Fast Nonsingular Fixed-Time Fuzzy Fault-Tolerant Control for HFVs With Guaranteed Time-Varying Flight State Constraints

Adaptive fault‐tolerant control for a class of flexible air‐breathing hypersonic vehicles

“…Remark The fault model in () covers the case that all actuators suffer from unknown and time‐varying faults and is much more general and challenging than those in the adaptive FTC schemes [16–21, 29], because $$$ {\beta}_i $$$ [16–21, 29] is required to be constant or piecewise constant. Particularly, in (), $$$ {\beta}_i $$$ describes the partial loss of effectiveness fault, and $$$ {f}_i $$$ covers the bias fault.…”

“…The bound estimation approach brings a nice feature that our scheme needs no restriction on the variation speed of the fault parameters $$$ {\beta}_i(t) $$$ and $$$ {f}_i(t) $$$ in (). Hence, as an advantage beyond the previous studies [16–21, 29], our proposed control scheme is able to deal with general and fast time‐varying faults. On the other hand, as can be seen from (), (), (), and the proof in the next section, the rest time‐varying uncertainties $$$ {G}_i(t)\kern0.1em \left(i=1,2,3\right) $$$ in front of the control signals are compensated for by the Nussbaum function.…”

“…For safety and reliability reasons [16][17][18][19][20][21], some adaptive fault-tolerant control (FTC) schemes were proposed for the longitudinal dynamics of AHVs. Nevertheless, in previous works [16][17][18][19][20][21], the fault parameters including the additive fault and the actuation effectiveness were required to be constant or piecewise constant, while in practice they may vary with time. Based on adaptive control techniques, time-varying actuator faults of AHVs were investigated in the literature [22][23][24].…”

“…For safety and reliability reasons [16–21], some adaptive fault‐tolerant control (FTC) schemes were proposed for the longitudinal dynamics of AHVs. Nevertheless, in previous works [16–21], the fault parameters including the additive fault and the actuation effectiveness were required to be constant or piecewise constant, while in practice they may vary with time. Based on adaptive control techniques, time‐varying actuator faults of AHVs were investigated in the literature [22–24].…”

“…With these efforts, the impacts of the faults, input constraints, and flexible modes are successfully compensated for, and global stability of the closed‐loop system is ensured. By comparison, only semi‐global stability was ensured [22–32], while time‐varying actuator faults and input constraints were not addressed [1–21]. • The altitude tracking error and the velocity tracking error of the vehicle are steered into some small residual sets, which can be designated in advance.…”