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TECHNOLOGIES FOR MOTOR BEHAVIOUR ANALYSIS AND VIRTUAL MODELLING June -, 20- EXERCISE 1 [7/32] A parallelepiped-shaped force platform has a thickness of d=5cm and a rectangular base. Four load cells, displaced as shown in Figure 1a, are longitudinally spaced by a distance a = 60 [𝑐𝑚] and transversally spaced by b=40 [𝑐𝑚]. Question 1.1 [3 pts]; A person is standing steady on the surface (Figure 1a). The data collected by the platform, as follows: 𝑅1 = 280𝑁 𝑅2 = 160𝑁 𝑅3 = 160𝑁 𝑅4 = 240𝑁 Suppose that, a person is so steady that the component along the x and z axes can be considered negligible. Calculate the location (𝑥𝑐𝑝, 𝑦𝑐𝑝, 𝑧𝑐𝑝) of the center of pressure 𝑐𝑝 sensed by the platform. Question 1.2 [4 pts]; Consider the following case: person standing on the plate, now starting to run as shown in Figure 1b. Measured data by the platform are: 𝑅1,𝑦 = 210𝑁 𝑅2,𝑦 = 180𝑁 𝑅3,𝑦 = 210𝑁 𝑅4,𝑦 = 240𝑁 𝑅1,𝑥 = 𝑅4,𝑥 = 80𝑁 𝑅2,𝑥 = 𝑅3,𝑥 = 40𝑁 𝑅1,𝑧 = 𝑅2,𝑧 = 20𝑁 𝑅3,𝑧 = 𝑅4,𝑧 = 40𝑁 As expected, for this case, also components along the x and z axes are observable. All the reaction forces refer to the lower base of the platform, with the 𝑥𝑧 plane of the reference frame laid over the lower base. Determine the location (𝑥𝑐𝑝, 𝑦𝑐𝑝, 𝑧𝑐𝑝) of the centre of pressure 𝑐𝑝 as the intersection point between the reaction force vector R and the upper surface of the platform. Figure 1a Figure 1b EXERCISE 2 [4/32] An EMG signal acquisition is performed at the lower limbs of a subject during a normal walk. In Figure 2, the EMG signal of the right hamstring muscle is presented in a time window of 7 secs while in Figure 3, the power spectral density is presented. Question 2.1 [1 pts] ; Highlight the muscle activation over time in Fig ure 2 and highlight the corresponding frequency components related to muscle…