Abstract: The coupled modal control of structural vibration isstudied, and a new control algorithm is presented, in which the physical meaningofthe performance index of the linear Quadratic Regulator(LQR) is very clear.Simulations for the active vibration control of a structural model are carried out.The results show that thepositions of the control points and measure points have great influence on the control.

Key words: structural vibration, active control, mode