Setup for the Measurement of Apparent Mass Matrix of Standing Subjects

Abstract

This paper describes a system for the measurement of the apparent mass (AM) matrix of standing subjects. The system uses two electrodynamic shakers to generate vibrations along two mutually perpendicular axes (vertical and horizontal) and allows the identification of the full AM matrix with two tests, in which the standing subject is exposed to vertical excitation combined in turn with fore-and-aft and lateral vibration. A 3-D force platform measures the forces and the torques transmitted from the vibrating platform to the feet. The force platform, set up with piezoelectric load cells, has been designed in order to obtain a measurement bandwidth of 20 Hz. The supports of different load cells are meant to minimize bending moments on the sensors and to minimize the axes crosstalk. The force platform has been calibrated with a least-squares approach, using reference masses and a dynamometric hammer. The AM uncertainty, evaluated through the experiments' repeatability and reproducibility, is lower than 3.4% along the three axes (confidence level 68%). The measurement bandwidth is 20 Hz (±2%) and the crosstalk between orthogonal axes is lower than 5%, in accordance with the design requirements

Design and Testing of a 3-DOF Robot for Studying the Human Response to Vibration

“…Moreover, when only considering the vertical axis, this machine is capable of a maximum stroke of 200 mm; the commercial shakers with similar peak forces have a maximum stroke of ±25 mm. With respect to the setup proposed by Tarabini et al [19], this machine can excite all three axes simultaneously and over a wider range of frequency, namely over 1-50 Hz, in respect to 2-20 Hz. At the moment, the machine is lacking a system to evaluate the reaction force exerted by the person subjected to the vibration on the moving platform, which will form the focus of forthcoming works.…”

“…For example, Paddan et al [11] investigated the effect of floor vibration along three axes (vertical, fore-and aft-, and horizontal) on standing subjects; however, the vibration along the different directions was not provided simultaneously. Tarabini et al [19] described a system for the measurement of the mass matrix of a standing human subject when simultaneously excited with vertical and horizontal vibration. The system able to provide multi-axial acceleration consists of two single-axis electrodynamic shakers (one for the vertical and one for the horizontal direction) connected to compliant plates, which allow movement in one horizontal direction, while being rigid in the vertical and along the other horizontal direction.…”

Experimental Evaluation of the Driving Parameters in Human–Structure Interaction

“…The input vibration of the ground to the body was reproduced by means of an electro-dynamic shaker (LDS, model V875), while the exerted PGRF wa measured through a force plate located over the shaker. For more details on the set-up refer to [42]. Each subject was placed over the dynamometric plate for the measurements Note that the dynamic contribution of the force plate was filtered out from the acquired measurements during data post-processing.…”

Effect of the Shoe Sole on the Vibration Transmitted from the Supporting Surface to the Feet

“…Tests were performed at the experimental facilities of Politecnico di Milano, Lecco, Italy [19][20][21]. The vertical vibration was generated by an electrodynamic shaker (LDS V830, maximum stroke ±25 mm) and was controlled in a closed loop by an LMS Test Lab system.…”