Response-dependent velocity feedback control for mitigation of human-induced floorvibrations

Abstract

Previous work on active vibration control of floors has focused on direct velocity feedback(DVF) control laws with a saturation nonlinearity that aimed to ensure the actuators werenot overdriven and to level off the response in the case of unstable behaviour. Thispaper presents a novel response-dependent velocity feedback (RDVF) controllaw as a possible improvement to DVF control laws. A maximum voltage to theactuator amplifier is set and a variable gain proportional to the reciprocal of themaximum of the absolute value of a sampled signal in a fixed block of data is derived.A switching off rule is introduced to switch off the actuator once the vibrationmitigation function has been achieved, thus preventing the onset of limit cycles. Sensorand actuator dynamics are introduced and a simplified model of a laboratorystructure for analytical studies is derived, based on its first mode of vibration.Analytical and experimental studies of active vibration control with DVF and RDVFvelocity feedback control schemes are presented for harmonic, impulsive and humanwalking excitations. The reduction in response observed using RDVF technique iscomparable with optimum reductions using DVF without requiring a specific gain to beset.