| Recently, under the stimulation of the increasing application prospect, MAV has become into an international hot topic. The non-linear flight dynamic characteristics under the condition of low Reynolds number, unsteady disturbed atmosphere, the measurement precision and reliability inside the micro system, etc make the autonomous flight control of MAV become a complicated issue which is different from the control of normal unmanned air vehicles.Actually the issue of the MAV's autonomous flight is a control problem on a non-linear, unsteady and uncertain parameters'complicated system. Aiming to the requirements of MAV autonomous flight system, this thesis focuses on building an integrative research system including the object feature analysis and control methods research. From the special general distribution design of the fixed-wing MAV, low Reynolds number analysis, non-linear dynamic characteristics analysis and research of the influence of the unsteady disturbed atmosphere, an intelligent navigation and control system is established, in order to realize the autonomous flight of the MAV. This thesis mainly includes the following contents:(1) Development of a system design framework of MAV with the autonomous flight capability based on general configuration design and aerodynamic characteristics research.Aiming to the flight features of MAV, based on the special general configuration design of MAV, and the research of aerodynamic characteristics and non-linear dynamic characteristics under low Reynolds number, combined the influence analysis of unsteady atmosphere disturbance to MAV flight, a integrated research framework is established, which applies the combined navigation technologies and intelligent flight control strategies of MAV as the key technologies, in order to build an intelligent autonomous flight system. Furthermore, the flight simulation and flight experiments are through the whole research.(2) Analysis on non-linear flight dynamic characteristics of MAV under low Reynolds numberThis thesis proposes a special general distribution design scheme, developing the wind tunnel experiments of fixed-wing MAV under low Reynolds number, combining the MAV flight experimental data identification, studying the aerodynamics model of fixed-wing MAV under low Reynolds number. This thesis proposes a dynamic damping derivative computation method for fixed-wing MAV, building the flight dynamics equations of MAV under the influence of propeller slipstream. An all-state flight dynamic characteristics analysis method based on the MAV dynamic model with all degrees of freedom has been proposed, to study the dynamic characteristics non-linear variation principle in the flight envelope of the MAV.(3) Research on MAV flight mechanics characteristics under the unsteady disturbed atmosphereThrough studying generation mechanism and expression features of all kinds of atmospheric disturbance phenomena, integrating the flight features of the MAV, several typical atmosphere disturbance models which have the outstanding influence to MAV flight have been confirmed. This thesis studies the influence of typical characteristics parameters in the wind field model, building the unsteady atmosphere disturbance wind field model which is suitable for MAV flight simulation, studying the influence of the unsteady disturbance to MAV flight characteristics, and building a MAV flight dynamics model in which the unsteady atmosphere disturbance is considered.(4) Research on the combined navigation technologies of MAV based on the multi-sensor technologyThis thesis proposes a hierarchical navigation system scheme for MAV based on combined sensor technology. A Kalman attitude filter scheme to the combined information of INS and GPS under the quaternion structure is presented. Based on the attitude estimation, an optimized extraction scheme of MAV navigation location information has been proposed based on the multi-sensor intelligent combination technology.(5) Research on the intelligent control strategies of MAV autonomous flight and stability analysisFor the aim of MAV whole track navigation, this thesis builds a hierarchical autonomous flight system design scheme based on the attitude stability in all directions of the MAV. Based on the research of MAV non-linear flight dynamic characteristics and the analysis of the factual flight data, this thesis studies the fuzzy hypersurface of the variable control parameter sets in each sub-system control of MAV autonomous flight, ensuring the operation stability of each sub-system in control in a particular state range, such as attitude, height and navigation track of MAV. This thesis applies the expert control ideas, introducing the regional knowledge, experience and techniques of the remote control flight staffs into the global arbitration organization of the whole system, which makes the system harmonized and optimized as a whole so as to realize the autonomous flight control of MAV in global stability. Aiming to the characteristics of this kind of intelligent autonomous flight control, a stability analysis of MAV autonomous flight system based on Lyapunov theory has been proposed.(6) Research on the simulation platform of MAV autonomous flight and flight experimentsDetermining the configuration of mathematical simulation platform of MAV autonomous flight, studying mathematics modeling techniques of each sub-system, analyzing the error types and modeling techniques inside the MAV system, building a real and effective 3D dynamic mathematical simulation platform of MAV autonomous flight control, analyzing the importance of the flight experiments in the design of MAV autonomous flight and studying the key technologies in MAV flight experiments, developing plentiful flight experiments to provide the necessary assistance or validation check for the design of MAV autonomous flight control. |
