Flight Attitude Control Of MAV

MAV(micro air vehicle) has the advantages of small size, lightness and concealment. By imitating the flight of birds or large insects, the airfoils of MAV can provide lift and thrust at the same time. Therefore the conventional propulsion device and some of the control devices can be omitted, the configuration can be simplified, and the weight can be lessened. In this dissertation, adaptive control, robust control, nonlinear integral feedback compensation control, variable structure control, and fuzzy logical system were introduced as study tools, by which MAV was studied as a practical plant and some high-order uncertain nonlinear systems were studied as theoretic plants. The control methods of flight attitude system of MAV and the similar nonlinear systems were studied. The main contents and results are as follows:The existing dynamic modeling results of MAV were synthesized. The effects of dynamic forces and moments on airframe, the aerodynamic forces and moments from airfoils were studied when MAV was in the process of flying. The study emphasis was laid on the analyses of aerodynamic forces and aerodynamic moments on airfoils. The dynamic and kinematic equations of centroid movement of MAV, the dynamic and kinematic equations of movement encircling the centroid of MAV, and the movement equations of airfoils were also studied. The mathematical model of flight attitude system of MAV was presented for control.The designed method of model decomposition controller was studied for a class of nonlinear systems. An adaptive compensator was designed to eliminate the parameter uncertainties, a robust compensator was designed to attenuate the disturbances and unmodeled dynamics, and a feedback compensator was developed to dominate the nominal plant. Each of the three compensators does its best, so the design process of the integrated controller is simplified and the control precision is improved. A model decomposition controller was designed for the attitude control system of MAV and the validity was verified by numerical simulation.The designed method of integral feedback compensation controller was studied for a class of nonlinear systems. The disturbance and uncertain term are separated from the system as an unknown function and their quantities are identified online and compensated in real time by an auxiliary controller. It only requires the derivative upper bound of the unknown term, and its exact information is not necessary. The real-time performance is improved effectively. An integral feedback compensation controller was designed for the attitude control system of MAV and the validity was verified by numerical simulation.The designed method of sliding mode adaptive controller was studied for a class of nonlinear systems. The uncertain parameters are approached in real time by adaptive control, the disturbance and unmodeled dynamics are reduced by robust control to a tiny bound within finite time, and the tracking error of the uncertain nonlinear system is ultimately eliminated by sliding mode control. The quivering in the control process is overcome. A sliding mode adaptive controller was designed for the attitude control system of MAV and the validity was verified by numerical simulation.The designed method of fuzzy adaptive controller was studied for a class of nonlinear systems. The uncertain parameters are approached by fuzzy adaptive control in real time and the external disturbances are eliminated by robust feedback control. The on-line computation is decreased correspondingly and the control precision is improved. A fuzzy adaptive controller was designed for the attitude control system of MAV and the validity was verified by numerical simulation. The designed results of proposed controllers were compared.