Dynamic instant gait stability measure for quadruped walking robot

A mathematic model is developed for a quadruped walking robot to investigate the dynamic stability considering all the inertial effects in the system including those of legs. The dynamic model is derived based on Lagrange's equation using matrix-vector notations for the simpler expression. Then an instant gait stability measure is proposed to apply to dynamic gait as well as static gait. The gait stability measure is obtained from the angular momentum of the system about the supporting edges in the quadrupedal gait of +x type. The validity of the gait stability measure is examined along with the gait stability analysis for several representative gait parameters using the developed dynamic model.