Active Control System of Floor Impact Noise by Using Piezo-electric Actuators

This paper proposes a brand new active control panel system for reducing the floor impact noise, which is a main object of interest by residents in condominium in Japan. The active control of floor impact noise is realized by covering whole area of ceiling with the active panels of modular type, each of which insulates independently the impact sound emitted from the concrete slab structure. The active panel of 0.9 [m] ×0.9 [m] in dimension is comprised of light-weighted panel of honey-comb structure, five piezoelectric actuators and five acceleration sensors. A new actuator mechanism is developed, which has heterogeneous structure of piezo-electric element of bimorph type and soft plates of same size for mechanical reinforcement, and provides with the maximized displacement. The active control system reduces effectively vibrations in the panel, which are transmitted through support structures of the five actuators and excited by emitted sound wave from the ceiling surface of concrete slab structure. The system works as the robust feedback control system for rejecting the disturbance in the panel detected with the acceleration sensors. The result of the control experiment proved the effectiveness of the control system showing 6 [dB] reductions of the acceleration in the major vibration modes of the plate.