YouSaid · the spoken record

Russ Tedrake

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172
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2020-08-09
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2020-08-09
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1
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  1. “The other thing I had going for me is actually that I wasn't a runner before and I learned to run after I had learned about barefoot running. I mean, started running longer distances. So I didn't have to unlearn. And I'm definitely, I'm a big fan of it for me, but I'm not going to, I tend to not try to convince other people. There's people who run beautifully with shoes on, and that's good. But here's why it makes sense for me. Um, It's all about the long term game, right? So I think it's just too easy to run 10 miles, feel pretty good, and then you get home at night and you realize my knees hurt. I did something wrong, right?”

    2020-08-09 · Lex Fridman Podcast · #114 – Russ Tedrake: Underactuated Robotics, Control, Dynamics and Touch · IDENTIFIED FROM THE TRANSCRIPT · source

  2. “Well, you know, it happened the other way, right? So I was studying walking robots and I was, there's a great conference called the Dynamic Walking Conference where it brings together both the biomechanics community and the walking robots community. And so I had been going to this for years and hearing talks by people who study barefoot running and other mechanics of running. So I did eventually read Born to Run. Most people read Born to Run in then, right?”

    2020-08-09 · Lex Fridman Podcast · #114 – Russ Tedrake: Underactuated Robotics, Control, Dynamics and Touch · IDENTIFIED FROM THE TRANSCRIPT · source

  3. “The most, I mean, the reason I spent a long time working on bipedal walking was because it was hard. And it challenged control theory in ways that I thought were important. Wouldn't have ever tried to convince you that you should start a company around bipeds or something like this. People that make pretty compelling arguments, right? I think the most compelling one is that the world is built for the human form. And if you want robots that work in the world we have today, then having a human form is a pretty good way to go. There are places that a biped can go that would be hard for other form factors to go, even natural places. At some point in the long run, we'll be building our environments for our robots, probably. And so maybe that argument falls aside.”

    2020-08-09 · Lex Fridman Podcast · #114 – Russ Tedrake: Underactuated Robotics, Control, Dynamics and Touch · IDENTIFIED FROM THE TRANSCRIPT · source

  4. “A great book, by the way, a series of books by Nicholas Caleb about fooled by randomness and black swan. Highly recommend them. But yeah, they make the point nicely that probably it was a few random events that, yeah, maybe it was someone getting hit by a rock, as you say.”

    2020-08-09 · Lex Fridman Podcast · #114 – Russ Tedrake: Underactuated Robotics, Control, Dynamics and Touch · IDENTIFIED FROM THE TRANSCRIPT · source

  5. “But probably the reason that one pre-Homo sapien species versus another survived was not because of whether they ate well when there was lots of food, but when the ice age came probably one of them happened to be in the wrong place. One of them happened to forage a food that was okay even when the glaciers came or something like that. There's a million variants.”

    2020-08-09 · Lex Fridman Podcast · #114 – Russ Tedrake: Underactuated Robotics, Control, Dynamics and Touch · IDENTIFIED FROM THE TRANSCRIPT · source

  6. “I mean, I think a lot of what dominated our evolution probably was not. The things that worked well sort of in the steady state When things are good, but For instance, people talk about what we should eat now because our ancestors were meat eaters or whatever”

    2020-08-09 · Lex Fridman Podcast · #114 – Russ Tedrake: Underactuated Robotics, Control, Dynamics and Touch · IDENTIFIED FROM THE TRANSCRIPT · source

  7. “Yeah, there are some great books written about the evolution of walking evolution of the human body. I think it's easy, though, to make. Bad evolutionary arguments.”

    2020-08-09 · Lex Fridman Podcast · #114 – Russ Tedrake: Underactuated Robotics, Control, Dynamics and Touch · IDENTIFIED FROM THE TRANSCRIPT · source

  8. “Think it's both, but I think we maybe have underestimated how important the dynamics are, right? I mean, even our bodies, the mechanics of our bodies, certainly with exercise, they evolve. So I actually lost a finger in early 2000s. And it's my fifth metacarpal. And it turns out you use that a lot in ways you don't expect when you're opening jars, even when I'm just walking around, if I bump it on something. There's a bone there that was used to taking contact. My fourth metacarpal wasn't used to taking contact. It used to hurt. It still does a little bit. But actually, my bone has remodeled, right? Over a couple years, the geometry, the mechanics of that bone changed to address the new circumstances. So the idea that somehow it's only our brain that's adapting or evolving is not right.”

    2020-08-09 · Lex Fridman Podcast · #114 – Russ Tedrake: Underactuated Robotics, Control, Dynamics and Touch · IDENTIFIED FROM THE TRANSCRIPT · source

  9. “I mean, I think part of the point is that we shouldn't draw a line as clearly as we tend to. But on a robot, we have motors and we have the links of the robot, let's say. If the motors are turned off, the robot has some passive dynamics. Gravity does the work. You can put springs. I would call that mechanics, right? If we have springs and dampers, which our muscles are springs and dampers and tendons. But then you have something that's doing active work, putting energy in, your motors on the robot. The controller's job is to send commands to the motor that add new energy into the system. So the mechanics and control interplay somewhere that divide is around, did you decide to send some commands to your motor or did you just leave the motors off, let them do their work?”

    2020-08-09 · Lex Fridman Podcast · #114 – Russ Tedrake: Underactuated Robotics, Control, Dynamics and Touch · IDENTIFIED FROM THE TRANSCRIPT · source

  10. “I mean, there are experiments that people do, careful experiments, that show that animals can adapt to unusual situations and recover efficiency. So there seems like, at least in one direction, I think there is reason to believe that the animal's motor system and probably its mechanics adapt in order to be more efficient. But efficiency isn't the only goal, of course. Sometimes it's too easy to think about only efficiency, but we have to do a lot of other things first, not get eaten, and then all other things being equal try to save energy.”

    2020-08-09 · Lex Fridman Podcast · #114 – Russ Tedrake: Underactuated Robotics, Control, Dynamics and Touch · IDENTIFIED FROM THE TRANSCRIPT · source

  11. “The dead fish basically starts swimming upstream, right? It's completely dead, no brain, no motors, no control, but somehow the mechanics of the fish resonate with the vortex street and it starts swimming upstream. It's one of the best examples ever.”

    2020-08-09 · Lex Fridman Podcast · #114 – Russ Tedrake: Underactuated Robotics, Control, Dynamics and Touch · IDENTIFIED FROM THE TRANSCRIPT · source

  12. “Put a string that went to tied the mouse of the fish to the rock so it couldn't go back and get caught in the grates. And then they asked what would that deadfish do when it was hanging out behind the rock? And so what you'd expect, it sort of flopped around like a dead fish in the vortex wake until something sort of amazing happens. And this video is worth putting in.”

    2020-08-09 · Lex Fridman Podcast · #114 – Russ Tedrake: Underactuated Robotics, Control, Dynamics and Touch · IDENTIFIED FROM THE TRANSCRIPT · source

  13. “Thing is that if you watch from above what the fish swims when it's not behind a rock, it has a particular gate. You can identify the fish the same way you look at a human walking down the street, you sort of have a sense of how human walks, the fish has a characteristic gate Put that fish behind the rock, its gate changes And what they saw was that it was actually resonating and kind of surfing between the vortices. Here was the experiment that really was the clincher because there was still it wasn't clear how much of that was mechanics of the fish, how much of that is control, the brain. So the clincher experiment, and maybe one of my favorites to date, although there are many good experiments. Took this was now a dead fish. They took a dead fish.”

    2020-08-09 · Lex Fridman Podcast · #114 – Russ Tedrake: Underactuated Robotics, Control, Dynamics and Touch · IDENTIFIED FROM THE TRANSCRIPT · source

  14. “Do you have a favorite example? It sort of goes with the passive walking idea. So is there, you know, how energy efficient are animals? There's a great series of experiments by George Lauder at Harvard and Mike Tranafilo at MIT. They were studying fish swimming in a water tunnel. And one of these, the type of fish they were studying were these rainbow trout because there was a phenomenon well understood that rainbow trout when they're swimming upstream at mating season They kind of hang out behind the rocks and it looks like, I mean, that's tiring work swimming upstream. They're hanging out behind the rocks. Maybe there's something energetically interesting there. So they tried to recreate that. They put in this water tunnel a rock, basically, a cylinder that had the same sort of vortex street. The eddies coming off the back of the rock that you would see in a stream. And they put a real fish behind this and watched how it swims. And the amazing”

    2020-08-09 · Lex Fridman Podcast · #114 – Russ Tedrake: Underactuated Robotics, Control, Dynamics and Touch · IDENTIFIED FROM THE TRANSCRIPT · source

  15. “Oh, I think everybody, even at the time, said that the answer is to do with that with control. But it was just pointing out that maybe the way we're doing control right now isn't the way we should.”

    2020-08-09 · Lex Fridman Podcast · #114 – Russ Tedrake: Underactuated Robotics, Control, Dynamics and Touch · IDENTIFIED FROM THE TRANSCRIPT · source

  16. “And you just have to give it a little bit of energy. This one only walked down a ramp. It would never walk on the flat to walk on the flat. You have to give a little energy at some point. Maybe instead of trying to take the forces imparted to you by the world and replacing them, what we should be doing is letting the world push us around and we go with the flow. Very Zen, very Zen robot.”

    2020-08-09 · Lex Fridman Podcast · #114 – Russ Tedrake: Underactuated Robotics, Control, Dynamics and Touch · IDENTIFIED FROM THE TRANSCRIPT · source

  17. “I think it gets a bad rap. Asimo is a beautiful machine. It does walk with its knees bent. Our Atlas walking had its knees bent. But actually, Asimo was pretty fantastic. But it wasn't energy efficient. Neither was Atlas when we worked on Atlas. None of our robots that have been that complicated have been very energy efficient. There's a thing that happens when you do control, when you try to control a system of that complexity. You try to use your motors to basically counteract gravity. Take whatever the world's doing to you and push back, erase the dynamics of the world, and impose the dynamics you want because you can make them simple and analyzable mathematically simple. And this was a very sort of beautiful example that you don't have to do that. You can just let go. Let physics do most of the work.”

    2020-08-09 · Lex Fridman Podcast · #114 – Russ Tedrake: Underactuated Robotics, Control, Dynamics and Touch · IDENTIFIED FROM THE TRANSCRIPT · source

  18. “This was in 97 when they first released it. It sort of announced P2 and then it went through, it was Asimo by then in 2004.”

    2020-08-09 · Lex Fridman Podcast · #114 – Russ Tedrake: Underactuated Robotics, Control, Dynamics and Touch · IDENTIFIED FROM THE TRANSCRIPT · source

  19. “It's on the boundary. I think there's a science to getting close to the solution. I think there's certainly art in the way that they made a beautiful robot. But then the finesse, because they were working with a system that wasn't perfectly modeled, wasn't perfectly controlled, there's all these little tricks that you have to tune the suction cups at the knees, for instance, so that they stick, but then they release at just the right time. Or there's all these little tricks of the trade. Really are art, but it was a point. I mean, it made the point we were at that time, the walking robot, the best walking robot in the world was Honda's Asimo. Absolutely marvel of modern engineering.”

    2020-08-09 · Lex Fridman Podcast · #114 – Russ Tedrake: Underactuated Robotics, Control, Dynamics and Touch · IDENTIFIED FROM THE TRANSCRIPT · source

  20. “What Steve and Andy and Ted McGear started the whole exercise, but what Steve and Andy did was they took it to this beautiful conclusion. They built something that had knees, arms, a torso, the arms swung naturally. Give it a little push, and that looked like a stroll through the park.”

    2020-08-09 · Lex Fridman Podcast · #114 – Russ Tedrake: Underactuated Robotics, Control, Dynamics and Touch · IDENTIFIED FROM THE TRANSCRIPT · source

  21. “You give that a push, it still wants to roll down the ramp. But every time it's foot, its spoke comes around and hits the ground, it loses a little energy Every time it takes a step forward, it gains a little energy. Things can come into perfect balance, and actually they want to. It's a stable phenomenon. If it's going too slow, it'll speed up. If it's going too fast, it'll slow down. And it comes into a stable periodic motion. Now you can take that rimless wheel, which doesn't look very much like a human walking. All the extra spokes away, put a hinge in the middle. Now it's two legs. That's called our compass gatewalker. That can still, you give it a little push, starts falling down a ramp, looks a little bit more like walking. At least it's a biped.”

    2020-08-09 · Lex Fridman Podcast · #114 – Russ Tedrake: Underactuated Robotics, Control, Dynamics and Touch · IDENTIFIED FROM THE TRANSCRIPT · source

  22. “Think the most beautiful motion of a robot has to be the passive dynamic walkers. I think there's just something fundamentally beautiful. The ones in particular that Steve Collins built with Andy Rowina at Cornell, a 3D walking machine. So it was not confined to a boom or a plane. That you put it on top of a small ramp, give it a little push. It's powered only by gravity. No controllers, no batteries whatsoever. It just falls down the ramp, and at the time it looked more natural and more graceful, more human like than any robot we'd seen to date, powered only by gravity. Well, okay, the simplest model is kind of like a slinky. It's like an elaborate slinky. One of the simplest models we used to think about it is actually a rimless wheel. So imagine taking a bicycle wheel, but take the rim off. So it's now just got a bunch of spokes.”

    2020-08-09 · Lex Fridman Podcast · #114 – Russ Tedrake: Underactuated Robotics, Control, Dynamics and Touch · IDENTIFIED FROM THE TRANSCRIPT · source