Active Vibration Control of Road Noise Path Using Piezoelectric Stack Actuators and Filtered-X LMS Algorithm for Electric Vehicle Applications 2024-01-2953

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 an electric vehicle, the predominant frequency of vehicle body vibration that worsens interior noise is in the range of 150-250Hz. Such vibration in that frequency range, commonly masked in engine vibrations, are hard to neglect for electric 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 two actuators, 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 actuators suitable for this AVC system were 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 order filter.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 electric vehicles by actively controlling tire-induced structural vibrations.