Typical example of force and position data of one trial of one participant in the arm dynamics measurements.
(a,b) Time and frequency domain representation of the position input signal, as measured using Optotrak markers at the end effector of the haptic device. Only a few seconds of the time domain representations are shown. (c,d) Time and frequency domain representation of the force signal, as measured with the force sensor of the HapticMaster. (e) Squared coherence of the position and force data. (f) Frequency Response Function based on the ratio of the spectra in b and d. The dashed blue line shows the fit that was made using the mass-damper-spring model (see Equation 4). For this trial, the model yielded the following values: M = 0.554 kg, B = 6.45 Ns/m, K = 135 N/m.