Linear parameter-varying based tracking control of hypersonic flight vehicles with input saturation

This paper is concerned with Linear parameter varying based tracking control of hypersonic flight vehicles subject to parameter uncertainties, external disturbances and input saturation constraints. The overall design procedure is consisted of three parts, which includes system decomposition, model transformation, and LMI-based controller design. Specifically, the tracking problem is firstly reformulated as the robust H-infinity control for uncertain quasi-LPV error subsystems through variable decomposition and small gain theorem. Then, the tensor-product model transformation technique is used to transform the system matrices into convex polytopic forms, which has less computational load and more flexibility due to the system decomposition process. Since only the weighting functions are related to the system states, the controller can be obtained by solving finite number of LMIs corresponding the LTI vertex systems, instead of solving state-dependent Riccati equation on line at a high Hertz rate. Moreover, by defining the control gain matrix described as a convex polytopic form with the same weighting functions, the designed controller is time-varying and nonlinear. Simulation results demonstrate that the proposed control method can guarantee both good tracking and disturbances rejection performance.