Suboptimal Controllers For Reduction Of Vibration And Sound Radiation

Vibration control of flexible structures is an important issue in many engineering applications. As large lightweight structures used in the aeronautical and space fields are characterized by modal frequencies and damping ratios relatively low they are widely affected by vibrations that may cause problems both in terms of safety and comfort. Structural vibration can cause structure-borne noise to the structure which is especially critical to aerospace structure and underwater vehicle such as commercial aircraft or submarine system.The transmission of acoustic noise is one of the main issues and the improvement of the flight comfort trying to reduce radiated noise produced by the vibrating structures of the airplane represents an important challenge in civil aeronautics. Therefore to comply with the request of vibration suppression and noise attenuation the concept of actively controlled structures with sensors and actuators has to be introduced. In recent years several studies have been conducted on active control both using piezoelectric and inertial actuators .