The Transient Control Research On The UVA Speed And Attitude Angle

In the flight control system, the direct impact on plane’s flight safety and the effectiveness of completing the mission comes from its transient response and steady-state response to an external command signal. However, because of the features that flight control system model is higher-order and nonlinear, there are some difficulty to analysis the transient response characteristics and control effectively for each the UVA flight speed and pitch angle. Therefore, the UAV flight speed and pitch angle transient control problem is proposed, this thesis researches the problem of the transient response analysis and control of the flight control system with high-order, multi-input multi-output and nonlinear characteristics by means of global coordinate transformation, nonlinear system control technology.Specifically, the research achievements of the thesis are as follows.1. Some key characteristics of full-order(6-DOF) kinematics and dynamics model of fixed-wing aircraft, including the high-order property and nonlinearities, are analyzed. Under some assumptions, two simplified models are developed for deriving velocity and pitch angle tracking controllers. One is the decoupled linearized model, where the velocity dynamics and the pitch-angle dynamics are described by a third-order chain of integrators and a fourth-order chain of integrators, respectively. The other is the coupled nonlinear model with two inputs and two outputs.2. A transient control algorithm of the UAV speed/pitch angle based on SISO integral chain model is bring forward. It can ensure that the output is tracking the reference signal monotonously and without overshoots.3. A transient control algorithm of speed and pitch angle based on DIDO nonlinear model is proposed. There are two different methods to analysis the multi-variable nonlinear system. On one hand, the nonlinear system is processed into multi-variable linear model which can be controlled with linear control law by small perturbation linearization method. On the other hand, a nonlinear control law is proposed by some control technology such as global coordinate transformation, feedback linearization. And the ultimate goal is to ensure the output of UAV nonlinear system which uses the speed and pitch angle as control variables track the reference signal monotonously and without overshoots.4. The Simulation Platform of the UAV is established based on the Matlab/Simulink software and the algorithm can be verified. The simulation results confirm the correctness and reliability of the algorithm in this thesis. Furthermore, in order to show the advantages of the proposed algorithms, comparative analysis of algorithms is proposed.