Modified acceleration feedback for active vibration control of aerospace structures

摘要

An acceleration feedback control method suggested in several past studies is modified to include two compensators, one first order and another second order, to separately control the closed-loop system stiffness and damping. The second order compensator has a damping ratio that is as low as that of the flexible structure in order to provide periodic vibration control. The first order compensator is used to provide the necessary damping, simultaneously. Employing two separate compensators allow us to provide stiffness and damping control in a dynamically decoupled manner. The new controller is readily applicable to a strain-based sensing and actuating approach, such as piezoelectrically controlled systems. Control gains are obtained through a stability analysis that is described in detail in the paper. The effectiveness of the controller is verified experimentally using a test setup that includes a flexible plate. The plate includes two small piezoelectric patches that are used as control actuators. Ten miniature size accelerometers are mounted on the plate for measuring plate vibrations. Two piezoelectric actuators in different positions are used for vibration control of the plate and the results are compared with the condition in which only one actuator is used. In addition, the results confirm that the new controller is able to effectively control more than one frequency simultaneously.