Active Vibration Control System for Attenuation of Structure Borne Road Noise by Tire Cavity Resonance Using Piezoelectric Stack Actuators

This paper presents the novel active vibration control (AVC) system that controls vehicle body vibration to reduce the structural borne road noise. As a result of vehicle noise testing in a test vehicle, the predominant frequency of vehicle body vibration that worsens interior noise is in the range under 500Hz. Such vibration in that frequency range, commonly masked in engine vibrations, are hard to neglect for motor driven vehicles. The vibration source of that frequency is the resonance of tire cavity mode. Resonator or absorption material has been applied inside the tire for the control of cavity noise as a passive method. They require an increment of weight and cost. Therefore, a novel method is necessary. The vibration amplified by resonance of cavity mode is transferred to the vehicle body throughout the suspension system. To reduce the vibration, AVC system is applied to the suspension mount. The AVC system consists of one actuator, two vibration sensors and one reference vibration sensor based on feed forward control and its technical validation is performed on the test rig of a car suspension system. As novel work for the successful control of the AVC system, firstly, ring-type piezoelectric stack actuator suitable for this AVC system was developed and mounted inside the suspension mount bolt. Secondly, the mount location of the reference accelerometer was selected based on the coherence method. Filter length of the adaptive filter used for the FxLMS algorithm was optimized based on concept on optimized filter length. The developed AVC system could suppress the vibration level (-6dB) caused by the tire resonance at the target frequency band. The proposed AVC system will provide a novel modality to enhance the quality of noise and vibration in motor driven vehicles by actively controlling tire-induced structural vibrations.