Passive walking with knees

It is shown that passive dynamic walking, a phenomenon originally described for bipeds having straight legs, also works with knees. Thus, giving only a downhill slope as a source of energy, a human-like pair of legs will settle into a natural gait generated by the passive interaction of gravity and inertia. No muscular input is required. The physics is much the same as in straight-legged walking, but the knee-jointed form has two advantages: it offers a simple solution to the problem of foot clearance during the recovery phase, and, in some cases, it is more stable