Datenpaket: Measurements of the Mechanical Impedance and Vibration Power Absorption for Varying Grip and Push Forces for Translatory Excitation along the yh-Axis

Understanding the interaction between the hand-arm system (HAS) and the tool supports the product development of handheld and hand-guided tools. The tool transmits vibration to the HAS, while the user's interaction, e.g. varying grip and push forces, in turn affects the tools dynamic behavior. Models of the HAS describe this interaction by predicting how the hand and arm respond to mechanical vibration. This data set provides the underlying experimental data for 10 subjects: it characterizes the dynamic response of the hand-arm system through three frequency-dependent quantities — apparent mass, mechanical impedance, and vibration power absorption — recorded while subjects maintained defined grip forces (four levels, 70–135 N) and push forces (four levels, 25–65 N) and translational vibration was applied along the handle axis (yh-axis according to DIN 5349:2001). Each force combination was repeated three times per subject, and ten further measurements per subject at randomized force combinations serve as validation data. The data set provides 2897 records from the main study and 854 validation records, each for apparent mass, mechanical impedance, and vibration power absorption.

The study was approved by the Ethics Committee of Karlsruhe Institute of Technology (no. A2025-018). Each participant gave written informed consent after receiving information on the study procedure and the handling of their data, and was free to withdraw at any time. As data on the vibration response of the female hand-arm system remain scarce in the current literature, participants were recruited to achieve an approximately balanced sex distribution.
The measurements were carried out on an instrumented handle that complies with ISO 10068:2012. Translational vibration was applied to the hand-arm system along the handle axis (yh-axis according to DIN 5349:2001) by a shaker system, while the subjects' posture remained within the ranges specified in ISO 10819:2022. Prior to the study, a calibration function for the handle was derived by exciting it with several reference weights. During acquisition, the subjects held the prescribed force levels in randomized order: grip force at four levels from 70 to 135 N and push force at four levels from 25 to 65 N. Each grip–push force combination was repeated three times per subject, and ten additional measurements at randomized force combinations within the same ranges were recorded per subject for validation purposes.
The excitation signal was a multisine covering 10 to 100 Hz in 5 Hz steps with an overall root-mean-square acceleration of 40 m/s². Between 10 and 30 Hz, the acceleration amplitude increased linearly from 2 to 6 m/s²; from 30 to 100 Hz, it was held constant at 6 m/s² at each frequency.
The three quantities characterize the dynamic response of the hand-arm system in the frequency domain. The apparent mass (AM) is the complex ratio of the applied dynamic force 𝐹 to the acceleration 𝑎 at the excitation point. The mechanical impedance (MI) is the complex ratio of the same force to the vibration velocity 𝑣, where 𝑣 is obtained by integrating the recorded acceleration 𝑎. From the real part of the MI together with the input acceleration, the mechanical power absorbed by the hand-arm system is determined and reported as the vibration power absorption (VPA). Each measurement was acquired over 15 s and segmented into data sets of 14 multisine repetitions with an overlap of 7 repetitions, yielding 2897 data sets from the main study and 854 validation data sets, each for apparent mass, mechanical impedance, and vibration power absorption.
The data set comprises two files: resultsMatrix.mat, containing the data sets from the main study with the 4×4 grip and push force combinations, and validationMatrix.mat, containing the data sets from the validation measurements. Both MATLAB structs (R2022b, The MathWorks, Inc., Natick, MA, USA) are organized column-wise as follows:
• Column 1, 'SubjectNumber': identifier of the subject. Subjects retained fixed identifiers across the studies in the other excitation directions, so the numbering is not consecutive with respect to the order of participation.
• Column 2, 'direction': evaluated direction of the accelerometer (ay) and the force sensor (Fy), together with the excitation type (Transl for translational).
• Column 3, 'accDir': evaluated direction of the accelerometer (1 = x, 2 = y, 3 = z).
• Column 4, 'forceDir': evaluated direction of the force sensor (1 = x, 2 = y, 3 = z).
• Column 5, 'recordFrequency': sampling frequency at which the signals were recorded.
• Column 6, 'MeanPushForce': mean push force applied during acquisition of the data set.
• Column 7, 'TargetPushForce': push force the subject was asked to maintain during acquisition.
• Column 8, 'MeanGripForce': mean grip force applied during acquisition of the data set.
• Column 9, 'TargetGripForce': grip force the subject was asked to maintain during acquisition.
• Column 10, 'Fjw': FFT of the force sensor signal in excitation direction, evaluated at the excited frequencies.
• Column 11, 'ajw': FFT of the accelerometer signal in excitation direction, evaluated at the excited frequencies.
• Column 12, 'MI': mechanical impedance as complex values; the absolute value gives the magnitude in Ns/m, the angle gives the phase in rad.
• Column 13, 'AM': apparent mass as complex values; absolute value in kg, phase angle in rad.
• Column 14, 'VPA': vibration power absorption as complex values; the absolute value yields the VPA in W.
• Column 15, 'freq_vec': frequency vector of the evaluation points in the frequency domain, derived from the measured data and matching the multisine excitation (10–100 Hz in 5 Hz steps).
• Column 16, 'MaxPushForce': push force measured for the subject at maximum voluntary contraction (MVC).
• Column 17, 'MaxGripForce': grip force measured for the subject at maximum voluntary contraction (MVC).
• Column 18, 'sex': subject sex (1 = male, 2 = female).
• Columns 19–29: anthropometric data, measured in accordance with ISO 7250-1:2017. 'handWeight' in g, 'bodyWeight' in kg; all length measures in mm.