Trajectory Estimation of Human Mass Center Based on an Inertia Identification Approach

Mass center of a human body is not a fixed point on the human body because the inertia distribution of the human body changes with body posture. Real-time estimation of the location of human mass center is often required for many biomechanical or biomedical applications. This is not an easy task if the inertia properties of the human’s body segments are unknown. This paper presents a technique for estimating the trajectory of the human mass center based on a recently developed inertia properties identification technology which was derived based on the impulse-momentum principle. The proposed technique assumes a human body as a general treelike multibody system, such that the mass center of the human is predictable with the knowledge of the barycentric parameters of the human. The latter can be identified using inertia identification method. This technique is advantageous because it requires only the 3D motion capture data as its primary input and does not need to know the inertia and geometric parameters of individual body segments of the human. The paper presents a dynamic simulation based study of the proposed estimation technique and also describes an ongoing experimental testing.