No abstract

No abstract

This paper proposes a novel fixed-time adaptive general type-2 fuzzy logical control (FAGT2FLC) scheme for an air-breathing hypersonic vehicle (AHV) with uncertainties. Firstly, the AHV dynamic model is transformed into a strict feedback form. Then, the FAGT2FLC is designed based on the transformed model to improve robustness and guarantee fixed-time convergence of the closed-loop system. The general type-2 fuzzy logic system (GT2FLS) is utilized to approximate the model uncertainties; for the purpose of designing adaptive laws, the [Formula: see text]-plane method is employed to represent the GT2FLS. A parameter projection operator is used to solve the possible singularity problem of parameter adaption. Besides, a fixed-time differentiator is used to deal with the “explosion of terms” inherent in backstepping method. Theoretical analysis based on relevant lemmas shows that the closed-loop system will converge into a small error band in fixed time. Lastly, detailed simulations are carried out to demonstrate the effectiveness and superiority of the proposed control scheme.

This article develops a distributed adaptive fault-tolerant formation control scheme for the multiple unmanned aerial vehicles to counteract actuator faults and intermittent communication interrupt, where the issues on control input saturation and mismatched uncertainties are also addressed. The discontinuous communication protocol technique is exploited to achieve the stability of the formation system, if the conditions of dwell time and the rate of communication are satisfied. On the basis of the local information of neighboring unmanned aerial vehicles, a novel distributed adaptive mechanism is designed to estimate the bounds of actuator faults and uncertainties, where the input saturation is explicitly taken into consideration. The stability of the whole formation system under the designed fault-tolerant formation control strategy is analyzed using the Lyapunov approach. Finally, simulation results are presented to illustrate the effectiveness of the proposed scheme.

The increase in risk prevention investments in the port-hinterland service network (PHSN) effectively enhances the network’s ability to resist risks and improve the sustainability and stability of ocean transportation. Based on the construction of the PHSN risk prevention investment utility model, the equilibrium strategy, the related characteristics of each participant in the complementary networks and the complete network are analyzed. Similarly, the subsidy policy of the government under the utility maximization of the whole service network is studied. We further propose new types of subsidy strategies based on the key nodes and key groups given the resources available and the subsidy efficiency constraints imposed, while also validating the advantages of this method based on a case analysis. The results indicate that the (1) equilibrium risk prevention investment is closely related to the Katz-Bonacich centrality, network interaction intensity, cost of unit risk prevention investment and competition intensity; (2) an undifferentiated subsidy strategy cannot improve the risk prevention effectiveness of the whole network; (3) the subsidy strategy based on key nodes and key groups effectively improves the risk prevention efficiency; and (4) the subsidy strategy of key groups is superior to the subsidy strategy of key nodes. Accordingly, the results of this study provide a reference for participants and managers in the PHSN when making risk prevention investment decisions.