position statiquement stable

OBS: [...] la condition nécessaire et suffisante pour qu'un aéronef soit statiquement stable en vol est que son centre de gravité soit situé en avant d'un point bien particulier, le foyer aérodynamique (ou foyer tout court) global de l'appareil.

CONT: Principles of gyroscopic action. ... Dynamic stability. When the cone sits on its base on a flat surface and is tipped slightly, it returns to its original position when the tipping force is removed. This is said to be a statically stable position. If the cone is turned over, it may momentarily be possible to balance it on its pointed end, but the slightest tipping force will make it fall on its side. The latter position is said to be statically unstable.
CONT: The aim of this section is to calculate the torques which have to be generated in the leg joints to hold the leg in a statically stable position. Dynamic forces will not be taken into consideration, since all movements of the robot are slow. First, the torques will be calculated as functions of the leg geometry, position, and the weight to be supported by the leg. Afterwards, these general expressions will be evaluated for a real robot leg.