Active vibration control of a car body based on experimentally evaluated modal parameters

Active vibration control has been successfully tested for structures with s imple geometry, such as beams and plates, by using modal controllers. Since the dynamical behaviour of a variety of mechanical structures can be expre ssed in terms of modal parameters, the application of modal control concept s can be extended to structures with more complex geometries. For such stru ctures the evaluation of modal parameters from numerical calculations of lo cal modes is complicated because the results strongly depend on proper boun dary conditions of the truncated structure. Therefore, the modal data are i dentified by an experimental modal analysis. The transformation of the expe rimentally evaluated mode shapes into a closed analytical formulation and t he extraction of modal input and output factors for sensors and actuators c onnect experimental modal analysis and modal control theory. The implementa tion of the input and output factors into a modal state-space formulation r esults in a modal filter for the point sensor array and a retransformation filter for the segmented actuator patches. In this study, PVDF foil is used for sensors and actuators. The modal controller is implemented on a digita l controller board and experimental tests with the floor panel and centre p anel of a car body are carried out to validate the proposed concept. (C) 20 01 Academic Press.