| Active control technology is the use of a multivariable active control systems to improve the manoeuvrability, the dynamic flight characteristics and the structural dynamic properties of an aircraft by simultaneously driving an appropriate number of control surfaces and auxiliary forces or moments in such a fashion that either the loads which the aircraft would have experienced as a result of its motion with an active control system are much reduced, or the aircraft produces a degree of manoeuvrability beyond the capability of a conventional aircraft. Gust load alleviation system is one of these active control systems. The purpose of this system is that specially located sensors provide motion signals to a controller which causes appropriate deflections of suitable control surfaces to generate additional aerodynamic forces and moments to reduce the bending moments or accelerations caused by the gusts.; In this project, a bomber aircraft B-52 equipped with a gust load alleviation control system is presented and analysed. In deriving the longitudinal equations of motion for the B-52 it was assumed that the rigid body motion of the aircraft was represented by the short period approximation. Included in both sets of equations were the dynamics associated with five structural bending modes. The control inputs which were employed for longitudinal motion were the deflections of the elevator and a horizontal canard. The vertical acceleration is measured at different aircraft locations for various types of gusts.; The generation of the vertical gust, and the optimal control system design, such as Linear Quadratic Gaussian (LQG) to prevent gust effects will be discussed for three types of gusts. It has been found that the vertical acceleration has been reduced with the gust load alleviation design. |
