Center of mass estimation in irregular planar terrains using a geometric approach

Locomotion maneuvers over irregular terrains involve complex forces and movements that make estimation of center of mass(CoM) behavior a challenging task. Nevertheless, understanding CoM dynamics remains pivotal in locomotion planning for both humans and robots. Current methods for CoM position estimation rely heavily on expensive and ungainly tools, for example force plates, that render CoM analysis impractical and time consuming. To tackle these challenges, this paper proposes an efficient and reliable geometric approach for CoM estimation that delivers accurate CoM behavior in irregular planar terrains. The geometric approach depends only on terrain geometry information and essential kinematic data of the moving body. Using this key information in conjunction with an Optimized Geometric Hermite(OGH) curve, a model is developed that produces accurate CoM position and phase space behavior. Various human case studies were analyzed to validate the effectiveness of the approach. The results show that for natural walking over irregular planar terrains, the geometric approach generates accurate CoM path approximations and state space trajectories and is a powerful tool for understanding CoM position in irregular planar terrains.