WEBVTT 00:00:11.544 --> 00:00:14.067 So what does it mean for a machine to be athletic? 00:00:15.059 --> 00:00:17.884 We will demonstrate the concept of machine athleticism 00:00:17.908 --> 00:00:19.604 and the research to achieve it 00:00:19.628 --> 00:00:22.486 with the help of these flying machines called quadrocopters, 00:00:22.510 --> 00:00:23.557 or quads, for short. NOTE Paragraph 00:00:26.291 --> 00:00:28.184 Quads have been around for a long time. 00:00:28.501 --> 00:00:31.778 They're so popular these days because they're mechanically simple. 00:00:32.255 --> 00:00:34.644 By controlling the speeds of these four propellers, 00:00:34.668 --> 00:00:37.413 these machines can roll, pitch, yaw, 00:00:37.437 --> 00:00:39.608 and accelerate along their common orientation. 00:00:40.179 --> 00:00:43.377 On board are also a battery, a computer, 00:00:43.401 --> 00:00:45.354 various sensors and wireless radios. NOTE Paragraph 00:00:47.298 --> 00:00:50.607 Quads are extremely agile, but this agility comes at a cost. 00:00:51.762 --> 00:00:53.850 They are inherently unstable, 00:00:53.874 --> 00:00:56.445 and they need some form of automatic feedback control 00:00:56.469 --> 00:00:57.842 in order to be able to fly. NOTE Paragraph 00:01:04.259 --> 00:01:06.512 So, how did it just do that? 00:01:07.497 --> 00:01:09.291 Cameras on the ceiling and a laptop 00:01:09.315 --> 00:01:11.745 serve as an indoor global positioning system. 00:01:12.301 --> 00:01:14.340 It's used to locate objects in the space 00:01:14.364 --> 00:01:16.452 that have these reflective markers on them. 00:01:16.476 --> 00:01:18.514 This data is then sent to another laptop 00:01:18.538 --> 00:01:20.896 that is running estimation and control algorithms, 00:01:20.920 --> 00:01:22.874 which in turn sends commands to the quad, 00:01:22.898 --> 00:01:25.531 which is also running estimation and control algorithms. 00:01:29.864 --> 00:01:32.106 The bulk of our research is algorithms. 00:01:32.130 --> 00:01:34.706 It's the magic that brings these machines to life. NOTE Paragraph 00:01:36.291 --> 00:01:40.324 So how does one design the algorithms that create a machine athlete? 00:01:40.792 --> 00:01:43.379 We use something broadly called model-based design. 00:01:43.839 --> 00:01:45.205 We first capture the physics 00:01:45.229 --> 00:01:48.212 with a mathematical model of how the machines behave. 00:01:48.636 --> 00:01:52.586 We then use a branch of mathematics called control theory 00:01:52.610 --> 00:01:54.267 to analyze these models 00:01:54.291 --> 00:01:57.061 and also to synthesize algorithms for controlling them. 00:01:57.820 --> 00:02:00.844 For example, that's how we can make the quad hover. 00:02:00.868 --> 00:02:04.158 We first captured the dynamics with a set of differential equations. 00:02:04.182 --> 00:02:07.634 We then manipulate these equations with the help of control theory 00:02:07.658 --> 00:02:10.595 to create algorithms that stabilize the quad. NOTE Paragraph 00:02:11.130 --> 00:02:13.423 Let me demonstrate the strength of this approach. 00:02:17.198 --> 00:02:19.831 Suppose that we want this quad to not only hover 00:02:19.855 --> 00:02:21.514 but to also balance this pole. 00:02:22.520 --> 00:02:24.294 With a little bit of practice, 00:02:24.318 --> 00:02:27.001 it's pretty straightforward for a human being to do this, 00:02:27.025 --> 00:02:30.216 although we do have the advantage of having two feet on the ground 00:02:30.240 --> 00:02:32.299 and the use of our very versatile hands. 00:02:32.804 --> 00:02:35.542 It becomes a little bit more difficult 00:02:35.566 --> 00:02:37.545 when I only have one foot on the ground 00:02:37.569 --> 00:02:39.171 and when I don't use my hands. 00:02:40.733 --> 00:02:43.295 Notice how this pole has a reflective marker on top, 00:02:43.319 --> 00:02:45.980 which means that it can be located in the space. NOTE Paragraph 00:02:52.276 --> 00:02:53.343 (Audience) Oh! NOTE Paragraph 00:02:53.367 --> 00:02:54.626 (Applause) NOTE Paragraph 00:02:57.695 --> 00:02:59.363 (Applause ends) NOTE Paragraph 00:02:59.387 --> 00:03:02.028 You can notice that this quad is making fine adjustments 00:03:02.052 --> 00:03:03.426 to keep the pole balanced. 00:03:04.417 --> 00:03:06.489 How did we design the algorithms to do this? 00:03:07.027 --> 00:03:09.108 We added the mathematical model of the pole 00:03:09.132 --> 00:03:10.579 to that of the quad. 00:03:10.603 --> 00:03:13.581 Once we have a model of the combined quad-pole system, 00:03:13.605 --> 00:03:16.924 we can use control theory to create algorithms for controlling it. 00:03:18.538 --> 00:03:20.102 Here, you see that it's stable, 00:03:20.126 --> 00:03:22.795 and even if I give it little nudges, 00:03:22.819 --> 00:03:23.985 it goes back -- 00:03:25.589 --> 00:03:27.358 to the nice, balanced position. NOTE Paragraph 00:03:28.087 --> 00:03:29.477 We can also augment the model 00:03:29.501 --> 00:03:31.872 to include where we want the quad to be in space. 00:03:32.428 --> 00:03:35.371 Using this pointer, made out of reflective markers, 00:03:35.395 --> 00:03:37.824 I can point to where I want the quad to be in space 00:03:37.848 --> 00:03:39.445 a fixed distance away from me. NOTE Paragraph 00:03:47.785 --> 00:03:49.665 (Laughter) NOTE Paragraph 00:03:55.763 --> 00:03:58.889 The key to these acrobatic maneuvers is algorithms, 00:03:58.913 --> 00:04:01.206 designed with the help of mathematical models 00:04:01.230 --> 00:04:02.415 and control theory. NOTE Paragraph 00:04:03.246 --> 00:04:05.231 Let's tell the quad to come back here 00:04:05.255 --> 00:04:06.919 and let the pole drop, 00:04:06.943 --> 00:04:09.074 and I will next demonstrate the importance 00:04:09.098 --> 00:04:11.087 of understanding physical models 00:04:11.111 --> 00:04:13.156 and the workings of the physical world. 00:04:25.462 --> 00:04:29.290 Notice how the quad lost altitude when I put this glass of water on it. 00:04:29.314 --> 00:04:30.717 Unlike the balancing pole, 00:04:30.741 --> 00:04:33.756 I did not include the mathematical model of the glass 00:04:33.780 --> 00:04:35.087 in the system. 00:04:35.111 --> 00:04:38.124 In fact, the system doesn't even know that the glass is there. 00:04:38.148 --> 00:04:40.886 Like before, I could use the pointer to tell the quad 00:04:40.910 --> 00:04:42.481 where I want it to be in space. NOTE Paragraph 00:04:45.684 --> 00:04:47.483 (Applause) NOTE Paragraph 00:04:51.531 --> 00:04:53.071 (Applause ends) NOTE Paragraph 00:04:53.515 --> 00:04:55.254 Okay, you should be asking yourself, 00:04:55.278 --> 00:04:57.340 why doesn't the water fall out of the glass? 00:04:57.888 --> 00:04:58.918 Two facts. 00:04:58.942 --> 00:05:02.575 The first is that gravity acts on all objects in the same way. 00:05:03.051 --> 00:05:04.830 The second is that the propellers 00:05:04.854 --> 00:05:07.927 are all pointing in the same direction of the glass, pointing up. 00:05:08.642 --> 00:05:10.289 You put these two things together, 00:05:10.313 --> 00:05:13.868 the net result is that all side forces on the glass are small 00:05:13.892 --> 00:05:16.169 and are mainly dominated by aerodynamic effects, 00:05:16.193 --> 00:05:18.154 which at these speeds are negligible. 00:05:23.336 --> 00:05:25.670 And that's why you don't need to model the glass. 00:05:25.694 --> 00:05:28.435 It naturally doesn't spill, no matter what the quad does. NOTE Paragraph 00:05:32.500 --> 00:05:35.063 (Audience) Oh! NOTE Paragraph 00:05:38.340 --> 00:05:40.198 (Applause) NOTE Paragraph 00:05:43.159 --> 00:05:44.414 (Applause ends) NOTE Paragraph 00:05:45.940 --> 00:05:47.054 The lesson here 00:05:47.078 --> 00:05:51.091 is that some high-performance tasks are easier than others, 00:05:51.115 --> 00:05:53.452 and that understanding the physics of the problem 00:05:53.476 --> 00:05:56.170 tells you which ones are easy and which ones are hard. 00:05:56.194 --> 00:05:58.704 In this instance, carrying a glass of water is easy. 00:05:58.728 --> 00:06:00.358 Balancing a pole is hard. NOTE Paragraph 00:06:02.171 --> 00:06:06.442 We've all heard stories of athletes performing feats while physically injured. 00:06:06.466 --> 00:06:09.651 Can a machine also perform with extreme physical damage? 00:06:10.636 --> 00:06:12.121 Conventional wisdom says 00:06:12.145 --> 00:06:16.028 that you need at least four fixed motor propeller pairs in order to fly, 00:06:16.052 --> 00:06:18.576 because there are four degrees of freedom to control: 00:06:18.600 --> 00:06:20.565 roll, pitch, yaw and acceleration. 00:06:21.192 --> 00:06:24.413 Hexacopters and octocopters, with six and eight propellers, 00:06:24.437 --> 00:06:25.896 can provide redundancy, 00:06:25.920 --> 00:06:27.885 but quadrocopters are much more popular 00:06:27.909 --> 00:06:31.595 because they have the minimum number of fixed motor propeller pairs: four. 00:06:32.168 --> 00:06:33.184 Or do they? NOTE Paragraph 00:06:40.827 --> 00:06:41.827 (Audience) Oh! NOTE Paragraph 00:06:42.407 --> 00:06:43.407 (Laughter) NOTE Paragraph 00:06:49.334 --> 00:06:52.052 If we analyze the mathematical model of this machine 00:06:52.076 --> 00:06:54.228 with only two working propellers, 00:06:54.252 --> 00:06:56.992 we discover that there's an unconventional way to fly it. 00:07:07.980 --> 00:07:09.662 We relinquish control of yaw, 00:07:09.686 --> 00:07:12.732 but roll, pitch and acceleration can still be controlled 00:07:12.756 --> 00:07:16.102 with algorithms that exploit this new configuration. 00:07:21.668 --> 00:07:25.957 Mathematical models tell us exactly when and why this is possible. 00:07:25.981 --> 00:07:28.759 In this instance, this knowledge allows us to design 00:07:28.783 --> 00:07:31.256 novel machine architectures 00:07:31.280 --> 00:07:34.948 or to design clever algorithms that gracefully handle damage, 00:07:34.972 --> 00:07:36.672 just like human athletes do, 00:07:36.696 --> 00:07:38.960 instead of building machines with redundancy. NOTE Paragraph 00:07:40.688 --> 00:07:42.345 We can't help but hold our breath 00:07:42.369 --> 00:07:45.044 when we watch a diver somersaulting into the water, 00:07:45.068 --> 00:07:47.021 or when a vaulter is twisting in the air, 00:07:47.045 --> 00:07:48.552 the ground fast approaching. 00:07:48.576 --> 00:07:51.120 Will the diver be able to pull off a rip entry? 00:07:51.144 --> 00:07:52.951 Will the vaulter stick the landing? 00:07:53.292 --> 00:07:56.472 Suppose we want this quad here to perform a triple flip 00:07:56.496 --> 00:07:59.322 and finish off at the exact same spot that it started. 00:07:59.736 --> 00:08:01.855 This maneuver is going to happen so quickly 00:08:01.879 --> 00:08:05.724 that we can't use position feedback to correct the motion during execution. 00:08:05.748 --> 00:08:07.345 There simply isn't enough time. 00:08:07.782 --> 00:08:11.452 Instead, what the quad can do is perform the maneuver blindly, 00:08:11.476 --> 00:08:13.684 observe how it finishes the maneuver, 00:08:13.708 --> 00:08:16.185 and then use that information to modify its behavior 00:08:16.209 --> 00:08:17.847 so that the next flip is better. 00:08:18.421 --> 00:08:20.209 Similar to the diver and the vaulter, 00:08:20.233 --> 00:08:22.128 it is only through repeated practice 00:08:22.152 --> 00:08:24.295 that the maneuver can be learned and executed 00:08:24.319 --> 00:08:25.561 to the highest standard. NOTE Paragraph 00:08:33.100 --> 00:08:34.369 (Laughter) NOTE Paragraph 00:08:34.393 --> 00:08:38.178 (Applause) NOTE Paragraph 00:08:39.164 --> 00:08:42.612 Striking a moving ball is a necessary skill in many sports. 00:08:43.127 --> 00:08:44.619 How do we make a machine do 00:08:44.643 --> 00:08:47.231 what an athlete does seemingly without effort? NOTE Paragraph 00:08:57.547 --> 00:08:59.054 (Laughter) NOTE Paragraph 00:09:04.143 --> 00:09:06.000 (Applause) NOTE Paragraph 00:09:08.500 --> 00:09:09.798 (Applause ends) NOTE Paragraph 00:09:10.542 --> 00:09:13.168 This quad has a racket strapped onto its head 00:09:13.192 --> 00:09:16.655 with a sweet spot roughly the size of an apple, so not too large. 00:09:17.017 --> 00:09:19.822 The following calculations are made every 20 milliseconds, 00:09:19.846 --> 00:09:21.163 or 50 times per second. 00:09:21.602 --> 00:09:23.877 We first figure out where the ball is going. 00:09:24.414 --> 00:09:27.035 We then next calculate how the quad should hit the ball 00:09:27.059 --> 00:09:29.544 so that it flies to where it was thrown from. 00:09:29.950 --> 00:09:34.382 Third, a trajectory is planned that carries the quad 00:09:34.406 --> 00:09:37.406 from its current state to the impact point with the ball. 00:09:37.430 --> 00:09:41.009 Fourth, we only execute 20 milliseconds' worth of that strategy. 00:09:41.366 --> 00:09:44.159 Twenty milliseconds later, the whole process is repeated 00:09:44.183 --> 00:09:45.950 until the quad strikes the ball. NOTE Paragraph 00:09:55.290 --> 00:09:57.694 (Applause) NOTE Paragraph 00:09:58.131 --> 00:10:01.554 Machines can not only perform dynamic maneuvers on their own, 00:10:01.578 --> 00:10:03.417 they can do it collectively. 00:10:03.441 --> 00:10:07.028 These three quads are cooperatively carrying a sky net. NOTE Paragraph 00:10:15.589 --> 00:10:17.268 (Applause) NOTE Paragraph 00:10:20.372 --> 00:10:21.961 (Applause ends) NOTE Paragraph 00:10:21.985 --> 00:10:26.326 They perform an extremely dynamic and collective maneuver 00:10:26.350 --> 00:10:28.018 to launch the ball back to me. 00:10:28.042 --> 00:10:31.188 Notice that, at full extension, these quads are vertical. NOTE Paragraph 00:10:36.486 --> 00:10:38.234 (Applause) NOTE Paragraph 00:10:38.258 --> 00:10:40.401 In fact, when fully extended, 00:10:40.425 --> 00:10:43.688 this is roughly five times greater than what a bungee jumper feels 00:10:43.712 --> 00:10:45.682 at the end of their launch. NOTE Paragraph 00:10:51.203 --> 00:10:53.662 The algorithms to do this are very similar 00:10:53.686 --> 00:10:56.601 to what the single quad used to hit the ball back to me. 00:10:57.070 --> 00:10:59.910 Mathematical models are used to continuously re-plan 00:10:59.934 --> 00:11:02.765 a cooperative strategy 50 times per second. NOTE Paragraph 00:11:04.506 --> 00:11:08.765 Everything we have seen so far has been about the machines and their capabilities. 00:11:08.789 --> 00:11:11.781 What happens when we couple this machine athleticism 00:11:11.805 --> 00:11:13.288 with that of a human being? 00:11:13.765 --> 00:11:17.361 What I have in front of me is a commercial gesture sensor 00:11:17.385 --> 00:11:18.670 mainly used in gaming. 00:11:18.694 --> 00:11:20.742 It can recognize what my various body parts 00:11:20.766 --> 00:11:22.083 are doing in real time. 00:11:22.710 --> 00:11:24.789 Similar to the pointer that I used earlier, 00:11:24.813 --> 00:11:27.035 we can use this as inputs to the system. 00:11:27.454 --> 00:11:29.826 We now have a natural way of interacting 00:11:29.850 --> 00:11:33.111 with the raw athleticism of these quads with my gestures. NOTE Paragraph 00:12:10.715 --> 00:12:14.572 (Applause) NOTE Paragraph 00:12:24.354 --> 00:12:26.370 Interaction doesn't have to be virtual. 00:12:26.394 --> 00:12:27.584 It can be physical. 00:12:27.989 --> 00:12:29.504 Take this quad, for example. 00:12:29.893 --> 00:12:32.116 It's trying to stay at a fixed point in space. 00:12:32.933 --> 00:12:36.622 If I try to move it out of the way, it fights me, 00:12:36.646 --> 00:12:38.520 and moves back to where it wants to be. 00:12:40.254 --> 00:12:42.341 We can change this behavior, however. 00:12:43.373 --> 00:12:45.048 We can use mathematical models 00:12:45.072 --> 00:12:47.736 to estimate the force that I'm applying to the quad. 00:12:48.205 --> 00:12:51.419 Once we know this force, we can also change the laws of physics, 00:12:51.443 --> 00:12:53.530 as far as the quad is concerned, of course. 00:12:55.942 --> 00:12:59.251 Here, the quad is behaving as if it were in a viscous fluid. NOTE Paragraph 00:13:02.570 --> 00:13:06.289 We now have an intimate way of interacting with a machine. 00:13:06.593 --> 00:13:09.075 I will use this new capability to position 00:13:09.099 --> 00:13:11.652 this camera-carrying quad to the appropriate location 00:13:11.676 --> 00:13:14.104 for filming the remainder of this demonstration. NOTE Paragraph 00:13:24.583 --> 00:13:26.966 So we can physically interact with these quads 00:13:26.990 --> 00:13:28.950 and we can change the laws of physics. 00:13:29.393 --> 00:13:31.370 Let's have a little bit of fun with this. 00:13:31.539 --> 00:13:32.908 For what you will see next, 00:13:32.932 --> 00:13:36.226 these quads will initially behave as if they were on Pluto. 00:13:36.906 --> 00:13:39.194 As time goes on, gravity will be increased 00:13:39.218 --> 00:13:41.243 until we're all back on planet Earth, 00:13:41.267 --> 00:13:43.033 but I assure you we won't get there. 00:13:43.462 --> 00:13:44.486 Okay, here goes. NOTE Paragraph 00:13:52.897 --> 00:13:54.448 (Laughter) NOTE Paragraph 00:14:22.778 --> 00:14:25.738 (Laughter) NOTE Paragraph 00:14:25.858 --> 00:14:29.619 (Applause) NOTE Paragraph 00:14:29.760 --> 00:14:30.826 Whew! 00:14:35.045 --> 00:14:36.272 You're all thinking now, 00:14:36.296 --> 00:14:38.247 these guys are having way too much fun, 00:14:38.271 --> 00:14:40.326 and you're probably also asking yourself, 00:14:40.350 --> 00:14:43.151 why exactly are they building machine athletes? 00:14:44.286 --> 00:14:47.096 Some conjecture that the role of play in the animal kingdom 00:14:47.120 --> 00:14:49.257 is to hone skills and develop capabilities. 00:14:49.690 --> 00:14:51.905 Others think that it has more of a social role, 00:14:51.929 --> 00:14:53.579 that it's used to bind the group. 00:14:53.603 --> 00:14:56.939 Similarly, we use the analogy of sports and athleticism 00:14:56.963 --> 00:14:59.018 to create new algorithms for machines 00:14:59.042 --> 00:15:00.485 to push them to their limits. 00:15:01.350 --> 00:15:04.398 What impact will the speed of machines have on our way of life? 00:15:04.866 --> 00:15:07.231 Like all our past creations and innovations, 00:15:07.255 --> 00:15:10.058 they may be used to improve the human condition 00:15:10.082 --> 00:15:12.056 or they may be misused and abused. 00:15:12.595 --> 00:15:14.897 This is not a technical choice we are faced with; 00:15:14.921 --> 00:15:15.936 it's a social one. 00:15:16.332 --> 00:15:17.683 Let's make the right choice, 00:15:17.707 --> 00:15:20.619 the choice that brings out the best in the future of machines, 00:15:20.643 --> 00:15:23.508 just like athleticism in sports can bring out the best in us. NOTE Paragraph 00:15:24.380 --> 00:15:27.455 Let me introduce you to the wizards behind the green curtain. 00:15:27.479 --> 00:15:30.813 They're the current members of the Flying Machine Arena research team. NOTE Paragraph 00:15:30.837 --> 00:15:35.054 (Applause) NOTE Paragraph 00:15:35.267 --> 00:15:37.545 Federico Augugliaro, Dario Brescianini, 00:15:37.569 --> 00:15:40.994 Markus Hehn, Sergei Lupashin, Mark Muller and Robin Ritz. 00:15:41.018 --> 00:15:43.542 Look out for them. They're destined for great things. NOTE Paragraph 00:15:43.566 --> 00:15:44.620 Thank you. NOTE Paragraph 00:15:44.644 --> 00:15:48.100 (Applause)