Frequency domain identification of the active 3D mechanical structure for the vibration control system

Nowadays structures are light and compliance therefore such structures are opened to the influence of external and internal excitations which in results lead to the structure vibrations and cause a loss of the energy which is used in the process realized by the structure. For example: arms, antennas, satellite solar batteries or slender skyscrapers are such plants. To damp the vibrations and save loss energy we develop design the active vibration control systems. To design such control system we should realized very important stages beginning from analytical investigations through process identification of the dynamical system. The 3D bar structure with sticked parallel piezo-stacks into chosen bars is considered in the paper. Piezo-elements play a role of piezo-actuators, while two eddy-current sensors located in free plane the structure are used to measurement displacement in directions X and Y. Such control plane will be considered as a two input and two output (TITO) system. As a result of analytical and numerical investigations such system was divided to two single input single output (SISO) subsystems. Such the coupled system was used in the process of the full model identification. The chirp signal was applied in identification process. The structure was excited according to single input single output controlling force while outputs signals were measured in perpendicular direction X and Y. In such way we have confirmed that for control purposes the plant can be decupled.