Video Otherlab Working on a 'Fundamental Jump' in Technology for Exoskeletons (Video) 36
Tim: Tim, we’re here at your booth here at the O'Reilly Solid Conference with the Otherlab Orthotics, so what is Otherlab Orthotics?
Tim Swift: So Otherlab Orthotics is we’re developing a fundamental technology for exoskeletons, essentially orthotics are powered orthotic devices. What we’re making is, we’re making all fabric insulated orthotics. This is an elbow brace, it’s kind of an initial prototype, but the value of these is they are an order of magnitude reduction in cost and weight for comparable power capabilities in conventional exoskeletons.
Tim: Now the fact that you’re using soft materials is a little bit counterintuitive because I think of an exoskeleton as being a hard, rigid assembly.
Tim Swift: Yeah, just trust me, you’re not the first one, there are a lot of people actually who that’s exactly the case, is that is the, that’s the concept of what exoskeletons are and it’s actually one of the reasons why I use the term orthotics instead of exoskeleton is because while these are known as exoskeletons, we are not hard on the outside, so we kind of break that norm. But if you think of all of the advances that have come in the exoskeleton world, every advancement has come by making a smaller device than what they made previously and at this point the only device that’s ever been shown to positively impact dynamic capabilities in human is a 600 gram little tiny electro-mechanical ankle thing and so all of these push towards smaller, smaller lighter but key power, that’s fundamentally limited with conventional technologies.
Tim: Can you talk about what makes yours lighter in particular?
Tim Swift: Yeah. So, a lot of the benefits of these come in a fact of using high shrink fabric materials and so you can see, this is actually made out of a ballistic nylon. It should be known that the ballistics is marketing and marketing only. This is the material you’d make like a backpack out of, it’s as simple as it comes, but the strength to weight ratio of this material is comparable to steel and so you can get something extremely cheap and still have the strength that you get out of kind of more conventional and traditional construction materials.
Tim: What about the actual bladder inside, what is that made of?
Tim Swift: So the bladder is, the construction of this is – so it’s two layer, right, there’s the outer layer which is a high strength and an inner layer, and a polyurethane bladder at this point, but it’s this kind of structured material are set up, but it’s really conventional, it’s similar to like a bike tire, the way you’d construct that, right, you have a high strength material in the outside, you have an airtight material in the inside and we use that to build up what the structures are.
Tim: Well, let’s walk over to your little booth here and talk about the way you get the air inside.
Tim Swift: All right.
Tim: In fact, it looks like something out of a like a crazy scuba gear shop here.
Tim Swift: Yes, sadly enough.
Tim: What sort of pressures are we talking about here?
Tim Swift: So, these actually run at totally reasonable pressure, so the device here at 20 psi you’re getting about 25% of the power of a normal human elbow. That’s a very easy to generate amount of pressure. We are actively looking at this is an initial prototype of a custom compressor that we’re building, it’s a roll diaphragm compressor, and essentially this is set up to do exactly kind of create this new space of lightweight efficient mobile pneumatic tool or components. The area of hydraulic components and electromechanical components for the last 40 years has been heavily developed before the advent of robots and mobile technologies like that, and pneumatics has been honestly kind of left to the wayside because people have assumed that they weren’t a viable medium. We believe that that’s not the case; in fact, we actually believe that a lot of the reason that pneumatics doesn’t stack up very well in conventionally uses is because it’s traditionally used like hydraulic system, but it’s not actually well suited to be used that way and so what we’re basically doing is, looking at building the infrastructure pieces to get the efficiencies of a pneumatic system to where we think that that we can get them.
Tim: Let me ask you one more question?
Tim Swift: All right.
Tim: The uses include rehabilitation linked to physical therapy, maybe you have a bad joint?
Tim Swift: Yeah, of course.
Tim: What else?
Tim Swift: So, I think the easy way to capture where these can be used is we are early, we know that, everybody who’s looking at this can tell that. But we’re not trying to create a niche solution to a single problem. This is a fork in the road for an exoskeleton design. And so essentially what that means is every place that conventional exoskeletons can be used, medical applications, limited in kind of strength in applications for military, lift assist, things like that, this technology is applicable. It is fundamentally an order of magnitude lighter and cheaper than the technologies that are currently at play in those spaces. More importantly though, in areas that are outside of what conventional exoskeleton technologies can reach, consumer applications, light industrial applications, construction applications, conventional exoskeleton technologies cannot or have not proven that they can create a device cheap enough and functional enough to meet the needs in those spaces. And this order of magnitude drop in cost and weight really enables us to start reaching markets broader, as well as going after some old staples of exoskeleton.
Tim: ?
Tim Swift: Your goal is that you can – ultimately if you look at it you can think of this is just the actuator piece itself, right? And so if I look at this again, 20 psi and it is now a stiff structure right there. And so this is just fabric sewn together in a simple way, but then when it’s deflated you can see that once it deflates down it is just fabric, that’s all that’s in here, it feels like two pieces of fabric. So you can think of this easily being integrated into almost actuated clothing, you have almost like a compression pant or a compression shirt that you have or your actuation is directly built in and kind of creates a new paradigm for exoskeletons because it’s not one that we traditionally imagine when we think of Iron Man, things like that. So definitely not Iron Man.
Re:lololol (Score:4, Interesting)
Are you nuts? This is going to help my mom to walk. Screw military applications—if they can make this work, it will change the lives of a lot of people who have physical disabilities.
Theres a reason why pneumatic aren't used as much (Score:4, Interesting)
The big reason why pneumatics aren't used as much in robotics is that air is very compressible, which leads to all sorts of nastiness when you make pneumatic actuators.
Because air is compressible, compressing air is not very efficient compared to say hydraulics. This is bad for exoskeletons.
The other problem is that the compressibility of air limits the 'bandwidth,' or how fast these actuators can actuate and un-actuate controllably, achievable with these actuators. In addition, the bandwidth of pneumatic actuators is often below the frequency of human walking, making them impractical most exoskeleton applications.
And of course, there's more to it than compressibility at play here that could make these actuators impractical. Since these actuators use a rubber membrane, these actuators are subject to hysteresis, significant temperature effects, and creep.
Rubber, when stretched and unstretched quickly, heats up causing the rubber to change it's stiffness. In addition, the temperature of the rubber can also change due the air being pumped into them. Rubber, and other elastomers, also experiences a phenomenon known as creep, where it slowly stretches out with time. In fact, current industrial pneumatic muscles NEVER actuate exactly the same because of all this, and one has to use interesting control approaches.
I am also skeptical that this will be cheaper in practice than mass produced electric actuators. While the actuators themselves are cheap, the valves and other hardware necessary to control them are not. The actuators themselves will certainly wear out sooner than electric actuators(>10 years continuous operation for robot arm actuators) due to the creep mentioned above. With lower efficiency and increased maintenance costs the overall cost of using these could very well be higher.
In fact, the brushless motor in the compressor they show in the video probably can provide" 25% of the power of a normal human elbow," and the only reason it can't be used on a human elbow is that much of that power is at high-speed with low torque. If someone were to develop a compact and efficient gearbox for turning high speed- low torque into low speed-high torque, then one could mass produce it and skip all the pneumatic silliness.(Or just do what that company that robotics google just bought did and use watercooling/overclocking)
Re:Theres a reason why pneumatic aren't used as mu (Score:2, Interesting)
Pneumatics is way better exactly because air is compressible, that allows you to make something more akin to a controlled force actuator - making it easy to modulate force to pick up an egg or crush a brick. The actuators are also compliant, (inherently springy), meaning less precise positional control is required to do real world dynamic activities, and less energy will be required for things like walking/running. The control problem is mostly about modulating pressure quickly.
Rubber creep is obviously not a problem because the bladders are contained by a textile shell that doesn't creep. They provide an impermeable membrane to hold air in, not strength.
The big cost in conventional actuators is making an articulated structure that they can be attached to, and then all of the positional sensors and with tonnes of degrees of freedom that can accommodate a freely moving human body. If this can be built into suits then those costs and weights might be avoidable.
This approach would probably not make sense for industrial robotics or other precision applications. But exoskeleton/mobile robotics that have to interact with the real world could really benefit, particularly for exoskeletons where the human provides the fine control. Obviously a long way to go with development, but worth exploring.