MechE Colloquium: Passive Dynamics is a Good Basis for Robot Design and Control
Event details
| Date | 02.04.2019 |
| Hour | 12:15 › 13:15 |
| Speaker | Prof. Andy Ruina, Mechanical Engineering, Cornell University |
| Location | |
| Category | Conferences - Seminars |
Abstract:
Many airplanes can, or nearly can, glide stably without control. So, it seems natural that the first successful powered flight followed from mastery of gliding. Many bicycles can, or nearly can, balance themselves when in motion. Bicycle design seems to have evolved to gain this feature. Also, we can make toys and ‘robots’ that, like a stable glider or coasting bicycle, stably walk without motors or control in a remarkably human-like way. Again, it seems to make sense to use `passive-dynamics’ as a core for developing the control of walking robots and to gain understanding of the control of walking people. That's what I used to think. But, so far, this passive approach has not led to robust walking robots. What about human evolution? We didn’t evolve dynamic bodies and then learn to control them. Rather, people had elaborate control systems way back when we were fish and even worms. However: if control is paramount, why is it that uncontrolled passive-dynamic walkers walk so much like humans? It seems that energy optimal, yet robust, control, perhaps a proxy for evolutionary development, arrives at solutions that have some features in common with passive-dynamics. Instead of thinking of good powered walking as passive walking with a small amount of control added, I now think of good powered walking, human or robotic, as highly controlled, while optimized mostly for avoiding falls and, secondarily, for minimal actuator use. When well done, much of the motor effort, always at the ready, is usually titrated out. Thus, deceptively looking, “passive”.
Bio:
Andy Ruina has 3 Engineering degrees, essentially in engineering mechanics, from Brown University. He was a recipient of the National Science Foundation's Presidential Young Investigator Award (similar to the more recent NSF Career Award). He has been a Professor at Cornell since 1980, initially in Theoretical and Applied Mechanics (TAM) and now in Mechanical Engineering (ME). He has taught about 7,000 students and got the Engineering College's biggest teaching prize in 2015), had about 200 students do projects in his lab, had 14 completed PhDs, about 10 short-term foreign visitors and a few post-docs. His Ph.D. training was in solid mechanics (stress and strain). His research has gone from friction and earthquakes to collisions, bicycles (e.g., stability eigenvalues), biomechanics and robotics (mostly balance and energetics). I knows some dynamics and dynamical system. Most of his teaching has been in solid mechanics, dynamics, engineering math and robotics. His academic value is more related to mechanical intuition than to mathematical formalism. I has written a 1000-page undergraduate textbook and about 60, peer-reviewed papers. These are cited about 1000 times per year. Twenty six of the papers have been cited over 100 times, and three papers have been cited over 1,000 times.
Many airplanes can, or nearly can, glide stably without control. So, it seems natural that the first successful powered flight followed from mastery of gliding. Many bicycles can, or nearly can, balance themselves when in motion. Bicycle design seems to have evolved to gain this feature. Also, we can make toys and ‘robots’ that, like a stable glider or coasting bicycle, stably walk without motors or control in a remarkably human-like way. Again, it seems to make sense to use `passive-dynamics’ as a core for developing the control of walking robots and to gain understanding of the control of walking people. That's what I used to think. But, so far, this passive approach has not led to robust walking robots. What about human evolution? We didn’t evolve dynamic bodies and then learn to control them. Rather, people had elaborate control systems way back when we were fish and even worms. However: if control is paramount, why is it that uncontrolled passive-dynamic walkers walk so much like humans? It seems that energy optimal, yet robust, control, perhaps a proxy for evolutionary development, arrives at solutions that have some features in common with passive-dynamics. Instead of thinking of good powered walking as passive walking with a small amount of control added, I now think of good powered walking, human or robotic, as highly controlled, while optimized mostly for avoiding falls and, secondarily, for minimal actuator use. When well done, much of the motor effort, always at the ready, is usually titrated out. Thus, deceptively looking, “passive”.
Bio:
Andy Ruina has 3 Engineering degrees, essentially in engineering mechanics, from Brown University. He was a recipient of the National Science Foundation's Presidential Young Investigator Award (similar to the more recent NSF Career Award). He has been a Professor at Cornell since 1980, initially in Theoretical and Applied Mechanics (TAM) and now in Mechanical Engineering (ME). He has taught about 7,000 students and got the Engineering College's biggest teaching prize in 2015), had about 200 students do projects in his lab, had 14 completed PhDs, about 10 short-term foreign visitors and a few post-docs. His Ph.D. training was in solid mechanics (stress and strain). His research has gone from friction and earthquakes to collisions, bicycles (e.g., stability eigenvalues), biomechanics and robotics (mostly balance and energetics). I knows some dynamics and dynamical system. Most of his teaching has been in solid mechanics, dynamics, engineering math and robotics. His academic value is more related to mechanical intuition than to mathematical formalism. I has written a 1000-page undergraduate textbook and about 60, peer-reviewed papers. These are cited about 1000 times per year. Twenty six of the papers have been cited over 100 times, and three papers have been cited over 1,000 times.
Practical information
- General public
- Free