Chapter 20 Modeling and Measurement of a Pedestrian’s Center-of-Mass Trajectory Albert R. Ortiz, Bartlomiej Blachowski, Pawel Holobut, Jean M. Franco, Johannio Marulanda, and Peter Thomson Abstract This paper presents the measurement and model updating of a pedestrian’s center of mass trajectory. A mathematical model proposed by the authors is updated using the actual trajectory of a pedestrian. The mathematical model is based on the principle that a human’s control capability tries to maintain balance with respect to the pedestrian’s center of mass (CoM), independently of the surface type. In this research, the human is considered as a mass point concentrated at CoM. The parameters of the models are updated using experimental identification of the human walking trajectory on a rigid surface. The proposed measurement technique uses a depth sensor, which enable skeletal tracking of the pedestrian walking on rigid or flexible structures. Experiments were performed using a mobile platform with the time-of-flight commercial camera Microsoft Kinect for Windows 2.0. The velocity of the mobile platform is set to maintain a 1 m separation from the pedestrian in order to provide high resolution. The results of the measurement technique allowed the identification of the human’s CoM trajectory. The results of the model updating process present the probability density function of the parameters which could be used for modeling the CoM’s trajectory of the pedestrian. Keywords Human-structure interaction • Pedestrian’s trajectory • Human-induced vibrations • MS kinect sensor 20.1 Introduction After an incident related to excessive oscillations which occurred in 2000 on the opening day of the Millennium Bridge in London, researchers and engineers started to pay more attention to the phenomenon called Human-Structure Interaction (HSI). Since that time a number of papers have been published introducing a variety of mathematical models of this phenomenon. However, there is still insufficient understanding of the physics which is behind the phenomenon and governs this interaction [1, 2]. This paper presents an experimental verification of the model described earlier by Blachowski et al. [3]. The essential part of this model relies on the accurate knowledge of the trajectory of the pedestrian’s center of mass (CoM). This work is a first step in a bigger project which is intended to develop a better understanding of the influence of a vibrating structure on the movement of pedestrians on it. Here, we focus on the experimental part and selection of a feasible measurement technique which would allow to identify the pedestrian’s CoM during walking on a rigid surface. There is a rich literature related to experimental human movement analysis, in which authors suggest different measurement systems for that purpose. One of the pioneering works in that field is a book by Braune and Fisher [4]. The Authors begun their original research at the end of the nineteenth century and used a technique called two-sided chronophotography. This technique requires two cameras to be opened and shut at short intervals at precisely the same time. To illuminate different parts of the human body the Authors used tubes, which were filled with rarefied nitrogen. Modern techniques for measuring human movement can be classified as either motion capture using optoelectronic cameras or inertial motion tracking using a set of accelerometers. The work by Whittle [5] belongs to the first class of A.R. Ortiz ( ) Department of Civil and Environmental Engineering, Universidad del Norte, Barranquilla, Colombia e-mail: oalbert@uninorte.edu.co B. Blachowski • P. Holobut Institute of Fundamental Technological Research, Polish Academy of Sciences, Warsaw, Poland e-mail: bblach@ippt.pan.pl; pholob@ippt.pan.pl J.M. Franco • J. Marulanda • P. Thomson School of Civil Engineering and Geomatics, Universidad del Valle, Cali, Colombia e-mail: jean.franco@correounivalle.edu.co; johannio.marulanda@correounivalle.edu.co; peter.thomson@correounivalle.edu.co © The Society for Experimental Mechanics, Inc. 2017 J. Caicedo, S. Pakzad (eds.), Dynamics of Civil Structures, Volume 2, Conference Proceedings of the Society for Experimental Mechanics Series, DOI 10.1007/978-3-319-54777-0_20 159
RkJQdWJsaXNoZXIy MTMzNzEzMQ==