DOI: 10.1177/027836499000900206 ISSN:

Passive Dynamic Walking

Tad McGeer
  • Applied Mathematics
  • Artificial Intelligence
  • Electrical and Electronic Engineering
  • Mechanical Engineering
  • Modeling and Simulation
  • Software

There exists a class of two-legged machines for which walking is a natural dynamic mode. Once started on a shallow slope, a machine of this class will settle into a steady gait quite comparable to human walking, without active control or en ergy input. Interpretation and analysis of the physics are straightforward; the walking cycle, its stability, and its sensi tivity to parameter variations are easily calculated. Experi ments with a test machine verify that the passive walking effect can be readily exploited in practice. The dynamics are most clearly demonstrated by a machine powered only by gravity, but they can be combined easily with active energy input to produce efficient and dextrous walking over a broad range of terrain.