Application Of QFT To Flight Control System

Quantitative Feedback Theory (QFT), a robust control design theory recently-popular, is studied in this paper, and applied to design the uncertainty system. Based on a set of modes for some airplane, their controllers are designed by QFT.First of all, the QFT's study object, the design properties and the QFT process are presented. Secondly, the QFT's basic knowledge is introduced, and the performance in t-domain and ω -domain of plant with uncertainty and unknown outer disturbance, are analyzed. Thirdly, some important problems, which are solved in the QFT design process, are analyzed and studied, for example, controller structure, plant templates, performance target bounds, loop-shaping, pre-filter designing , and so on. So, design process for LTI/SISO systems and cautions are summarized, and also, basic managing thought is put forward for LTI/MIMO systems, non-least phase/instability systems, and uncertain time-varying/nonlinear systems. Fourthly, design targets are chosen for a set of modes for some airplane, corresponding templates and bounds are protracted basing on plant work frequency range, controllers and pre-filters are sequentially designed. Lastly, the work are simulating design results and validating robustness, the results show that designed control systems have good responses and robustness, and the design targets are satisfied.Based on the studying presented in this paper, the QFT control system is proved to be effective in achieving the control targets. And QFT is a very important method in project application.