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TECHNOLOGIES FOR MOTOR BEHAVIOUR ANALYSIS AND VIRTUAL MODELLING July 11, 2018 EXERCISE 1 [6/30] A force platform with four tri -axial piezoelectric transducers (1…4), suitably preloaded, is further loaded with a cylindrical mass, placed as follows (horizontal plane projection): The cylinder vibrates vertically (along the z coordinate) at a frequency of 70Hz, delivering a vibrating force to the platform as follows: F= (500 cos(2π70t)) N Consider the sum of the charge generated by the four transducers. Given a charge amplifier as the one in the figure below with C f equal to 1nF and given the force sensitivity of the tri -axial transducers equal to 2.5, 2.5 and 5pC/N along the axes x, y and z respectively, compute the maximum absolute value of the outp ut V0 resulting by the vibration of the cylinder. EXERCISE 2 [4/30] Briefly describe: 2.1 the Motor Unit Action Potential (MUAP)? What is its relation with the Interferential Electromyographic signal? 2.2 The sources of noise and distortion that can af fect the EMG signal collected and amplified by an INA. Describe, wherever exist, possible solutions. EXERCISE 3 [5/30] 3.1 If two electrodes for EMG generate two half -cell potentials of 180mV and 220 mV respectively, can this problem be tackled by using an INA amplifier with AD=1000 and voltage supply VS=±3V? 3.2 What does it happen if you do not manage to eliminate the half -cell potentials from the signal? Sketch a possible solution to the problem, dimensioning the required components in a way to preserve the relevant frequency components of the EMG signal. EXERCISE 4 [5/30] We are interested in measuring the acceleration values to which the subject’s ankle is subjected during the walk using an IMU. When linear accelerations due to ankle movements are negligible the…