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TECHNOLOGIES FOR MOTOR BEHAVIOUR ANALYSIS AND VIRTUAL MODELLING June 28, 2016 EXERCISE 1 Assume to measure with a force platform the force reactions at the foot of a subject weighting 75 kg during walk. The data collected by the platform are: The platform is parallelepiped-shaped with a thickness d = 4 cm and rectangular base. The load cells are longitudinally spaced by a distance a equal to 60 cm and transversally spaced by b = 40 cm. All the measurements provided by the load cells refer to the lo wer base of the platform. The xz plane of the reference frame lies over the lower base, with the origin of the axis placed over second load cell (see figure). Compute: 1.1 the location (x S, y S, z S) of point S as the intersection point between the direct ion of the reaction force vector R and the sensor plane (lower base) 1.2 the location (xcp, ycp, zcp) of the center of pressure cp on the platform surface (upper base) The subject is standing on the platform, with a foot steady on the upper surface (no a cceleration acting on it) and the other in swing phase. The axis of the ankle joint is orthogonal to the sagittal plane and passes through the point with coordinates yac = 12 cm and zac = 20 cm with respect to the platform reference frame. The center of pressure cp lies on the sagittal plane as well and the mass of the foot can be considered negligible compared with the whole-body mass. 1.3 Determine the reaction forces Fy, Fz at the ankle joint and the muscular moment Ma EXERCISE 2 Considering the impedance of the skin -electrode surface as described in the schematic and assuming: 𝑅𝑑 = 500 𝐾Ω 𝑅𝑠 = 200 Ω 𝐶𝑑 = 20 𝑛𝐹 2.1 Discuss the impedance value with respect to the frequency 2.2 Considering the EMG bandwidth between 0 -500Hz, does this electrode wo rk for EMG…