A geometric method for center of mass estimation in rough planar terrains

Center of Mass(CoM) estimation in rough terrains is hampered by complicated body dynamics yet remains critically important in the study of human and robot motion planning. Current techniques for CoM estimation are encumbered by lengthy calibration periods requiring the use of specialized tools(force plates, motion capture, etc). This paper presents a novel and straightforward geometric method for CoM estimation over rough planar terrains that relies solely on geometry information of the environment and essential knowledge of the kinematic body. The CoM is approximated using a simplified model of the contact foot locations and an Optimized Geometric Hermite(OGH) curve with minimum curvature and length. To evaluate the accuracy of the method, cross validation with human subjects was performed. The results demonstrate that the geometric method delivers an accurate approximation of the CoM path for natural walking over rough planar terrains and offers a reliable alternative for CoM estimation.