This article proposes a fixed-time adaptive fault-tolerant control methodology for a larger class of high-order (powers are positive odd integers) nonlinear systems subject to asymmetric time-varying state constraints and actuator faults. In contrast with the state-of-the-art control methodologies, the distinguishing features of this study lie in that: (a) high-order asymmetric time-varying tan-type barrier Lyapunov function (BLF) is devised such that the state variables can be convergent to the preassigned compact sets all the time provided their initial values remain therein, which not only preserves the constraints satisfaction, but warrants the validity of the adopted neural network approximator; (b) the proposed control design ensures the tracking errors converge to specified residual sets within fixed time and makes the size of the convergence regions of tracking errors adjustable a priori by means of a new BLF-based tuning function and a projection operator; (c) a variable-separable lemma is delicately embedded into the control design to extract the control terms in a “linear-like” fashion which not only overcomes the difficulty that virtual control signals appear in a non-affine manner, but also solves the problem of actuator faults. Comparative simulations results finally validate the effectiveness of the proposed scheme.

Implementing risk assessment is of great significance to aviation safety. At present, with the gradual assembly of large transport aircraft with troops, it has become an urgent matter to carry out reloading airdrop to achieve the desired combat purpose and effect. In this paper, the task process of reloading airdrop is described in detail, the risk evaluation index system is established by using the questionnaire, and the probability and severity of the evaluation index are scored, and the risk grade is determined according to the risk matrix. Finally, the fuzzy analytic hierarchy process is used for risk assessment, and the corresponding preventive measures are put forward. The evaluation results show that in the process of heavy load airdrop, attention should be paid to the possibility of aircraft instability during the process of equipment and materials delivery.