双足机器人行走稳定性研究

Walking stability in bipedal robots

双足机器人行走的稳定性是双足行走最为重要的衡量指标之一.针对传统的基于零力矩点(ZMP)步态稳定性判据方法,分析了ZMP、COP的相互关系,表明在双足机器人与水平地面无粘性力和无吸附力作用下,其ZMP即为压力中心点COP.基于具有足趾关节的双足机器人足底支撑面多种变化,提出对多点接触时支撑多边形区域描述.结合ZMP/COP、COG的在支撑面内相对位置,提出了基于ZMP/COP、COG的综合稳定性判据.经仿真分析,与传统单一的ZMP稳定性判据相比,该综合稳定性判据能够更为准确地反映步态的稳定性.

Stable walking is one of the most important measurement indexes for the movement of bipedal robots. After reviewing the traditional gait stability criterion based on zero moment point （ZMP）, the authors analyzed the relationship between ZMP and the center of pressure （COP） , and concluded that the ZMP of a bipedal robot is the COP of that bipedal robot if there is neither viscous force nor adsorption force between the biped robot and its horizontal footing. After analyzing differences in humanoid walking gaits caused by differences in supporting surfaces, the authors proposed a method for describing the supporting surface in a way that satisfies regional descriptions of support polygons under conditions of multipoint contact. Based on comprehensive consideration of the position of ZMP/COP and the center of gravity （COG） in the supporting surface, criteria for comprehensive stability were put forward. The results of simulations and experiments show that this method is more accurate than traditional criteria for comprehensive evaluation of a gait＇s stability.