Aerodynamic Parameter Identification Technology Of Closed-loop Controlled Tactical Missiles

Aerodynamic parameter identification from flight test data becomes an important component of the design and evaluation program for tactical missiles. Taking into account the demands of security and stability, flight tests of tactical missiles always proceed under the closed-loop control state. The movement modes are restrained by the flight control system in high degree. In certain cases, approximate correlation exists between the input signals (control surface deflections) and the response signals (angle of attack, angle of sideslip, angular rates, accelerations, etc.). These problems make it difficult and even impossible to identify aerodynamic parameters from the flight test data. In order to overcome the difficulties in aerodynamic parameter identification of closed-loop controlled missiles, this thesis makes a study of parameter identification algorithms and input design methods.The thesis is composed of six chapters. The first chapter is the preface of this thesis. The necessity and difficulties of aerodynamic parameter identification of closed-loop controlled tactical missiles are introduced. The history and development of identification technology at home and abroad are reviewed. At last, the main contents of this thesis are presented.The second chapter introduces maximum likelihood criterion as the parameter identification criterion of dynamic system. On the basis of this criterion, maximum likelihood estimation is also presented. With the process noises of dynamic system ignored, a more simple method, called output error method, is developed.In the third chapter, Particle Swarm Optimization (PSO) algorithm is adopted for optimization computing, to overcome many difficulties of gradient algorithms. The fundamental principle of PSO algorithm is introduced in detail, and then several advanced ones are presented. Comparing the results of 6 test functions used in optimization region, a modified PSO algorithm using dynamic inertia weight is selected.In the fourth chapter, aerodynamic parameter identification method based on PSO algorithm is presented, which is the concrete realization of maximum likelihood estimation in the dynamic system of tactical missile. At the same time, Newton-Raphson algorithm is given as a contrast. In order to validate PSO algorithm, the flight data of one tactical missile are selected to be analyzed. The results of aerodynamic parameters identification show that PSO algorithm is effective. In the fifth chapter, input signal design for closed-loop controlled tactical missiles is studied. Two input design methods for parameter estimation in the time domain and in the frequency domain are introduced one after another. Then, two examples are...