Abstract: The transient response and its influenee factors are investigated and a method for attenuating the transient response has been developed by means of a time vacying model.The system gain matrix is obtained by choosing the weighting matriees and solving the time varying Riccati equation. Control forces are applied to the system via a feed back loop.Comparisons of responses with control and without control are made.The results show that the transient and steady-state responses are significantly suppressed in the close loop system and control forces are very small.

Key words: vibration, rotors, active control