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TECHNOLOGIES FOR MOTOR BEHAVIOUR ANALYSIS AND VIRTUAL MODELLING July 19, 2016 EXERCISE 1 A parallelepiped-shaped force platform has a thickness of d = 4 cm and rectangular base. Four load cells, displaced as shown in Fig.1, are longitudinally spaced by a distance a equal to 60 cm and transversally spaced by b = 40 cm. Force reactions are calculated using piezoelectric sensors in quartz, having sensitivity equals to k = 2,3 pC/N. Charge ampl ifiers are used to amply the signals sensed along the different axes, as depicted in Fig. 2, providing the following output voltages: Considering a voltage supply V CC of 5V, the circuit low -frequency pole placed at f L=20Hz and the following parameters: determine: 1.1 The reaction forces exerted by the load cells linked to the voltage measures provided by the amplifiers (approximated to the nearest tenth) 1.2 Considering the reaction forces referred to the lower base of the platform, with the xz plane of the reference frame laid over the lower base and the origin of the axis placed over the second load cell (see Fig. 1), calculate the the location (xcp, ycp, zcp) of the centre of pressure cp as the intersection point between the reaction force vector R and the upper base of the platform 1.3 The location of the high-frequency pole for the sensor-amplifier circuit Figure 1. Force platform Figure2. Conditioning circuit EXERCISE 2 We want to analyze the spectrum of the EMG signal extracted from the activation of different motor plates of the same motor unit. The power of the spectrum is reported in Fig. 3. Calculate: 2.1 Mean frequency 2.2 Median frequency The canonical moments calculated from the spectrum are the following: M1=0 M2=184 M3=-826 M4=60000 2.3 Determine the type of symmetry and kurtosis of the spectrum. Figure 3.…