System identification of structural acoustic system using the scale correction

System identification can be a nice tool to make an accurate model of structural acoustic system that can describe the structure-borne noise in a car or an airplane. However, the implementation of the system identification technique to the structural acoustic system is difficult since the system is made of different physical systems. The responses from one system of the hybrid system show different characteristics from those of the others. If we try to identify the system from the responses of different physical systems, we meet a very embarrassing situation. The scales of those signals are so different that the system identification will concentrate on the modelling of the signals with large magnitude. Scale correction process is introduced to adjust the relative magnitude of those signals. When the scale correction is applied, the responses regenerated from the identified system model are similar with the original ones, which means the identified system is correct. This method will be useful for the other hybrid systems such as the structure–control system, structure–soil system and structure–fluid system.