EFFECTIVENESS OF THE PID CONTROL TO MR DAMPERS ON THE SEMI ACTIVE CONTROL OF BRIDGES

Response delay of MR fluid results in distortion of the control force of MR dampers. This results in problems when we use MR dampers as variable dampers. To mitigate the time delay of MR dampers, the PID Control was used. Overshoot termination control (OTC control) and 2-step PID Contol were proposed. A series of cyclic loading test for a Lord Corporation MR damper and a shaking table test of a model bridge with the MR damper were conducted to verify the effectiveness of the PID control. It was found that the PID control is effective to mitigate the time lag for friction control.