Sensor fault-tolerance control of a flexible air-breathing hypersonic flight vehicle

This paper is devoted to the controller design for a flexible air-breathing hypersonic flight vehicle (FAHFV) with sensor fault-tolerance. The curve-fit model of the FAHFV developed by Sigthorsson introduces strong bilateral coupling between the rigid and flexible modes. The flexible modes not only influence the aerodynamic forces and moments directly, but also creat unexpected sensor measurement fault, especially for the additive turbulence for angle-of-attack measurement which brings great challenge for controller design. Thus, in order to solve this problem, firstly, we establish a linear model by the using small-perturbation method around the given trim condition. Secondly, a PI observer is introduced to reconfigure all the states without static error on the basis of the system inputs and contaminated outputs. Finally, a guarantee cost controller based on the reconfigured states feedback is designed to make the FAHFV stabilized and make the given quadratic performance index function get to its least upper boundary. What contributes is that we successfully ameliorate the traditional state feedback method and eliminate the effects of sensor fault caused by flexible modes which is of great significance in actual engineering. Some simulation results show that the PI observer achieves good transient performance and the guarantee cost controller successfully makes the altitude and the velocity of the FAHFV track the reference trajectory excellently.