THEORY OF FEEDFORWARD CONTROLLED SYSTEM EIGENPROPERTIES

Adaptive feedforward algorithms have be successfully applied in the active control of sound and vibration. However, the actual mechanisms of control inherent in the technique remain an area of much interest. The main objective of this research is to study the dynamic characteristics of a feedforward controlled elastic system. The structure is assumed to be subjected to a harmonic input excitation, and the resulting vibration minimized by utilizing another force for control. The controller is defined by minimizing the square of the response at a point denoted as error sensor location. A new mathematical approach to predict the dynamic characteristics of the controlled structure is presented. It is shown that the controlled system effectively behaves as having new eigenproperties. The controlled eigenvalues and eigenfunctions are function of the control force and error sensor locations, and independent of the input disturbance. Numerical examples demonstrate the applicability of the proposed formulation. These results are also corroborated experimentally using a feedforward controller implemented on a TMS320C20 DSP processor. © 1992.