Improved gust alleviation method

Having failed to find any detailed technical information concerning gust alleviation of active-control large transport aircraft, Chinese engineers have to research and develop such information ourselves. In a book^[1] coauthored by the first author, such information, as available in China before 1999 and known to the first author, was included. Since 1999 we have made further improvements; we now present the improved version of such information. Our method is a dynamic asymptotic decoupling method for MIMO (multi-input multi-output) system. This method is based on output feedback, partial state feedbacks and pole assignment technology. In the full paper, we explain our method in detail; here we give only a briefing. By adjusting the controller parameters, the zeros and poles of the closed loop system are assigned to suitable positions; principal diagonal elements of the closed loop transfer function are purposefully made dominant in order to minimize the dynamic gain of the non-principal diagonal elements. So the dynamic asymptotic decoupling control for the MIMO system is accomplished. As a numerical example, we used our method to design the vertical transition mode (direct lift control) of a certain active-control aircraft for gust alleviation. Simulation results show preliminarily that, as compared with normal design, the vertical transition mode designed by our method improves the gust alleviation capability by 36%. Application of our method to gust alleviation of real aircraft remains to be done.