Performance analysis of active control systems based on the source-sink flow relationship of the structural intensity

The mechanisms of feedforward and feedback methods were analyzed for active vibration control. A feedforward controller was designed in the frequency domain using optimal control theory. The feedback control uses the direct velocity feedback method. The two control methods were applied to a plate, and the mechanisms were analyzed by examining the structural intensity map. In the case of the feedback system, the disturbance acting on the structure serves as a source, and the control force acts as a sink to reduce the vibration energy of the structure. On the other hand, in the feedforward system, the energy is reduced by the destructive interference of the intensity generated by the disturbance and control force. In this case, when analyzing the vibration intensity of the structure, component by component, the intensity generated by the control force is interfered with mainly the mutual power terms. They are the product of the force due to disturbance and the velocity due to control force, vice versa. Based on this analysis under the source-sink relationship of the feedback system, we confirmed that a higher control performance can be obtained by the control force at a point where the structural intensity is in a more easily flow position. (C) 2021 Institute of Noise Control Engineering.