Applying quantitative feedback theory (QFT) to designing controller for flexible flight vehicle

The introduction of the full paper reviews Refs. 1 through 3 and then proposes applying QFT to designing controller. Sections 1 and 2 explain our controller design method, which is illustrated by taking a certain type of flexible flight vehicle as example. Their core consists of: (1) we employ the balanced truncation reduction method to reduce the number of orders of the flexible flight vehicle model from 12 orders to 6; (2) the 6-order model approaches the performance of its full-order model in a wide frequency band range; (3) using the reduced-order model, we apply the QFT to designing the longitudinal altitude-holding controller, which is directly used to control the 12-order model of flexible flight vehicle. Section 3 simulates our design method; the simulation results, presented in Figs. 5, 6 and 7, and their analysis show preliminarily that: (1) the command signals of the controller thus designed can be tracked quickly by its altitude response without steady-state error not only in normal state but also in system matrix perturbed state; (2) the tuning time is about 7s; (3) the elastic structure transform modals of all orders can be restrained quickly and become zero finally.