ADRC And H_∞ Robust Controller Design For Large Space/Speed Range Vehicle

With the rapid development and gradual maturation of near space platform technology, more and more new conceptual aircrafts are proposed and relative research works are conducted among global military powers. Near space, full of huge military values, is leading the growth of market and advanced science and technology. This paper chooses the near-space stably-controlled re-entry vehicle which has large space/speed range as research subject and designs its attitude control system.Firstly, the traditional PID gain scheduling control method is used for design. The linearized control models of three channels are established and the coupling effects are eliminated by introducing the coordination branches. Then, active disturbance rejection control is applied in the design. The attitude loops are divided into an angle feedback outer loop together with an angular velocity feedback inner loop. After designing and adjusting the three key parts of ADRCs, the nonlinear control system is combined by the 3-3 concurrent ADRCs. Next, H∞ robust control theory is utilized. The linear models with uncertainty and uncertain perturbation bound matrixes are achieved through analyzing the flight system, while robust control lemma is taken for deriving the controller solutions in form of Riccati inequality. With the Schur complement, the controller models are converted into standardized LMI feasibility solving problem, and the complete control system is implemented with the help of Matlab LMI toolkit.At last, several simulation tests including command signal tracking response, error jamming simulation and SDOF nonlinear simulation are given. The three different control methods are compared and the pros and cons are analyzed, which demonstrates the strong control performance held by ADRC and H∞ robust control.