DOI: 10.35097/vfrrc2hbxkujanz8
title: Measurements of the Mechanical Impedance and Vibration Power Absorption for Varying Grip and Push Forces for Rotatory Excitation around the zh-Axis

description: The data set contains the raw as well as the evaluated data from a subject study with 6 subjects to measure the mechanical impedance and the vibration power absorbtion while varying the grip and push forces in four levels between 25-135N and 30-100N respectively. For each subject 10 additional measurements at random grip and push force combinations were recorded for validation purposes. The subjects were randomised to hold the force levels while the measurement handle was excitated around the lower arm axis (zh-axis according to DIN5349:2001) to their hand-arm system via a shaker system, with the posture of the subjects lying within the ranges specified in ISO 10819:2022. The measuring handle on which the study was conducted complies with the specifications in ISO10068:2012 for translatory excitations. To calibrate the handle for rotational excitation, a calibration function was calculated by exciting the handle with different weights. The excitation was a multisine with frequencies between 10 to 500 Hz in 5 Hz increments. Between 10 to 30Hz the amplitude of the multisines angular acceleration in the frequency domain are linearly increased from 20 to 100rad/s². From 30 to 500Hz to amplitude of the angular acceleration is at each frequency of the multisine 100rad/s². The acquisition time of each measurement is 16.5 sec, for the evaluation the data is cutted to exclude the first 2 sec and the last 3.5 sec.
The data set for translatory excitation in zh-direction is published as: DOI: 10.35097/uwz0qdyzh8h8uekw KITopen-ID: 1000181216
description: The data set consists of five types.
1) In table AnthroDemoMaxForcesTable.mat the anthropometric data, the gender and the maximum grip and push forces of the subjects are listed.
2) In Matrix resultsMatrix.mat the mechanical impedance and the phase angle of the measurements of the subjects study are summarized. The resulting mechanical impedance and the phase angle are already calibrated in each direction, and can be used directly from the matrix. The matrix consists of two dimensions, the first is the mechanical impedance and the phase angle around the direction of excitation (zh), the second dimension is the cross-axial mechanical impedance and the phase angle around xh-direction. The directions are named according to the coordinate system of DIN 5349:2001. Each row of the matrix represents one measurement. The following data information and results are in the corresponding columns:

 1: number of the subect
 2: is 0 if the grip and push forces during the measurements are within the range of 5N and 14%, otherwise a 1 is at this position. This can be used for data exclusion.
 3: predefined push force value
 4: predefined grip force value
 5: experiment number according to the resultsMatrix for each subject
 6: sequence of the taken measurements of each subject, due to a randomized test plan
 7: mean measured grip force
 8: median measured grip force
 9: standard deviation of the measured grip force
 10: mean measured push force
 11: median measured push force
 12: standard deviation of the measured push force
 13: mechanical impedance at 10 Hz
 14: phase angle at 10 Hz
 15: mechanical impedance at 15 Hz
 16: phase angle at 15 Hz
 13:2:209 mechanical impedance between 10-500 Hz in 5 Hz steps
 14:2:210 phase angle of the mechanical impedance between 10-500 Hz in 5 Hz steps
 3) The VPAmatrix.mat is according to resultsMatrix.mat, instead of the mechanical impedance in positions 13:2:209 the vibration power absorption values are listed. Here, only the direction of excitation is evaluated.
 4) Raw data, the data name consists of the time stamp and is named afterwards in the same order as the matrix: Px, where x is the number of the subject, followed by the push and then the grip force and the position in the matrix. In each struct the metadata, the time and the signals are saved. The excitation in the subject study was applied around the forearm axis (zh according to DIN5349:2001). Therefore, the angular_acceleration_z is already calculated from the recorded sensor signals az_top and az_bottom (the acceleration at the top and bottom of the measuring handle) in excitation direction. Torque_around_z is the torque resulting from the force sensor signals Fz_top and Fz_bottom around the direction of excitation. Torque_around_z and the angular_acceleration_z are used to calculate the mechanical impedance and vibration power absorption around the excitation direction (dimension 1 in the resultsMatrix.mat file). The signals used for the second dimension of the resultsMatrix are Torque_around_x (resulting from Fx_top, Fx_bottom) and angular_acceleration_z. The raw data includes the measurements of 16 levels of grip and push force combinations with three repetitions for each subject, as well as additionally measured validation data at random intermediate force levels. 
 5) emptyMeasurement.mat is a measurement of the unloaded handle while excited with the same signal as in the subject study. This file can be used for the calibration of the handle.