Russ Tedrake: Underactuated Robotics, Control, Dynamics and Touch | Lex Fridman Podcast #114

1. 0:00 – 4:29

   Introduction

   1. LFLex Fridman0:00

      The following is a conversation with Russ Tedrake, a roboticist and professor at MIT, and vice president of robotics research at Toyota Research Institute, or TRI. He works on control of robots in interesting, complicated, underactuated, stochastic, difficult to model situations. He's a great teacher and a great person. One of my favorites at MIT. We'll get into a lot of topics in this conversation, from his time leading MIT's DARPA Robotics Challenge Team, to the awesome fact that he often runs close to a marathon a day to and from work barefoot. For a world-class roboticist interested in elegant efficient control of underactuated dynamical systems like the human body, this fact makes Russ one of the most fascinating people I know. Quick summary of the ads. Three sponsors. Magic Spoon Cereal, BetterHelp, and Express VPN. Please consider supporting this podcast by going to magic spoon.com/lex and using code Lex at checkout, going to better help.com/lex and signing up at express vpn.com/lexpod. Click the links in the description, buy the stuff, get the discount. It really is the best way to support this podcast. If you enjoy this thing, subscribe on YouTube, review it with five stars on Apple Podcast, support it on Patreon, or connect with me on Twitter @lexfridman. As usual, I'll do a few minutes of ads now and never any ads in the middle that can break the flow of the conversation. This episode is supported by Magic Spoon, low-carb, keto-friendly cereal. I've been on a mix of keto/carnivore diet for a very long time now. That means eating very little carbs. I used to love cereal. Obviously most have crazy amounts of sugar, which is terrible for you, so I quit years ago. But Magic Spoon is a totally new thing. Zero sugar, 11 grams of protein, and only three net grams of carbs. It tastes delicious. It has a bunch of flavors. They're all good, but if you know what's good for you, you'll go with cocoa. My favorite flavor and the flavor of champions. Click the magic spoon.com/lex link in the description, use code Lex at checkout to get the discount and to let them know I sent you. So buy all of their cereal. It's delicious and good for you. You won't regret it. This show is also sponsored by Better Help, spelled H-E-L-P help. Check it out at better help.com/lex. They figure out what you need and match you with a licensed professional therapist in under 48 hours. It's not a crisis line, it's not self-help, it is professional counseling done securely online. As you may know, I'm a bit from the David Goggins line of creatures and so have some demons to contend with, usually on long runs or all-nighters full of self-doubt. I think suffering is essential for creation, but you can suffer beautifully in a way that doesn't destroy you. For most people, I think a good therapist can help in this, so it's at least worth a try. Check out the reviews. They're all good. It's easy, private, affordable, available worldwide. You can communicate by text anytime and schedule weekly audio and video sessions. Check it out at better help.com/lex. This show is also sponsored by Express VPN. Get it at express vpn.com/lexpod to get a discount and to support this podcast. Have you ever watched The Office? If you have, you probably know it's based on a UK series also called The Office. Not to stir up trouble, but I personally think the British version is actually more brilliant than the American one, but both are amazing. Anyway, there are actually nine other countries with their own version of The Office. You can get access to them with no geo restriction when you use Express VPN. It lets you control where you want sites to think you're located. You can choose from nearly 100 different countries, getting you access to content that isn't available in your region. So again, get it on any device at express vpn.com/lexpod to get an extra three months free and to support this podcast. And now here's my conversation with Russ Tedrake.

2. 4:29 – 9:40

   Passive dynamic walking

   1. LFLex Fridman4:29

      What is the most beautiful motion of a animal or robot that you've ever seen?

   2. RTRuss Tedrake4:36

      I 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 Ruina 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, more graceful, more human-like than any robot we'd seen to date. Powered only by gravity.

   3. LFLex Fridman5:15

      How does it work?

   4. RTRuss Tedrake5:17

      Well, okay, the simplest model, it's kind of like a Slinky. It's like an elaborate Slinky. Um, one of the simplest models we use to think about it is actually a rimless wheel. So imagine taking, uh, a bike- bicycle wheel, but take the rim off, so it's now just got a bunch of spokes. If you give that a push, it still wants to roll down the ramp, but every time its 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. Those things can come into perfect balance, and actually they, 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. Take all the extra spokes away, put a hinge in the middle, now it's two legs. That's, uh, called our compass gait walker. 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. But what Steve and Andy and, Tad McGeer started the whole exercise, but what Steve and Andy did was they took it to this beautiful conclusion where they built something that had knees, arms, a torso, the arms swung naturally, uh, give it a little push, and that looked like a stroll through the park.

   5. LFLex Fridman6:38

      How do you design something like that? I mean, is that art or science?

   6. RTRuss Tedrake6:42

      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, they made, they made a beautiful robot. But, um, but then the finesse, because, because this was work- 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 which really are art. But it was a point, I mean, it made the point. And we were, at, at that time, the walking robot, the best walking robot in the world was Honda's ASIMO. Absolutely marvel of modern engineering. It-

   7. LFLex Fridman7:24

      Is this '90s?

   8. RTRuss Tedrake7:25

      This was in '97 when they first released, it sort of announced P2 and then it went through, it was ASIMO by then in 2004, um...

   9. LFLex Fridman7:34

      (laughs) And it, it looks like this, uh, very cautious walking, like you're walking on, on hot coals or something like that.

   10. RTRuss Tedrake7:41

       It's, uh, uh, 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. Um, none of our robots have, that have been that complicated have been very energy efficient. But there was a, 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 s- sort of beautiful example that you don't have to do that. You can just let go. Let physics do most of the work, right? 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. But 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.

   11. LFLex Fridman9:01

       Yeah, but, okay, so that, that sounds very zen. But you can, I can also imagine how many, like, failed versions they had to go through. Like how many f- like I would say it's prob- would you say it's in the thousands that they've had to have the system fall down before they figured out how to get it?

   12. RTRuss Tedrake9:19

       I don't know if it's thousands, but, uh, it's a lot. It takes some patience. There's no question.

   13. LFLex Fridman9:25

       So in that sense, control might help a little bit.

   14. RTRuss Tedrake9:28

       Oh, the abs- 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

3. 9:40 – 13:34

   Animal movement

   1. RTRuss Tedrake9:40

      should.

   2. LFLex Fridman9:41

      Got it. So what about on the animal side? The ones that, uh, figured out how to move efficiently. Is there anything you find inspiring or beautiful in the movement of any particular animal?

   3. RTRuss Tedrake9:50

      I do have a favorite example.

   4. LFLex Fridman9:52

      Okay. (laughs)

   5. RTRuss Tedrake9:54

      So it sort of goes with the passive walking idea. So is there, you know, how, how energy efficient are animals? Okay, there's a great series of experiments by George Lauder at Harvard and Mike Tranquillo at MIT. They were studying fish swimming in a water tunnel.

   6. LFLex Fridman10:10

      Mm-hmm.

   7. RTRuss Tedrake10:10

      Okay? And one of these, the type of fish they were studying were these rainbow trout, because they, there was an phenomenon well-understood that rainbow trout, when they're swimming upstream at mating season, they kind of hang out behind the rocks. And 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 stream.

   8. LFLex Fridman10:40

      Mm-hmm.

   9. RTRuss Tedrake10:40

      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 thing is that if you watch from above, what the fish swims when it's not behind a rock, it has a particular gait. You can identify the fish the same way you look at a human looking th- walking down the street. You sort of have a sense of how a human walks. A fish has a characteristic gait. You put that fish behind the rock, its gait changes, and what y- they saw was that it was actually resonating and kind of s- surfing between the vortices.

   10. LFLex Fridman11:15

       Yeah.

   11. RTRuss Tedrake11:16

       Now here was the experiment that really was the clincher 'cause 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, they took, they, this was now a dead fish, um, they took a dead fish-

   12. LFLex Fridman11:40

       (laughs)

   13. RTRuss Tedrake11:40

       They put a string that went, that tied the mouth of the fish to the rock, so it couldn't go back and get caught in the grates. Uh, and then they asked, "What would that dead fish 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, in the vortex wake, until something sort of amazing happens. And this video is worth putting in.

   14. LFLex Fridman12:01

       (laughs) Yeah.

   15. RTRuss Tedrake12:02

       Right?

   16. LFLex Fridman12:02

       What happens?

   17. RTRuss Tedrake12:03

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

   18. LFLex Fridman12:20

       What, who do you credit for that too? Is that just evolution constantly just figuring out by killing a lot of generations of animals, uh, like, the most efficient motion? Is that, uh, or maybe the physics of our world completely, like... It's like if evolution applied not only to animals, but just the entirety of it somehow drives the efficiency. Like, nature likes efficiency. I don't know if that question even makes any sense.

   19. RTRuss Tedrake12:50

       I understand the question. That's re- I mean, (laughs) do they co-evolve? Um-

   20. LFLex Fridman12:54

       Yeah, somehow co- yeah, like, I, I don't know if an environment can evolve but, um...

   21. RTRuss Tedrake13:00

       I mean, there are experiments that people do, careful experiments that show that, um, 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, um, and probably its mechanics, uh, adapt in order to be more efficient. But efficiency isn't the only goal, of course. Um, 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.

4. 13:34 – 15:49

   Control vs Dynamics

   1. RTRuss Tedrake13:34

   2. LFLex Fridman13:34

      By the way, let's, uh, draw a distinction between control and mechanics. Like, how, how can, how would you define each?

   3. RTRuss Tedrake13:40

      Yeah. I mean, I, I think part of the point is that we shouldn't draw a line-

   4. LFLex Fridman13:45

      Right.

   5. RTRuss Tedrake13:45

      ... as, as, as clearly as we tend to. But the, you know, 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, okay? 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, um, but then you have something that's doing active work, putting energy in, which are your motors on the robot. The controller's job is to send commands to the motor that add new energy into the system, right? So, the mechanics and control interplay, somewhere the divide is around, you know, did you decide to, uh, send some commands to your motor or did you just leave the motors off and let them do their work?

   6. LFLex Fridman14:30

      Uh, would you say, is most, most of nature on the, uh, dynamic side or the control side? So like, if you look at biological systems or f- you know, we're living in a pandemic now, like, do you think a virus is a... (laughs) do you think is a dynamic system or, um, or is there a lot of control, intelligence?

   7. RTRuss Tedrake14:54

      I think it's both, but I think we maybe have underestimated how important the dynamics are, right? Um, I mean, even our bodies, the mechanics of our bodies, certainly with exercise, they evolve, but... Uh, so I actually, I lost a finger in early 2000s, and, um, it's my fifth metacarpal. And it turns out you use that a lot, um, 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, uh, 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?

   8. LFLex Fridman15:33

      Mm-hmm.

   9. RTRuss Tedrake15:34

      The, the, over the la- 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, is not right.

5. 15:49 – 20:56

   Bipedal walking

   1. RTRuss Tedrake15:49

   2. LFLex Fridman15:50

      Maybe sticking on evolution for a bit, 'cause, um, it's tended to create some interesting things, uh, bipedal walking, do you, um... Why the heck did evolution give us... I think we're, are we the only mammals that walk on two feet?

   3. RTRuss Tedrake16:06

      No. I mean, there's a bunch of animals that do it a bit.

   4. LFLex Fridman16:10

      A bit.

   5. RTRuss Tedrake16:10

      There's a, there, I think we are the most successful bipeds.

   6. LFLex Fridman16:13

      I, I think some, uh, I think I read somewhere that, um, the reason the, you know, evolution made us walk on two feet is because, uh, there's an advantage to being able to carry food back to the tribe or something like that, so like you can carry, it's kind of this communal, uh, cooperative thing, so like to carry stuff back to, um, to a place of shelter and so on to share with others. Um, do you understand at all the value of, uh, walking on two feet from a, both a robotics and a human perspective?

   7. RTRuss Tedrake16:49

      Yeah. There are some great books written about evolution of walking, evolution of the human body. I think it's easy though to make bad evolutionary arguments.

   8. LFLex Fridman17:00

      Sure. (laughs)

   9. RTRuss Tedrake17:02

      Um...

   10. LFLex Fridman17:02

       Most of them are probably bad, but what, what else can we do?

   11. RTRuss Tedrake17:06

       I mean, I think, um, a lot of what dominated our evolution probably was not the things that worked well sort of in the steady state, um, uh, you know, when things are, when things are good, but, but, uh, for instance, people talk about what we should eat now because our ancestors were meat eaters or, or whatever.

   12. LFLex Fridman17:28

       Oh, yeah, I love that. Yeah.

   13. RTRuss Tedrake17:30

       But probably, you know, the reason that one pre-, uh, pre-Homo sapiens species versus another survived was not because of whether they ate well, uh, when there was lots of food, but when the Ice Age came, you know, probably one of them happened to be in the wrong place, one of them happened to, uh, forage a food that was okay even, even when the, the glaciers came or something like that. I mean, the point is-

   14. LFLex Fridman17:58

       There's a million variables that contributed and we can't... And our, actually the amount of information we're working with in telling these stories, uh, these evolutionary stories is, um, is very little. So just, yeah, just like you said, it, it seems like if we, if we study history, it seems like history turns on like these little events...... that, um, that otherwise would seem meaningless. But in, in a grand, like when you, in retrospect, were, um, turning points.

   15. RTRuss Tedrake18:27

       Absolutely.

   16. LFLex Fridman18:28

       And that, that's probably how, like somebody got hit in the head with a rock because somebody slept with the wrong person back in the (laughs) K days, and somebody get, uh, get angry and that turned, uh, you know, warring tribes, com- combined with the environment, all those millions of things, and the meat-eating. Which I get a lot of criticism because I, I don't know, um, I don't know what your dietary processes are like, but these days I been eating only meat, which is, um ... There's, there's a large community of people who say, yeah, probably make evolutionary arguments and say, "You do a great job." There's probably an even larger community of people, including my mom, who says it's, uh, deeply unhealthy, it's wrong, but I just feel good doing it. But, you're right, I, uh, these evolutionary arguments can be flawed. But is there anything interesting to pull out for, um, for walking?

   17. RTRuss Tedrake19:17

       There's a great book, by the way, um, well a series of books by Nicholas Taylor about Fooled by Randomness and Black Swan. Um, highly recommend them, but yeah, they make the point nicely that probably it was a few random events that, yes, maybe it was, uh, someone getting hit by a rock as you say.

   18. LFLex Fridman19:38

       Uh, that said, do you think, uh, I don't know how to ask this question or how to talk about this, but there's something elegant and beautiful about moving on two feet. Obviously biased because I'm human, but, uh, from a robotics perspective too, you work with robots on two feet, is it, um, is it at all useful to build robots that are on two feet as opposed to four? Is there something useful about it?

   19. RTRuss Tedrake20:02

       I think the most, um, I mean the reason I spent a long time working on wa- bipedal walking was because it was hard, and it was, um, it challenged control theory in ways that I thought were important. Um, I wouldn't have ever tried to convince you that, um, you should start a company around bipeds or something like this. There are 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 a robot to work in the world we have today, then, you know, having a human form is a pretty good way to go. Um, there are, there are places that a biped can go that would be hard for, uh, other form factors to go, even natural places. But, um, you know, at some point in the long run, we'll be building our environments for our robots probably, and so maybe that argument falls aside.

6. 20:56 – 33:01

   Running barefoot

   1. LFLex Fridman20:56

      So, you famously run barefoot. Uh, do you still run barefoot?

   2. RTRuss Tedrake21:02

      I still run barefoot.

   3. LFLex Fridman21:03

      That's so awesome.

   4. RTRuss Tedrake21:04

      Much to my wife's chagrin. (laughs)

   5. LFLex Fridman21:07

      (laughs) Do you wanna make an evolutionary argument for why running barefoot (laughs) is advantageous? Um, (laughs) , what have you learned about, um, human and robot movement in general from running barefoot? Human or robot, and/or?

   6. RTRuss Tedrake21:23

      Well, you know, it happened the other way, right? So, I was studying walking robots and, uh, I was ... There's a great conference called the Dynamic Walking Conference, uh, 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, the mechanics of running. So I, I did eventually read Born to Run. Most people read Born to Run and then-

   7. LFLex Fridman21:51

      First then.

   8. RTRuss Tedrake21:52

      ... read ... Right? Um, the other thing I had going for me is actually that I, um, I wasn't, I wasn't a runner before, and I learned to run after I had learned about barefoot running, or I mean, started running longer distances. So I didn't have to unlearn. And I'm definitely, um, I'm a big fan of it for me, but I'm not gonna ... I tend to not try to convince other people. There's people who run beautifully with shoes on (laughs) , and that's good. Um, but here's why it makes sense for me. Um, it's all about the long-term game, right? So I, I think it's just too easy to run 10 miles, feel pretty good, and then you get home at night and you realize, uh, "My knees hurt. I did something wrong." Right? Um, if you take your shoes off, then if, if you hit hard with your foot at all, um, then it hurts. (laughs) You don't like run 10 miles, uh, and then, and then realize you've done something, some damage. You have immediate feedback-

   9. LFLex Fridman22:52

      Mm-hmm.

   10. RTRuss Tedrake22:52

       ... telling you that you've done something that's, that's maybe suboptimal, and you change your gait. I mean, it's even subconscious. If I, right now, having run many miles barefoot, if I put a shoe on, my gait changes in a way that I think is not as good. Um, so, so it, it makes me land softer, and I think my, my goals for running are to do it for as long as I can into old age, um, not to win any races. And so for me, this is a, uh, you know, a way to protect myself.

   11. LFLex Fridman23:23

       Yeah, I think, um, first of all, I've tried running barefoot (laughs) many years ago, uh, probably the other way, just, just, just, uh, reading Born to Run, but just to understand because I felt like I couldn't put in the miles that I wanted to, uh, and it feels like, um ... Running for me, and I think for a lot of people, was one of those activities that we do often and we never really try to learn to do correctly. (laughs) Like, it's funny, there's so many activities we do every day, like brushing our teeth, right? Uh, I think a lot of us, at least me, probably have never deeply studied how to properly brush my teeth, right? Or wash, as now with the pandemic, or how to properly wash our hands. We do it every day, but we haven't really studied, like, "Am I doing this correctly?" But running felt like one of those things that it was absurd not to study how to do correctly 'cause it's the source of so much pain and suffering. Like, I hate running, but I do it (laughs) - (laughs)

   12. RTRuss Tedrake24:25

       ... I do it because I hate it, but it- I- I feel good afterwards. But I think it feels like you need to learn how to do it properly. So, that's where barefoot running came in, and then I quickly realized that my gait was completely wrong. I was taking huge, like, steps and, um, landing hard on the heel, all those elements. And so, yeah, from that I actually learned to take really small steps. Look, uh, I already forgot the number, but I feel like it was 180 a minute or something like that. And I- I remember I was, uh, I actually just took songs that are 180 beats per minute and then, like, tried to run at that beat, uh, just to teach myself. It took, it took a long time and I feel like, uh, after a while you, you learn to, to run, you adjust it properly without going all the way to barefoot. But I feel like barefoot is the legit way to do it. I, I mean, I think a lot of people would be really curious about it. Can you, if they're interested in trying, what would you ... how would you recommend they start or try or explore? Slowly. (laughs)

   13. LFLex Fridman25:32

       (laughs)

   14. RTRuss Tedrake25:32

       That's the biggest thing people do is they are excellent runners and they're used to running long distances or running fast and they take their shoes off and they hurt themselves instantly trying to do something that they were used to doing. I, I think I lucked out in the sense that I, I couldn't run very far when I first started trying. And I run with minimal shoes too. I mean, I will, uh, you know, bring along a pair of actually, like, aqua socks or something like this I can just slip on, or running sandals. I've tried all of them.

   15. LFLex Fridman26:00

       What's the difference between a minimal shoe and nothing at all? What's, like feeling-wise, what does it feel like?

   16. RTRuss Tedrake26:07

       There is a ... I mean, I, I noticed my gait changing, right? So, um, I mean, your, your foot has as many muscles and sensors as your hand does, right?

   17. LFLex Fridman26:17

       Sensors. Ooh, okay.

   18. RTRuss Tedrake26:20

       And, uh, we do amazing things with our hands, and we stick our foot in a big solid shoe, right? So there's, I think, you know, when you're barefoot, you're l- you're just giving yourself more proprioception, and that's why you're more aware of some of the gait flaws and stuff like this. Now, you have less protection too. So, um-

   19. LFLex Fridman26:40

       Rocks and stuff. That-

   20. RTRuss Tedrake26:42

       I mean, yeah. So, so I think people are, who are afraid of barefoot running, they're worried about getting cuts or getting, stepping on rocks. Um, first of all, even if that was a concern, I think those are all, like, uh, very short term. You know, if I get a scratch or something, it'll heal in a week. If I blow out my knees, I'm done running forever. So I will trade the short term for the long term anytime. But even then, (laughs) you know, uh, and this, again, to my wife's chagrin, um, your feet get tough, right? And, uh, uh-

   21. LFLex Fridman27:08

       A callous. Okay.

   22. RTRuss Tedrake27:09

       Yeah. I can run over almost anything now. (laughs)

   23. LFLex Fridman27:13

       (laughs) I mean, what, um ... Maybe c- can you talk about is there hint, like is there tips or tricks that you have, uh, suggestions about ... Like if I wanted to try it.

   24. RTRuss Tedrake27:26

       You know, there, there is a good book actually. Uh, there's probably more good books since I read them. But, uh, Ken Bob, Barefoot Ken Bob Saxton.

   25. LFLex Fridman27:35

       Mm-hmm. (laughs)

   26. RTRuss Tedrake27:37

       Um, he's an interesting guy, but I think his book captured, uh, the right way to describe running, barefoot running to somebody better than any other I've seen.

   27. LFLex Fridman27:48

       So, you run pretty good distances and you bike. And is, is there, um, you know, if we talk about bucket list items, i- is there something crazy on your bucket list athletically that you hope to do one day?

   28. RTRuss Tedrake28:04

       I mean, my commute is already a little crazy. Um-

   29. LFLex Fridman28:07

       What are we talking about here? What, what, uh, what distance are we talking about?

   30. RTRuss Tedrake28:11

       Well, I live about 12 miles from MIT, but you can find lots of different ways to get there. So, I mean, I've run there for a long, many years. I've biked there. Um-
7. 33:01 – 44:05

   Think rigorously with machine learning

   1. RTRuss Tedrake33:02

   2. LFLex Fridman33:02

      Let's go into robotics a little bit. What, to you, is the most beautiful idea in robotics? Whether we're talking about control, or whether we're talking about optimization and the math side of things, or the engineering side of things, or the philosophical side of things.

   3. RTRuss Tedrake33:18

      Mm-hmm. I think I've been lucky to experience something that not so many roboticists have experienced, which is to hang out with some really amazing control theorists (laughs) and, um, the clarity of thought that some of the more mathematical control theory can bring to even very complex, messy-looking problems is really, it really had a big impact on me, and, and, uh, I had a day even ac-, just a couple weeks ago where I'd spent the day on a Zoom robotics conference having great conversations with lots of people, felt really good, um, about the ideas that were flowing and, and the like. And then I had a, you know, late afternoon meeting with, uh, one of my favorite control theorists, and, um, and we went from these, from these abstract discussions about maybes and what-ifs and, and what a great idea, to these super precise statements about systems that aren't that much f- more simple or, or abstract than the ones I care about deeply. And the contrast of that is, um ... I don't know, it, it really gets me. I think people underestimate, um, maybe the power of clear thinking. Uh, uh, and so for instance, deep learning is amazing. Um, I use it heavily in our work. I think it's changed the world, unquestionable. It makes it easy to get things to work without thinking as critically about it. So I think one of the challenges as an educator is to think about, um, how do we make sure people get a taste of the more rigorous thinking that I think goes along, uh, with, with some different approaches.

   4. LFLex Fridman35:24

      Yeah, so that's really interesting. So, understanding, like, the fundamentals, the first principles of the, of the, the, the pro-, the problem, or in this case, it's mechanics. It's, like, how a thing moves, how a thing behaves, like, all the forces involved, like, really getting a deep understanding of that. I mean, it, the, from physics, the first principle thing come from physics, and here it's literally physics. Uh, yeah, and this applies, in deep learning, this applies to, um, not just, I mean, it applies so cleanly in, in robotics, but it also applies to just in any data set. I find this true, I mean, driving as well. There's a lot of folks in the t-, uh, that work on autonomous vehicles that don't study driving (laughs) like, deeply. I, I, I might be coming a little bit from the psychology side, but, um, I remember I spent a ridiculous number of hours o- at lunch-... a, (laughs) a- a- this, like, lawn chair, and I would sit somewhere, um, somewhere on MIT's campus, there's a few interesting intersections, and we'd just watch people cross. So we were studying, um, uh, pedestrian behavior, and I felt like... And to record a lot of video, to try it, and then there's the computer vision extracts their movement, how they move their head, and so on. But, like, every time, I felt like I didn't understand enough. I, I just, I, I felt like I wasn't understanding what, how are people signaling to each other? What are they thinking? How cognizant are they of their fear of death? (laughs) Like, what are we, like, what's the game th- what's the underlying game theory here? What are, what are the, the, the incentives? And then I finally found a livestream, uh, of an intersection that's, like, high def that I just, I would watch so I wouldn't have to sit out there. But that's interesting, so, like, I feel, I get-

   5. RTRuss Tedrake37:23

      But that's tough. That's a tough example because, I mean, the learning-

   6. LFLex Fridman37:27

      Humans are involved. (laughs)

   7. RTRuss Tedrake37:28

      Not just because human, but I, I think, um, the learning mantra is the basically the statistics of the data will tell me things I need to know, right? And, uh, you know, for the example you gave of all the nuances of, um, you know, eye contact, or hand gestures, or whatever that are happening for these subtle interactions between pedestrians and traffic, right? Maybe the data will tell this- tell- tell that story. Uh, maybe even, I, I, uh, one level more meta (laughs) than, than what you're saying. Um, for a particular problem, I think it might be the case that data should tell us the story. But I think there's a rigorous thinking that is just an essential skill for a mathematician or an engineer that, um, I just don't wanna lose it.

   8. LFLex Fridman38:18

      Yes.

   9. RTRuss Tedrake38:18

      There are, there are certainly super rigorous, um, rigorous control, or sorry, um, machine learning people. I just think deep learning makes it so easy-

   10. LFLex Fridman38:27

       Right.

   11. RTRuss Tedrake38:28

       ... to do some things that, um, our next generation are, um, not immediately rewarded for going through some of the more rigorous approaches, and then I wonder where that takes us. I j- well, I'm, I'm actually optimistic about it. I just want to, um, do my part to try to steer that rigorous thinking.

   12. LFLex Fridman38:48

       So, there's, like, two questions I wanna ask. D- do you have sort of a, a good example of rigorous thinking where it's easy to get lazy and not do the rigorous thinking? And the other question I have is, like, do you have advice of, um, how to practice rigorous thinking in, um, in, uh, in all the, uh, computer science disciplines that we've mentioned?

   13. RTRuss Tedrake39:16

       Yeah, I mean, uh, there are times where problems that can be solved with well-known mature methods, um, could also be solved with, uh, with a deep learning approach. And, um, there's an argument that you must use learning even for the parts we already think we know because if the human has touched it, then you've, you've, d- you've biased the system and you've su- suddenly put a bottleneck in there that, uh, is your own mental model. But something like inverting a matrix, you know, I, I think we know how to do that pretty well, even if it's a pretty big matrix, and we understand that pretty well. And you could train a deep network to do it, but you shouldn't, probably.

   14. LFLex Fridman39:57

       So r- so in that sense, rigorous thinking is, uh, understanding the, the scope and the limitations of the meth- of the methods that we have. Like, how to use the tools of mathematics properly?

   15. RTRuss Tedrake40:10

       Yeah. I think, you know, uh, i- taking a class on analysis is all I'm still, or sort of-

   16. LFLex Fridman40:16

       Right.

   17. RTRuss Tedrake40:16

       ... arguing is to take, take a chance to stop and, and force yourself to think rigorously about even, you know, the rational numbers or something, you know, it doesn't have to be the end-all problem. But that exercise of clear thinking, I think, uh, goes a long way, and I just wanna make sure we, we keep preaching it.

   18. LFLex Fridman40:35

       We don't lose it.

   19. RTRuss Tedrake40:36

       Yeah.

   20. LFLex Fridman40:36

       But do you think, uh, when you're doing, like, rigorous thinking or, like, maybe, uh, trying to write down equations or sort of explicitly, like, formally describe a system, do you think we naturally simplify things too much? Is that a danger you run into? Like, uh, in order to be able to understand something about the system mathematically, we, uh, make it too much of a toy example?

   21. RTRuss Tedrake41:01

       But I think that's the good stuff, right? Um...

   22. LFLex Fridman41:04

       That's how you understand the fundamentals?

   23. RTRuss Tedrake41:07

       I think so. I think, uh, uh, maybe even that's a key to intelligence or something. But, I mean, if, okay, what if Newton and Galileo had deep learning?

   24. LFLex Fridman41:15

       (laughs)

   25. RTRuss Tedrake41:15

       And, and, and they had done a bunch of experiments and they told the world, "Here's your weights-

   26. LFLex Fridman41:21

       Yes.

   27. RTRuss Tedrake41:21

       ... of your neural network. I've, we've solved the problem."

   28. LFLex Fridman41:23

       Yeah.

   29. RTRuss Tedrake41:24

       You know, where would we be today? I don't, I don't think we'd be as far as we, as we are. There's something to be said about having a, the simplest explanation for a phenomenon. So I don't doubt that we can train neural networks to predict even physical, um, you know, uh, F equals MA type equations. But, um, I maybe I, I want another Newton to come along 'cause I think there's more to do in terms of coming up with the simple models for more complicated tasks.

   30. LFLex Fridman41:59

       Yeah. Uh, let's not offend the AI systems from 50 years from now that are listening to this that are probably better at, might be better coming up with F equals MA equations themselves. So-
8. 44:05 – 1:07:14

   DARPA Robotics Challenge

   1. LFLex Fridman44:05

      First of all, I mean, I'll probably do it in the introduction, but you're, uh, one of the great robotics people at MIT. You're a professor at MIT. You've... Teach in a lot of amazing courses. You run a large group. Uh, and you have a important history for MIT, I think, as, uh, being a part of the DARPA Robotics Challenge. Can you maybe first say what is the DARPA Robotics Challenge and then tell your story around it, your journey with it?

   2. RTRuss Tedrake44:36

      Yeah, sure. Um, so the DARPA Robotics Challenge, it came on the tails of the DARPA Grand Challenge and DARPA Urban Challenge, which were the challenges that brought us... um, put a spotlight on self-driving cars. Um, Gill Pratt was at DARPA and pitched a new challenge that involved disaster response. Um, it didn't explicitly require humanoids, although humanoids came into the picture. This happened shortly after the Fukushima disaster in Japan, and our challenge was motivated roughly by that because that was a case where if we had had robots that were ready to be sent in, there's a chance that we could have, um, averted a disaster. And certainly, after the, um... in the disaster response, there were times where we'd love- we would have loved to have sent robots in. So in practice, what we ended up with was a- a grand challenge, uh, DARPA Robotics Challenge, um, where Boston Dynamics was, uh, was to make humanoid robots. People like me and the- the amazing team at MIT, um, were competing first in a simulation challenge to try to be one of the ones that wins the right to work on one of the, uh, the Boston Dynamics humanoids in order to compete in the- the final challenge, which was a physical challenge.

   3. LFLex Fridman46:08

      And at that point, it was already... So it was decided as humanoid robots early on?

   4. RTRuss Tedrake46:13

      So there were... There were two tracks. There w- you could enter as a hardware team where you brought your own robot, or you could enter through the virtual robotics challenge as a software team that would try to win the right to use one of the Boston Dynamics robots.

   5. LFLex Fridman46:25

      Which are called Atlas-

   6. RTRuss Tedrake46:27

      Atlas.

   7. LFLex Fridman46:27

      ... humanoid robots.

   8. RTRuss Tedrake46:28

      Yeah.

   9. LFLex Fridman46:28

      Yeah.

   10. RTRuss Tedrake46:28

       It was a 400-pound marvel, but, uh, you know, pretty big, scary-looking robot.

   11. LFLex Fridman46:35

       Expensive, too-

   12. RTRuss Tedrake46:36

       Expensive, yeah.

   13. LFLex Fridman46:36

       ... at least at the time. Yeah.

   14. RTRuss Tedrake46:37

       Mm-hmm.

   15. LFLex Fridman46:38

       Okay, so, um, I mean, how did you feel at the prospect of this kind of challenge? I mean, it seems... You know, autonomous vehicles, yeah, I guess that sounds hard, but, uh, not really from a robotics perspective. It's like, "Didn't they do it in the '80s?" is the kind of feeling I would have. (laughs) Uh, like when you first look at the problem, it's on wheels, but, like, humanoid robots, that sounds really hard. Uh, so what... Like, how, what- what are the, psychologically speaking, what were you feeling? Excited? Scared? Why the heck did you get yourself involved in this kind of messy challenge?

   16. RTRuss Tedrake47:19

       We didn't really know for sure what we were signing up for.

   17. LFLex Fridman47:23

       Of course.

   18. RTRuss Tedrake47:24

       Um, in the sense that you could have something that, as it was described in the call for participation, um, that could have put a huge emphasis on the dynamics of walking and not falling down and walking over rough terrain or the same description, 'cause the robot had to go into this disaster area and turn valves and- and, uh, pick up a drill or cut a hole through a wall. It had to do some interesting things. The challenge could have really highlighted perception and autonomous planning, or it- it ended up that, you know, locomoting over a complex, uh, terrain played a pretty big role in the competition. So, um-

   19. LFLex Fridman48:05

       And the degree of autonomy wasn't clear.

   20. RTRuss Tedrake48:08

       The degree of autonomy was always a central part of the discussion. So, um, what wasn't clear was how we would be able... how far we'd be able to get with it. So the idea was always, uh, that you want semi-autonomy, that you want the robot to have enough compute that you can have a degraded network link to a human. And so the same way you... we had degraded networks at a- at a many natural disasters, you'd send your robot in.... you'd be able to get a few bits back and forth, but you don't get to have enough, potentially, to fully, uh, operate the robot, every joint of the robot. So, and then the question was, and the gamesmanship of the organizers was to figure out what we're capable of, push us as far as we could, so that, um, it would differentiate the teams that put more autonomy on the robot and had a few clicks and just said, "Go there, do this. Go there, do this," versus someone who's picking every footstep or something like that.

   21. LFLex Fridman49:05

       So, what were some, uh, memories, painful, triumphant from the experience? Like, what was that journey? Maybe c- if you can dig in a little deeper, maybe even on the technical side, on the team side, that, that whole process of, um, from the e- early idea stages to actually competing to find the stage.

   22. RTRuss Tedrake49:28

       I mean, this was a defining experience for me. I, I, it came at the right time for me in my career. I had gotten tenure before I was due a sabbatical (laughs) and most people do something, you know, relaxing and restorative for a sabbatical.

   23. LFLex Fridman49:41

       So, you got tenure before the, the, before this?

   24. RTRuss Tedrake49:44

       Yeah. Yeah, yeah. It was a good time for me. I had, I had, we had a bunch of algorithms that we were very happy with. We wanted to see how far we could push them, and this was a chance to really test our mettle, to do more proper software engineering. Um, the team, we all just worked our butts off. We, you know, were in that lab almost all the time. Um, okay, so there, I mean, there were some, of course, high highs and low lows throughout that, uh, anytime you're, you know, not sleeping and devoting your life to a 400-pound humanoid. Um, I r- I remember actually one funny moment where we're all super tired, and so Atlas had to walk across cinder blocks. That was one of the obstacles. And I remember Atlas was powered down and hanging limp, you know, on the, on its harness. And the, the humans were there, like, laying, you know, picking up and laying the brick down so that the robot could walk over it, and I thought, "What is wrong with this?" (laughs) You know?

   25. LFLex Fridman50:38

       (laughs)

   26. RTRuss Tedrake50:40

       We got, we've got a robot just watching us do all the manual labor so that it can take its little, um-

   27. LFLex Fridman50:44

       (laughs)

   28. RTRuss Tedrake50:45

       ... stroll across the terrain.

   29. LFLex Fridman50:46

       Yeah.

   30. RTRuss Tedrake50:47

       But, uh...
9. 1:07:14 – 1:18:32

   When will a robot become UFC champion

   1. LFLex Fridman1:07:15

      Now you're a serious person. (laughs) Um, I'm a little bit of an idiot and I'm going to ask you some dumb questions. Uh, so I do, uh, I do martial arts, uh, so like jiujitsu. There's cr- I've wrestled my whole life. So let me, (laughs) let me ask the question, um, you know, like whenever people learn that I do any kind of AI or, like I mention robots and things like that, they say, "When are we gonna have robots that, um, you know, that can win in a wrestling match or in a fight against a human?" Uh, so we just mentioned sitting on your butt, feet in the air. That's a common position in jiujitsu when you're on the ground, you're, uh, when you're, you're an down opponent. Um, like what, how difficult do you think is the problem and when will we have a robot that can defeat a human in a wrestling match?

   2. RTRuss Tedrake1:08:07

      Mm-hmm.

   3. LFLex Fridman1:08:08

      And we're talking about a lot, like if, I don't know if you're familiar with wrestling, but es- essentially, um-

   4. RTRuss Tedrake1:08:15

      Not very.

   5. LFLex Fridman1:08:16

      ... it's basically the art of contact. It's like, it's, 'cause you're, you're, you're, you're picking contact points and then using, like, leverage, like to, uh, off-balance, to, to trick people. Like, you, uh, make them feel like you're doing one thing, and then they s- they change their balance, and then you, uh, switch what you're doing, and then it results in a throw or whatever. So, like, it's basically the art of multiple contacts. So-

   6. RTRuss Tedrake1:08:48

      Awesome. That's a nice description of it. So there's also an opponent in there, right? So, so if-

   7. LFLex Fridman1:08:54

      Very dynamic.

   8. RTRuss Tedrake1:08:55

      ... right? If you are wrestling a human and, um, are in a game theoretic situation with a human, that's still hard. Uh, but just to speak to the, you know, quickly reasoning about contact part of it, for instance.

   9. LFLex Fridman1:09:11

      Yeah, maybe even throwing the game theory out of it.

   10. RTRuss Tedrake1:09:13

       Right.

   11. LFLex Fridman1:09:13

       Almost like a, yeah, almost like a non-dynamic opponent.

   12. RTRuss Tedrake1:09:17

       Right. There's reasons to be optimistic, but I think our best understanding of those problems are still pretty hard. Um, I have been increasingly focused on manipulation, partly where that's a case where the contact has to be much more rich. Um, and there are some really impressive examples of, of deep learning policies, controllers that, um, that can appear to do good things through contact. We've even got new examples of, of, you know, deep learning models of predicting what's gonna happen to objects as they go through contact. But I think the challenge you just offered there still eludes us, right? The, the ability to make a decision based on those models quickly, um, you know, I have to think though, it's hard for humans too when you get that complicated. I think probably you had maybe a slow motion version of where you learned the basic skills and you've probably gotten better at it and, and, um, there's, there's much more subtlety, but it might still be hard to actually, you know, really on the fly, take a, you know, model of your humanoid and figure out how to, how to plan the optimal sequence. That might be a problem we never solve.

   13. LFLex Fridman1:10:36

       Well, the repeti- the, I mean, one of the most amazing things to me about the, we, we, we can talk about martial arts, uh, we could also talk about dancing. It doesn't really matter. To human, um, I think it's the most interesting study of contact. It's not even the dynamic element of it. It's the, like, when you get good at it, it's so effortless. Like, I can just, I'm very cognizant of the entirety of the learning process being essentially, like, learning how to move my body in a way that I could throw very large weights around effortlessly. Like, and, and I can feel the learning. Like, I'm a huge believer in drilling of techniques. And you can just, like, feel your, I don't, you're not feeling, you're, you're feeling, um, sorry, you're learning it intellectually a little bit, but a lot of it is the body learning it somehow, uh, like instinctually. And wha- whatever that learning is, that's really... I'm not even sure if that's, um, equivalent to a, like, a deep learning, learning a controller. I think it's something more, it feels like there's a lot of distributed learning going on. (laughs)

   14. RTRuss Tedrake1:11:51

       Yeah, I think there's hierarchy and composition-

   15. LFLex Fridman1:11:54

       Yeah.

   16. RTRuss Tedrake1:11:54

       ... um, probably in the systems that we don't capture very well yet. Uh, you, you have layers of control systems. You have reflexes at the bottom layer, and you have a, you know, a system that's capable of, you know, planning a vacation to some distant country, which is probably, you probably don't have a controller or a policy for every possible destination you'll ever pick. Right? Um, but there's something magical in the in between and how do you go from these low-level feedback loops to something that feels like a pretty complex set of outcomes. You know, my guess is, I think, I think there's evidence that you can plan at some of these levels, right? So, uh, Josh Tenenbaum just showed it, uh, in his talk the other day. He's got a game he likes to talk about it. I think he calls it the pick three game or something.... where he puts a bunch of clutter down in front of, uh, a person and he says, "Okay. Pick three objects." And it might be a telephone or a shoe or a Kleenex box or whatever. Um, and apparently, you pick three items and then you pick ... He says, "Okay. Pick the first one up with your right hand, the second one up with your left hand. Now, using those objects, those ... now, as tools, pick up the third object." Right? So that's down at the level of, of physics and mechanics and contact mechanics that, um, that I think we do learning ... or we do have policies for, we do control for, almost feedback, but somehow we're able to still ... I mean, I've never picked up a telephone with a shoe and a water bottle before, and somehow ... And it takes me a little longer to do that the first time, but most of the time, we can sort of figure that out. So, yeah, I think the, the amazing thing is this ability to be flexible with our models-

   17. LFLex Fridman1:13:44

       Right.

   18. RTRuss Tedrake1:13:45

       ... um, plan when we need to, use our well-oiled controllers when we don't, when, when we're in familiar territory. Um, having models. I think the oth- the other thing you just said was something about I think your awareness of what's happening is even changing as you, as you get ... as you improve your expertise, right? So, maybe you have a very approximate model of the mechanics to begin with and as you gain expertise, you get a more refined version of that model. You're aware of, of muscles or, or, um, balance components that you were just- weren't even aware of before. So how do you scaffold that?

   19. LFLex Fridman1:14:21

       Yeah. Plus the fear of injury, the ambition of goals, of, uh, excelling, and, uh, fear of mortality. Let's see, what else is in there as motivations? Um, uh, a over inflated ego in the beginning, uh, th- like, and then a crash of confidence in the middle. All those (laughs) seem to be essential for the learning process.

   20. RTRuss Tedrake1:14:46

       And also- ... And if all that's good, then you're probably optimizing energy efficiency.

   21. LFLex Fridman1:14:50

       Yeah. Right. (laughs) So we have to get that right. Uh, so, um, you know, th- there was this idea that you would have, uh, robots play soccer better than human players by 2050. That was the goal. Uh, world ... Basically, uh, was the goal to beat world champion team-

   22. RTRuss Tedrake1:15:10

       Yeah.

   23. LFLex Fridman1:15:10

       ... to become a World Cup ... Be like a World Cup-

   24. RTRuss Tedrake1:15:12

       Right.

   25. LFLex Fridman1:15:12

       ... level team? So, are we gonna see that first or, um, a robot ... If you're familiar, there's a organization called UFC for mixed martial arts. Are we gonna see a World Cup championship soccer team that are robots or a UFC champion mixed martial artist, uh, that's-

   26. RTRuss Tedrake1:15:32

       Ah.

   27. LFLex Fridman1:15:32

       ... a robot?

   28. RTRuss Tedrake1:15:33

       I mean, it's very hard to, to say one thing is harder than ... One ... Some problem is harder than the other. What probably matters, i- is, um-

   29. LFLex Fridman1:15:42

       (laughs)

   30. RTRuss Tedrake1:15:42

       ... who, who, who started the organization that, that ... I mean, I think RoboCup has a pretty serious following and there are ... is a history now of people playing that game, learning about that game, building robots to play that game, building increasingly more human robots. It's got momentum. And so if you want to, uh, to have mixed martial arts compete, you better start your-
10. 1:18:32 – 1:34:01

    Black Mirror Robot Dog

    1. RTRuss Tedrake1:18:32

    2. LFLex Fridman1:18:32

       Let me ask another ridiculous question. Uh, pro- ... I think this, this might be the last ridiculous question, but, uh-

    3. RTRuss Tedrake1:18:38

       I doubt it. (laughs)

    4. LFLex Fridman1:18:39

       (laughs) I, I aspired to ask as many, uh, ridiculous questions of, uh, of a br- brilliant MIT professor. Okay. Uh, I don't know if you've seen the Black Mirror?

    5. RTRuss Tedrake1:18:53

       It's funny, I- I- I never watched the episode. I know when it happened though because I gave a talk to some MIT faculty one day on a- a unassuming, you know, Monday or whatever. I was telling them about the state of robotics, and I showed some video of, from Boston Dynamics of the quadruped Spot at the time, uh, it was their early version of Spot, and there was a look of horror that went across the room.

    6. LFLex Fridman1:19:18

       (laughs)

    7. RTRuss Tedrake1:19:19

       And I said, "What? You know, I've- I've- I've shown videos like this a lot of times. What happened?" And it turns out that this video had gone, uh, this Black Mirror episode had changed the way people watched, um, yeah, the videos I was putting out.

    8. LFLex Fridman1:19:33

       The way they see these kinds of robots, so I- I talked to so many people who are just terrified because of that episode probably of these kinds of robots. They, I almost wanna say they almost kinda like enjoy being terrified. I don't even know what it is about human psychology, that kind of imagine doomsday, the destruction of the universe or our society, and kinda like enjoy being afraid. Um, I don't wanna simplify it, but it feels like they talk about it so often it almost ... They, th- there does seem to be an addictive quality to it. Um, I talked to a guy at, so this, a guy named Joe Rogan who's kinda the flag bearer for being terrified of these robots. (laughs) Uh, do you have a ... Two questions. One, do you have an understanding of why people are afraid of robots? And the second question is, uh, in Black Mirror, just to tell you the episode, I don't even remember it that much anymore, but these robots, I think they can shoot like a pellet or something. They basically have, it's- it's basically a Spot with a gun. And, um, how far are we away from, um, having robots that go rogue like that, you know, basically Spot that goes rogue for some reason and somehow finds a gun. (laughs)

    9. RTRuss Tedrake1:20:51

       Right. So, I mean, I'm, I'm not a psychologist.

    10. LFLex Fridman1:20:55

        (laughs)

    11. RTRuss Tedrake1:20:55

        Um, I think, I don't know exactly why, uh, people react the way they do. Um, I think, I think we have to be careful about the way robots influence our society and the like. I think that's something, that's a responsibility that roboticists need to embrace. Um, I don't think robots are gonna come after me with a kitchen knife or a pellet gun right away, and, I mean, they, if they were programmed in such a way, but I used to joke with Atlas that, um, all I had to do was run for five minutes and its battery would run out. (laughs)

    12. LFLex Fridman1:21:30

        (laughs)

    13. RTRuss Tedrake1:21:30

        But, uh, actually they've got a very big battery in there by the end, so it was over an hour.

    14. LFLex Fridman1:21:35

        (laughs)

    15. RTRuss Tedrake1:21:37

        Um, I think the fear is cu- a bit cultural though 'cause I, I, I mean, you notice that, like, I think in my age in the US we grew up watching Terminator, right? If I had grown up at the same time in Japan, I probably would've been watching Astro Boy, and there's a very different reaction to robots, uh, in different countries, right? So, I don't know if it's a human innate fear of metal marvels or if it's, um, um, something that we've done to ourselves with our sci-fi. (laughs) Uh ...

    16. LFLex Fridman1:22:09

        Yeah, the stories we tell ourselves through, uh, through movies, through just, uh, through popular media. But if- if I were to tell, you know, if- if you were my therapist and I said, "I'm really terrified that, uh, we're going to have these robots, uh, very soon that will hurt us," um, like how do you approach m- making me feel better? Um, like why shouldn't people be afraid? I mean, there's a, I think there's a video that went viral recently. Everything, everything with Spot in- in Boston Dynamics goes viral in general, but usually it's like really cool stuff, like they're doing flips and stuff or like sad stuff with b- s- Atlas being hit with a broomstick or something like that. But, uh, there's a video where I think, um, w- one of the new production Spot robots, which are awesome, it was like patrolling somewhere in like, in some country and like people immediately were like saying like, "This is like the dystopian future, like the surveillance state." For some reason like you could just have a camera, like, well, something about Spot being able to walk on four feet would like really terrified people. So like what, what do you say to those people? I think there is a legitimate fear there because so much of our future is uncertain. Um, but at the same time, technically speaking, it seems like we're not there yet. So what do you say?

    17. RTRuss Tedrake1:23:44

        I mean, I think technology is, um, complicated. It can be used in many ways. I think there are purely software, um, attacks that somebody could use to do great damage. Maybe they have already. Um, you know, I think, uh, wheeled robots could be used in bad ways too.

    18. LFLex Fridman1:24:08

        Drones.

    19. RTRuss Tedrake1:24:10

        Drones, right. Um, I don't think that ... Let's see. I don't want to be, um, building technology just because I'm compelled to build technology and I don't think about it. But I would consider myself a technological optimist I guess, um, in the sense that I think we should continue to create and evolve and our world will change. Um, and if w- we're, we will introduce new challenges, we'll screw something up maybe, but I think also we'll invent ourselves out of those challenges and life will go on.

    20. LFLex Fridman1:24:49

        So, it's interesting 'cause you, you didn't mention like this is technically too hard.

    21. RTRuss Tedrake1:24:53

        Mm-hmm.I don't think robots are... I think people attribute a robot that looks like an animal as maybe having a level of self-awareness or- or consciousness, or something that they don't have yet, right? So, it's not, I think our ability to anthropomorphize those robots is probably, um, we're assuming that they have a level of intelligence that they don't yet have, and that might be part of the fear. So, in that sense, it's too hard. But, um, you know, there are many scary things in the world, right? So, uh, I think we're right to ask those questions, we're right to, um, think about the implications of our work.

Episode duration: 2:48:46