A Harmonic Synchronous Identification-Updating Method for Active Control of Helicopter Structural Response Driven by Piezoelectric Stack Actuators

Active control of structural response has been considered to be one of the most practical and effective technologies of active vibration control of a helicopter. In this paper, the authors present a harmonic synchronous identification-updating (HSIU) method for active control of helicopter structural response driven by piezoelectric stack actuators. The identification method for the harmonic coefficients of controlled responses is established based on the recursive least-squares algorithm, whereas the updating method for the harmonic coefficients of control inputs is established using the steepest gradient based adaptive harmonic control algorithm. By using the HSIU method, an experimental control system for a free-free beam structure driven by piezoelectric stack actuators has been established. The numerical simulations for active vibration control of a simplified airframe model and the experimental investigations on active vibration control of a free-free beam structure driven by piezoelectric stack actuators have indicated that the active control of helicopter structural response by using the HSIU method combined with piezoelectric stack actuators can reduce airframe vibration levels by more than 97% for simulation excitations and more than 75% for vibration responses measured in a Z11 helicopter and enhances convergence and robustness.