Control System Design, Based On The Gain Scheduling Method Guided Bombs

In the course of the guided bomb flight, the attitude control system implements guided command and controls guided bomb steady flight. Under large-space maneuver flight conditions, guided bomb system is a highly nonlinear time-varying system, the application of gain scheduling is an ideal choose for the purpose of good performance and easy to realize in engineering. However, how to effectively use gain-scheduling approach to design attitude control system is still a challenging problem.This thesis starts from the basic concept of gain scheduling and analyzes the characteristics of several common gain scheduling methods, does research on two gain scheduling approaches to control the guided bomb's attitude.Firstly, six-degree of freedom equations set of the guided bomb are established. Under the small disturbance conditions, the differential equations are linearized to get guided bomb disturbance movement equations. Using the coefficient freezing method, dynamics coefficients and transfer functions are obtained at some feature points of the bomb with specified altitude and Mach number.Secondly, controllers are designed regarding to above feature points. Then gain scheduling controller is obtained via polynomial fitting method. The time and frequency domain analysis on the other feature points of ballistic show that the gain scheduling controller works well. A global ballistic trajectory simulation shows that gain scheduling controller is superior to the fixed parameters controller.Thirdly, a LPV gain scheduling controller is designed by state feedback H_∞control theory to guarantee the stability of the entire closed loop system. The bomb control system is put into a ploytopic expression LPV model by LPV convex decomposition technique. Then a state feedback gain for every vertex is designed, which satisfies prescribed stability requirement. A global gain scheduling controller is obtained by synthesis of the vertex controllers. The results of numerical simulation also show the method guarantees stability of the closed loop system.