Bipedal walking pattern design based on synchronization of the motions in sagittal and lateral planes

In this paper, a new design approach of bipedal walking pattern based on the synchronization of the motions in sagittal and lateral planes are presented and two walking patterns of ZMP fixed and ZMP variable cases are developed. Based on our previous work, bipedal walking is separated into the initial acceleration, double support, deceleration, and acceleration phases; consequently, the nature that bipedal walking is in fact a continuous acceleration and deceleration motion is revealed. With the discusses on the motions both in the sagittal and lateral planes, the fact that the motions in these two planes are tightly coupled together is clarified. The motion parameters such as the walking velocity, walking time, and phase stride can be easily changed simply by altering the swinging amplitude in lateral plane that is determined by the double support phase. The constraint conditions of the phase stride, velocity and swinging amplitude are investigated. Therefore, an approach for adjusting walking velocity by controlling the swinging amplitude is naturally developed. The motion planning is also presented and a numerical example is given out.