Active aeroelastic output feedback control with partial measurements by the method of receptances

Abstract

The method of receptances allows the design of active aeroelastic control for suppressing the flutter instabilities and for augmenting the flutter boundaries by pole placement. This method is purely based on available receptance transfer functions, which can be available for controller design from the embedded sensors and actuators on the aircraft. In recent years, receptance based single-input and multiple-input full state feedback control has been developed, which requires the displacement and velocity measurements associated with each degree of freedom, which may not be available in practice. The design of a controller using partially available measurements in these scenarios is related to the static output feedback design, which leads to the solution of associated nonlinear problems and/or the design of complimentary state estimators or observers. In order to overcome such restrictions, in this paper a method for feedback control design using the receptance method is presented which can utilize the available partial measurements for control gain computation. This is achieved by introducing redundancy of acceleration measurement and adding associated acceleration feedback in the controller loop. This leads to a linear constrained least-square problem for the design of the controller. The working of this approach is shown with numerical examples associated with various wing models. It is demonstrated that prescribed aeroelastic modes can be controlled to achieve flutter suppression and flutter boundary extension, by designing a feedback controller using partial measurements from the available sensors. Parametric studies are presented to demonstrate that such output feedback control allows the optimal selection of measurements and the corresponding sensor location to minimize the controller norm.