Active Vibration Suppression of a Smart Beam by Using an LQG Control Algorithm

The aim of this study was to design and experimentally apply a Linear Quadratic Gaussian (LQG) controller for the active vibration suppression of a smart beam. The smart beam was a cantilever aluminum beam with eight symmetrically located surface-bonded PZT (Lead-Zirconate-Titanate) patches which were utilized both as sensor or actuator depending on their location. A group of PZT patches closed to the root of the beam was used as actuators in the bimorph configuration and a single patch was nominated as a sensor. LQG controller, which is the result of a modern state-space technique, was used in order to design a dynamic optimal regulator. The controller was expected to provide a trade-off between the regulation performance and control effort and it also took process disturbance and measurement noise into consideration. The LQG regulators of the current study were evaluated via closed loop frequency domain simulations in order to regulate the vibration level of the smart beam around zero value. For the experimental verifications, a harmonious controller was selected based on the performed trade-offs between the performance and measurement noise rejection levels. The experimentally obtained time domain responses have demonstrated that the designed controller successfully suppressed the vibration levels of the first flexural mode of the smart beam.