond the joint that you want to move. So at the fingertip, or let’s say between the metacarpophalangeal joint and the proximal interphalangeal joint, if that joint is the one that you want to move.
Michelle Sun: I noticed that the Shadow hand with the forearm units included is around four point three kilograms. Versus the Mia hand, with three motors inside the palm, is around a tenth of the weight. Walk me through the math when it comes to the weight and the performance that comes with it.
Francesco Clemente: Yes, of course. So weight is of course one of the important parameters when you want to design a robotic hand in general, so specifically for prosthetics, but in general for robotic hands, you need to set a certain weight. Of course, the Mia hand and the Shadow hand are very different devices, no? So three motors versus 20 plus motors. This comes with a set of different specifications and complexities of the device.
For us, the motor is one of the heaviest components that is inside of the hand. So one way to reduce the weight of the device was to limit the amount of motors that were inside of the device. So what does this mean? Basically, in this way you are setting the limits for the use cases in which you can use your device. Okay, so if your device weighs five hundred grams, it means that you can integrate it also in robotic arms that can carry up to three kilograms. So you will lose half a kilo for the end effector, but you still have two point five kilos for the application. You can use it in prosthetics. On the other side, if your device weighs five kilos, four kilos, you need at least a robotic arm that has a payload of ten kilograms, because if you use a robotic arm with a five kilogram payload, you basically don’t have any additional payload for the task that you need to do.
So it really sets the basis for the set of applications that you need to perform, that you can perform with your device.
Michelle Sun: Speaking of applications, so would you say that the Shadow hand is designed for a different set of applications versus a Mia hand? And what would those two categories be?
Francesco Clemente: Yes. So we designed the Mia hand specifically for prosthetics, and then we reengineered the device, modified the device in order to have also an industrial version. So we have two versions of the device, again, one for prosthetic users and one for industrial settings, so for automating processes in the industry. The Shadow hand is more of a research tool. So far as my knowledge goes, I’ve never seen that robotic hand used in an industrial setting. Of course it’s not usable in a prosthesis, as a prosthesis, but it really targets research settings, where you have capabilities to control the device that are, let’s say, not normal, I would say, because the device is very difficult to use, because you have to control 20 degrees of freedom all at once. Of course it’s becoming more and more simple thanks to AI. So AI is simplifying the use of more complex tools also in more standard settings, I would say. But as far as I know, that amount of complexity is still something that is used more in research settings.
Michelle Sun: That makes sense. And we’re getting to the audience favorite term, degrees of freedom. So everyone is obsessed about how many degrees of freedom, like our human arm has, a hand has, and the tool that you gave me last time was active versus passive degree of freedom. Tell me more about that, and how to read a spec sheet when it says, hey, there’s twenty degrees of freedom on this hand. How many motors are actually there? How many joints are just following along with the motor? Walk me through this vocabulary set of degrees of freedom.
Francesco Clemente: Yes, there is a little bit of confusion there, because degrees of freedom is a general term and then everyone is using it in a bit different way. One way to look at it is using degrees of freedom versus degrees of actuation, where degrees of freedom is number of joints and degrees of actuation is number of motors, or, as you said, passive and active degrees of freedom. So passive ones are the ones that are not controlled directly by a motor, while active ones do. This is the difference between the two.
So why do we have this difference? Because, for instance, if we take a robotic arm, we generally have six joints, six motors, one joint, one motor, and it’s very simple, let’s say. On the other side, in robotic hands, since several years, researchers have been exploring other ways to develop robotic hands, and one way is through underactuation. So underactuation means that the number of joints is larger than the number of motors that drive those joints. And the main reason for this is exactly to reduce the amount of complexity of the device, in some way also to increase the performance. Okay, because one way is the number of movements that you can do, but then you again have grip force, speed, weight, and all of the other performance metrics that you have to compare with and also kind of balance, let’s say.
In this case, what happens if you have less motors than joints, it means that these joints have to be coupled somehow together. Okay, so for instance, in Mia we have three motors that are used to actuate the flexion extension of the thumb, the flexion extension of the index finger, and then the last three fingers are coupled together. So you have three joints, but basically only one motor that controls those joints. And this limits the complexity of the device. This is one way, relatively simple way, to control different joints with a motor, basically with a rigid mechanical transmission.
On the other side, in Azzurra, for example, we have one motor per finger, but one finger has two joints. So we have one tendon that basically wraps around these two joints per finger, and then is used to control both joints simultaneously. This underactuation allows the finger to also wrap around the object and provide some flexibility. So rather than having a rigid transmission between these two joints, we have the tendon and springs inside. This basically allows for the proximal phalanx, in case the proximal phalanx encounters an object, the second phalanx can still continue to flex and adapt to the shape of the object. This flexibility is actually called underactuation and is, let’s say, a smart mechanical system that allows you to still have some adaptability of the shape of the hand to the object without having to actively control all of the degrees of freedom, so all of the joints independently.
Michelle Sun: Got it, got it. So there’s underactuated, when it comes to underactuated hands, then that means that the degrees of freedom is more than the number of motors, the actuators. Which sounds great when it comes to like less overheating, less weight, and less complexity. Is Azzurra also underactuated?
Francesco Clemente: Yes. Because it has eleven degrees of freedom and five motors.
Michelle Sun: I see. And then Mia hand, how many degrees of freedom, and three motors?
Francesco Clemente: That’s six degrees of freedom.
Michelle Sun: Six. Okay. And in theory that sounds great, right? Why wouldn’t all hands do that? Like what is the reason for people to wanna have, is there something like overactuated hands, or, you know, just what’s the opposite of an underactuated hand?
Francesco Clemente: The opposite is, let’s say, fully actuated. So for each joint you have one motor. And this, of course, is the simplest way to develop a robot. So for each joint you have an actuator, and you also have this direct driving, you know, let’s say. The problem, let’s say, with this, and specifically with this setup in a robotic hand, is the compromise that you have to make while choosing the motor and while choosing the performance, let’s say, of your hand, as we said before. You basically have two choices. You end up either having very small motors inside of the joints, because the joints and the fingers are very small, or you need to use some kind of mechanical transmission, like tendons, to have a remote actuation system and then transfer motion. Of course, this allows you to use larger motors, but the device becomes relatively bulky and heavy.
Michelle Sun: And so for Mia hand you use tendons that connect the motors to make it more degrees of freedom than the motors?
Francesco Clemente: No, no, for Mia hand we use rigid mechanical transmission, so linkage.
Michelle Sun: Azzurra hand?
Francesco Clemente: Yeah, that’s the third, yeah.
Michelle Sun: Azzurra, you use tendons?
Francesco Clemente: Yes, correct.
Michelle Sun: Yep. Yeah, makes sense. And you told me that a lot of these motors run five, ten minutes before they need a cooldown. How does a buyer look at the spec, is it possible to look at the spec sheet and know about this mechanism, like the cooldown performance? Is that something that people just don’t publish on the spec sheets?
Francesco Clemente: Yeah, this is very tricky. The problem is that it’s difficult to know from a spec sheet. The reason is that you don’t usually publish heating performance, dissipation performance, of your robotic system. Okay, this is linked to the fact that motors are designed with several parameters. They can run continuously at a specific, when they produce a specific torque. So if you provide a certain nominal current, this current can be provided continuously, and the torque that is generated can be generated continuously. So the motor can run without any stop or without any problem.
The fact is that electrical motors can be provided also with more current than this nominal one. The maximum current that you can provide is called stall current. So when the motor is not moving, you can provide the maximum amount of current, and the motor can generate the maximum amount of torque. Of course, you want to have this torque, because it’s much larger, so two to twenty times larger than the nominal one. So in order to have meaningful performance, you need to exploit these larger currents and torques, but the motor cannot handle these currents for a long amount of time. So this is the reason why you have to stop using it at one hundred percent after some time, because the motor itself cannot dissipate all of that heat that is generated.
So this is something that is well known in the field, and this is the reason why robotic arms are so big, you know, relatively to grippers, because the motors are, let’s say, oversized with respect to the torque that they would actually generate. So they are used at, let’s say, thirty percent maximum performance in order to avoid these issues and be able to run the robotic arm continuously. On the other side, robotic hands are very challenging at the moment. So we don’t really have technologies that allow us to use robotic hands at 30%, 20% of their maximum performance. So it really hits with these heating issues that come up all the time, I would say.
So for a customer it’s very difficult to know this, and I think that you really learn this by experience. So as a researcher that was working with these devices for several years, I’ve seen a lot of these hands, in general also grippers, more advanced grippers with very small joints, run into heating issues, and this is something that we were trying to design for during the years, but it’s something that’s not given for granted.
Michelle Sun: If you were designing the hand for a humanoid that ships ten thousand units or more in a couple of years, how many motors does it have?
Francesco Clemente: That’s a very difficult question. So the question of scalability is an important one. Again, we think that a system, an engineering system, in order to be optimal for the task, has to be sized for that task. I mean, you can design a robotic hand that has 20 motors that of course can perform a lot of movements, but it’s very difficult to scale from an industrial perspective. Okay, so our idea also when developing the Mia hand, and also with new devices that we are developing, is to study grasp taxonomies, because there are several research studies in the field that study grasp taxonomies. We basically study the shape of the human hand while doing tasks, and say, okay, we have the cylindrical grip, the pinch grip, the lateral grip, that are basically grips that are used more often or less often during activities of daily living.
And try to engineer a system that basically covers most of the grasps that are used in doing the activities of daily living. So in this way, you design a device that can perform, let’s say, 90% of the activities of daily living, reducing cost and complexity by 80%, I would say. So I really think that the Mia hand has some limitations, so the fact that you only have three motors, also the fact that these motors can be used all for the thumb position, you only have two positions for the thumb position, so whether it’s opposed or open, you cannot control it actively. It’s a little bit of a limitation for some of the tasks that are required, but probably five motors are a number that I would bet for a robotic hand that is cheap enough to be scaled also from a manufacturing point of view and also a robustness point of view.
Michelle Sun: Interesting. So Mia hand has three motors. Where would the two additional motors be added?
Francesco Clemente: Okay, one could be, of course, on the thumb opposition, because at the moment, I said before that the Mia hand has three motors, one on the flexion of the thumb, flexion of the index, and then the last three fingers are coupled together. Actually the motor that moves the flexion of the index is also coupled with opposition of the thumb, so that with a single motor and a special patented mechanism you can perform the cylindrical grip, but also you can oppose, you can open the thumb, so that you can perform also the lateral grasp. So this movement is coupled with this movement. So when the index finger extends completely, you can move this other joint, let’s say. We would probably decouple those in order to be able to add these independent ones, so that you have a little bit more flexibility and also have a little bit of in-hand manipulation capability.
Probably the other one I would still put in abduction rather than flexion, because there are also studies in the research literature that basically say that having a hand that is able to have abduction movements and two to three degrees of freedom in the flexion of the fingers is equivalent to having a twenty degrees of freedom hand without abduction. So abduction is very important, because it allows the fingers to align, in order to have, so the thumb with the long fingers to align, in order to have a much more stable grasp.
Michelle Sun: I like that. It’s a live design session right here. And you highlight a really important point when it comes to what is the optimal performance level that is also easy to make industrial, on an industrial setting, in mass production, and balancing all these different factors, not just on the spec sheet, like what it looks nice when it comes to the numbers of degrees of freedom. And there’s been a lot of talk about tactile skin, tactile sensors. What are your thoughts about that? They’re not easy to make. They’re very technical and they can be quite bulky as well, depending on what type of tactile sensor that is. Is tactile sensing a prerequisite for these dexterous hands, or do you see that as a luxury?
Francesco Clemente: Probably the best answer from my side is that I don’t really know. I don’t know how much we know about this. So there is a lot of activity going on that demands tactile sensing and very rich tactile information that you use to do dexterous in-hand manipulation. And this, of course, is a specific, let’s say, activity in the manipulation, and in trying to get to something that resembles the human hand. How much this is needed for the tasks that we have to do in, let’s say, an industrial setting, I don’t know. But of course I understand the point of people that want to go deeper into that.
In our devices, we try to have also a balanced approach in this way. We have different amounts of sensors. Some of them are simpler ones. These are basically load cells that are inside of the fingers. So the fact of having the sensors inside of the fingers and not on the fingertip, on the external part, makes them more robust, because not being at the interface with the object, the sensor does not wear out during grasping, so the sensor lifespan is increased. On the other side, it’s more difficult to get position information, so spatial information about the location of the contact point between the finger and the object. For this, you really need a matrix of tactile sensors that are on the fingertip, and this is something that you cannot really go around.
We have partnered with Touchlab, which is a UK company that develops some of the sensors that tie inside of our hands, and that work very well. For instance, we have developed the Mia hand with these sensors, with a matrix of tactile sensors on the thumb, and this allows for richer, let’s say, information to come out from the hand. From a deployment point of view, there is a lot of discussion about the fact that if these sensors are required in, let’s say, a teaching phase of the robot, and then when you deploy the robot, maybe you need simpler sensors, or no sensors, in order to perform the task in a continuous way. But this is something that is still to be discussed and understood.
Michelle Sun: Interesting. Did you mention that the Mia hand doesn’t have tactile sensor on the fingertip, but on other parts of the hand? And did you mention that there’s also sensor on the thumb?
Francesco Clemente: Yes, correct. So the Mia hand has load cells in the thumb, index, and middle finger, at the base of the finger. And then this part, or, yes, at the proximal part of the fingers, I would say, and this allows for the sensors to be sensitive on the whole finger. So it’s not important where you’re touching, the sensor will still pick up deformation. But as I said before, on the other side, you don’t know the location of the contact point.
Michelle Sun: Very cool. If you take the Mia hand apart on a table with all the parts that go into it, motors, gears, sensors, machine parts, can you walk me through, let’s say, the three actuators, like how many, what’s the percentage of the bill of materials that it costs, and what is the most expensive line item in the hand?
Francesco Clemente: Yeah, the most expensive line item, I will say that the motors and the force sensors, so those are the two most expensive ones. Then the mechanical components are, of course, accounting for probably 70% of the cost. So most of the cost is mechanical transmission and the frames of the device. And then you have the electronic components, the PCBs, those ones really are much cheaper to do also at a larger scale, so they don’t really account for a lot of cost in the bill of materials. But of course the motors and advanced sensors, for instance the ones that are a matrix of tactile sensors, I would say, are the most expensive ones.
Michelle Sun: For the semi percent of the transmission related costs, how much of that would be the three actuators and the sensors?
Francesco Clemente: On top of my mind I would say that the motors account for maybe thirty five percent, more or less, of the total cost. Well, we don’t have a lot of motors, so for hands that have a lot of motors this number goes up a lot.
Michelle Sun: I mean, thirty five percent is actually not that out of the range when it comes to like the numbers that I’ve been seeing, like forty to sixty percent of a humanoid is actuators. I’m assuming another bulk of it would maybe, another twenty percent is the touch sensors. Is that how you’re seeing it?
Francesco Clemente: Yes, more or less.
Michelle Sun: And where do these motors and gearboxes come from? You mentioned that you work with Touchlab for the touch sensors. Do you also work with a European supply chain when it comes to these hand scale actuators, or are you sourcing from Shenzhen?
Francesco Clemente: No, we use suppliers from Europe for the motors, because we basically could not find a replacement for these motors that was keeping pace with the performance. So we never switched to other solutions.
Michelle Sun: I see. So the European supplier that you have is able to give you off-the-shelf actuators that can be replaced pretty quickly. Or did you have to do modification in-house to fit the motor for the Mia hand?
Francesco Clemente: No, no, we use off-the-shelf actuators, actually. So usually the motor suppliers have a catalog of motors and gearheads that you can combine together. So basically what we do during design is combine motors plus gearhead, in order to have the best combination to get the torque and the speed that is needed for the application. We have a little bit of customization that we sometimes discuss with the suppliers, but it usually only gets down to the size of the output shaft, or the shape of the output shaft, in order to be able to connect more easily the motor to the rest of the mechanical transmission.
Michelle Sun: Who actually buys a Mia hand today? Who are your customers? How do they split between prosthetics, industrial sales, humanoids, and research labs?
Francesco Clemente: Yes. So at the moment we started selling Mia hand as a research device as well. So before it was also CE marked. Most of our customers are still in the research space. We CE marked Mia hand at the beginning of twenty twenty five. So at the moment the hand is CE marked both as a prosthesis and as an industrial gripper. I would say that we still have at the moment more customers from the prosthetic side, and the industrial side is coming out later. I would say fifty percent research, thirty five prosthetics, and fifteen percent industrial. We are now pushing a lot on the industrial side, because we believe that’s an early adoption market in that case, because industry is not really used to using robotic hands, but they’re accustomed with grippers, but we see rising demand for more flexibility. So we want to push on that.
Michelle Sun: Do you have any visibility in terms of what kind of industrial task your customers use Mia hand for? And what are the customer profiles of these industrial customers? If you were to point at one particular deployment task out in the world and say, hey, this is what actually pays the bills, and what you see as the biggest growth area for Mia hands, which one would it be?
Francesco Clemente: Yes, we are very excited about two use cases. One is testing of human machine interfaces. So all of those objects and goods that have a human machine interface that is designed to be used with the human hand, so by humans, like the interior of cars, so in the automotive sector, at the moment you have at the end of the line a person that goes inside of the car and tests the interior of the car. This can really be automated with a device like Mia hand, that is lightweight and can fit together with a robotic arm inside of the car, and be used to test all of these components. But also like medical devices, like ultrasound machines, ekographs, that have keyboards and mice, that have these interfaces that are relatively advanced, not just simple buttons, but big buttons, levers, a mouse, and also a touch screen. So here we see that Mia hand can be used because of its flexibility, and you cannot really use a simple push-button gripper, let’s say.
And the other one is HoReCa, so hotelier, restaurants, and catering. So serving food and preparing food. In that case, we think that both the flexibility of the device and also the aesthetics of the device are very important, because you have to interact with very different objects while serving food and preparing food. On the other side, you are also in contact with the general public, so this is something, so also aesthetics is very important. We have worked with partners in the past in order to develop robotic cells that prepare ice cream or serve you food, and this is also something that we look for.
Michelle Sun: With Oversonic, the Italian humanoid customer, they use your hand on the robots. Walk me through how that actually happened, from the first email to the first production order. How long does it take, and how many units do they eventually buy?
Francesco Clemente: Yes, Oversonic is an Italian company that develops humanoid robots. So there are not a lot of Italian companies that develop humanoid robots, and there are not a lot of Italian companies that develop robotic hands. So it was relatively simple for us to get in contact. I think that one of the first contacts we got was at an industrial fair in Bologna, so we met them there, and we started discussing possible collaborations, because they found the development of the robotic hand to be very difficult, and we already had a device that could be fitted to the robot. So they were happy to discuss collaboration with us. So they have, at the moment, different use cases.
The one they are exploring the robotic hand, so Mia hand, the most, is with their medical version of the robot. So they have a medical version of Robee, that is the name of their robot, that is used inside of hospitals to support rehabilitation therapies inside of the hospital. So also in that case you need, it’s not an industrial setting, but you need flexibility in order to interact with patients, interact with different objects, rehabilitation devices, let’s say. They were looking for somebody that was resembling the shape of the human hand and that would provide the flexibility in the grasping and manipulation that Mia hand could provide. In this way basically we found this use case that was interesting for them, and they were basically deploying some of their robots in their first pilots inside of this use case.
Michelle Sun: Amazing. Seems like this medical and hospital use is a recurring theme that you mentioned, about like ultrasound machines, and then with Oversonic as well. If we zoom out on the whole dexterous hand market, Psionic also works on prosthetic hands like yourself, and now their Ability Hand sells into robotics, also around like fifteen to twenty thousand dollars. Inspire Robotics got a lot of humanoids using them. And then Shadow, you mentioned, sells mostly into research institutions. And then there’s also Robotiq in Canada that owns the industrial grippers segment. Who do you see as your competitor, and who’s in a completely different business that just looks similar on the form factor?
Francesco Clemente: From an industrial point of view, I think that from the people that you’ve mentioned, let’s say that the Shadow robotic hand is a little bit different with respect to the other ones, because as far as I know, as far as what I see, they’re very much focused on research only. So they’re not selling their device to be used in industry and in prosthetics. So that’s relatively different. And also the hand is very much different from the devices that we develop, so there is also a matter of really different specifications between the two.
Of course, the Ability Hand is the closest one to us, so that’s, of course, a competitor for us. I think that our devices are a little bit different, with different specific strengths and weaknesses, but definitely we are playing in the same space. Robotiq, that you mentioned, is, of course, one of the largest gripper manufacturers in the world. They focus a lot on standard industrial grippers. So again, Robotiq or Schunk or these kind of people, so they have a very strong market in the industrial settings, let’s say. What we would like to do is complement their offering with something that is more flexible. Okay, so our competitors, meaning that probably the clients in the industrial settings that they have and the clients that we have are the same, but we are offering something different.
So let’s say that the device that we offer is complementary with respect to the standard gripper, because the standard gripper is something that is great if you need no flexibility, but you need very high performance, so very fast, very strong, very repeatable, and that’s it. But you only can grip, let’s say, a single object. While we are providing something that is more flexible, still industrial grade, but lower in performance. So we are not able to match the grip force and the speed of a gripper, because that’s a very specialized tool.
Michelle Sun: And it seems like it’s a different performance and different use case as well. So when it comes to grippers, it’s about picking one thing to another place mostly, versus when you mentioned about the use cases that you see, the two main ones with HoReCa and also the human interface, is more about more delicate objects, or you touch some screens or moving a joystick in the ultrasound machine. So is that how you think about it? Like the gripping part, like pick and place mechanism, belongs to the gripper form factor, versus the Mia hand is able to do something that is more about, for example, touching a screen or testing the automotive interior, that needs more of a grip, finger based grip sensation, like action.
Francesco Clemente: Yes, this is one way to think about it. So it’s the specificity of the gripper, so the fact that it’s very much designed for pick and place and for moving objects quickly, while Mia hand, of course, it’s more flexible, so that you can do different things in a specific use case. But not only that, the flexibility comes down to the flexibility of the device. So on one side the gripper is usually designed to be used, so from the start to the end of its lifetime, for the same activity. So you design the fingers of the gripper in order to pick a specific object, because you want it to grip that thing and do that without changing it. While on the other side, a hand, the fact that it’s a hand, gives the device more flexibility. So this device is designed in order to be also relocated to different tasks, so not doing the same thing over and over again. But let’s say, okay, today I need to do these tasks, in two months I need to do something else, and this is something that is enabled by the flexibility of the device.
Michelle Sun: My last question is, when you think about owning that market when it comes to complementing the industrial grippers and supplying to these industrial use cases at scale, what are the biggest blockers when it comes to the manufacturing side? Do you see yourself needing to find, like, a different supplier to build a Mia hand at tens of thousands or hundreds of thousands at volume? Walk me through that future.
Francesco Clemente: Yes, of course, this is something that we are looking into at the moment. So at the moment, Prensilia is basically a design firm. So we have a strong engineering team that designs all of the components, and we outsource the production. And on the other side, we get all of the components, assemble, and do the quality tests in-house. And this allows us to ensure a good quality of the device. Of course, this can run up to a certain scale, let’s say hundreds of hands per year. But if we would have to go to thousands of devices per year, then we need to probably change approach. We are already looking into this in two ways, let’s say: redesigning some of the components in order to use manufacturing processes that allow us to scale production from a manufacturing point of view, but also partnering with partners that help us, let’s say, with assembling part of the device, in order to be able also to scale manufacturing capabilities on our side. So we think that we are not gonna solve this by ourselves, but we are now partnering with strong partners that are specialized in manufacturing, in order to be able to scale production and meet the demand that seems to be needed for the next years.
Michelle Sun: Awesome. Well, thank you so much, Francesco. This is amazing, to chat with you about everything from the design and the mechanism that goes into dexterous hands, but also the market that you’re seeing on the ground. Thank you so much for joining today.
Francesco Clemente: Thank you. I mean, it was a pleasure.
