Further Steps Towards the Tuning of Inertial Controllers for Broadband-Frequency-Varying Structures

Abstract

There is a large number of slender structures which are prone to vibrate due to pedestrian loads. The well-known Tuned Mass Damper (TMD) is increasingly used in practice, but this device may detune under several circumstances drastically reducing its expected performance. A Semi-active TMD (STMD) provides more robustness under structure uncertainties than the passive one and may be recommended for use when several vibration modes are in the excitation range and/or when the mode to cancel has uncertainty or varies over time. The tuning of the semi-active device for these cases cannot be the same as the passive one. This paper presents a methodology for the tuning of an STMD under broad frequency-band uncertainties using an ON/OFF phase control law. This control law is experimentally implemented considering interesting practical aspects, such as the estimation of the inertial mass velocity from the measured acceleration, or a low-pass filter to avoid unnecessary control actions, among others. An optimization process using a proposed performance index is carried out. Thus, it has been demonstrated that the optimal STMD is achieved for much lower damping and higher tuned frequency than the passive one. Finally, the proposed methodology is validated with experimental results.