Effects of the Initial Stance of Quadruped Trotting on Stability

It is important for quadruped walking machine to keep its stability in high speed walking. The moment around the supporting axis of quadruped trotting was modeled and its effects on the body attitude were analyzed. A conclusion was drawn that the angle of rotation around the supporting diagonal line is proportional to the multiplication of square of walking period and stride length. A new method called trichotomy about initial stance was brought forward to minimize the bad effects of the moment on body attitude. The method works very well in the simulations.