Passive dynamics
From Wikipedia, the free encyclopedia
Passive dynamics is an approach to robotic movement control (especially walking), based on utilising the momentum of swinging limbs for greater efficiency.
The term and its principles were developed by Tad McGeer in the late 1980s. While at Simon Fraser University in Burnaby, British Columbia, McGeer showed that a humanlike frame can walk itself down a slope without requiring muscles or motors. Unlike traditional robots, which guzzle energy by using motors to control every motion, McGeer's early passive-dynamic robots relied only on gravity and the natural swinging of their limbs to move forward.
Energy efficiency in level-ground transport is quantified in terms of the dimensionless specific cost of transport, which is the amount of energy required to carry a unit weight a unit distance(1). Passive dynamic walkers such as the Cornell biped(2) have the same specific cost of transport as humans, 0.20. Not incidentally, passive dynamic walkers have humanlike gaits. By comparison, Honda's biped ASIMO, which does not utilize the passive dynamics of its own limbs, has a specific cost of transport of 3.23(3).
[edit] References
- Tad McGeer (October 1990). "Passive dynamic walking". International Journal of Robotics Research.
- Note (1): V. A. Tucker (1975). "The energetic cost of moving about". American Scientist 63: 413-419.
- Note (2): Steve H Collins; Martijn Wisse; Andy Ruina (2001). "A 3-D Passive Dynamic Walking Robot with Two Legs and Knees". International Journal of Robotics Research 20: 607-615.
- Note (3): Steve H Collins; Martijn Wisse; Andy Ruina; Russ Tedrake (2005). "Efficient bipedal robots based on passive-dynamic Walkers". Science 307: 1082-1085. and Steve H Collins; Andy Ruina (2005). "A bipedal walking robot with efficient and human-like gait". Proc. IEEE International Conference on Robotics and Automation.
[edit] External links
- MIT Leg Lab — the first passive dynamic walkers
- Droid Logic — simulations of passive dynamic walkers and runners created using evolutionary robotics
- SIGMO Robot — passive dynamic walker based on modifications to McGeer's designs
