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In this paper, a novel composite controller design technique is addressed for using an adaptive interval type-2 fuzzy logic system (FLS) with the fixed-time disturbance observer (FTDO) such that the enhanced tracking performance is achieved for an air-breathing hypersonic vehicle with a variable geometry inlet (AHV-VGI). First, introducing the variable geometry inlet to take proper mass flow into the engine without any flow spillage ensures enough thrust for acceleration and maneuvering flight. The interval type-2 FLS integrated with an adaptive control algorithm is derived to approximate the complicated nonlinear items in the control strategy online, which assures that the tracking error are semi-globally uniformly bounded. After that, the fixed-time disturbance observer that is constructed to provide the estimations of uncertainty including external disturbance leads to a more practical and robust flight control system for AHV-VGI. The uniform stability of the whole system is proved under the framework of Lyapunov theory. Finally, simulation results and analysis are presented to demonstrate the effectiveness of the proposed composite control scheme.

Unmanned aerial vehicle (UAV) swarms have attracted great interests in numerous civil and military scenarios due to their flexible deployment and mobility. The increased network size poses a challenge for the network scalability. Clustering as an effective scheme, is able to provide efficient communication and network performance. In order to adapt to the change of network topology, the link subsistence probability is used to evaluate the mobility of UAVs. However, the UAVs usually perform tasks collaboratively, which leads to their movements are typically group-based. To this end, a coalition game theoretic framework is proposed to cluster UAVs into coalitions in a distributed autonomous manner, based on the group and the mobility information. The proposed game allows the UAVs with the same group, as much as possible, into one coalition under some constraints, such as cluster size and cluster diameter. To solve the game, each UAV makes its decision whether to switch based on the coalition value. Finally, some comparisons are provided to illustrate the efficiency of the proposed algorithm.

In this paper, the attitude control problem of reusable launch vehicles (RLVs) during reentry phase is investigated by using compound adaptive fuzzy H-infinity control (CAFHC) strategy in the presence of parameter uncertainties and external disturbances. Firstly, the control-oriented attitude model is established by a model transformation based on the six-degree-of-freedom (6-DoF) dynamic model of the RLV. Secondly, a novel attitude control scheme is developed and the control strategy consists of two parts to achieve a stable and accurate attitude tracking during reentry flight process. An attitude tracking controller is designed utilizing adaptive fuzzy H-infinity control approach combined with an identification model to improve the attitude tracking performance in the interior of fuzzy approximation region of attitude angle. Next, an attitude stabilization controller based on boundary adaptive technique is employed to assure the robustness of the closed-loop system in the exterior of fuzzy approximation region of attitude angle. Furthermore, the stability of the closed-loop system is guaranteed within the framework of Lyapunov theory and the attitude tracking error converges to a small neighborhood around origin. Finally, the simulation results are presented to demonstrate that the effectiveness of the proposed control scheme for reentry RLV, and its tracking performance performs better than the other control method.

This paper describes the design of attitude control for reusable launch vehicles during reentry phase using adaptive fuzzy control strategy with compensation controller that assures a stable and accurate attitude tracking despite having parameter uncertainties and external disturbances in the plant model. Firstly, the six-degrees-of-freedom dynamic model of the reusable launch vehicles is established, followed by a model transformation of rotational and kinematic dynamic equations, which results in a strict-feedback form attitude control system. Secondly, a fuzzy logic system combined with the adaptive technique is employed to model the system uncertainty term online. Then an attitude tracking controller based on adaptive fuzzy control approach is designed to assure tracking of guidance commands. Furthermore, to attenuate the adverse effects of fuzzy modeling errors on the control performance and system stability, a compensation controller is introduced to the control strategy. In addition, the stability of the closed-loop system is proved by using the Lyapunov theory, and the attitude tracking error converges to a small neighborhood of the origin. Finally, the simulation results and discussions are provided to verify the effectiveness of the proposed control strategy in tracking the guidance commands.

This paper presents a fuzzy smooth-switching coordinate strategy for air-breathing hypersonic vehicle with variable geometry scramjet inlet (AHV-VGI), which can improve the aerodynamic performance of hypersonic vehicle by moving the movable lip to capture more airflow. The longitudinal model of AHV-VGI is firstly formulated, followed by a strict feedback form model. Wherein, the multiple nonlinear aerodynamic models are established with different elongation distance of translating cowl. Secondly, a finite-time nonsingular terminal sliding mode control (NTSMC) method is introduced to develop velocity and altitude subsystem controllers for each model. After that, an interval type-2 fuzzy logic system technique is employed to guarantee the smoothness during switching process between the adjacent NTSMC controllers. Furthermore, the Lyapunov function combined with adaptive laws are constructed to prove the finite-time stability of the closed-looped switching system. Finally, simulation results are provided to validate the effectiveness of these theoretical results.

By using light-weighted material in hypersonic flight vehicle, the vehicle body can be easily deformed. The mutual couplings in aerodynamics, flexible structure and control system will result in aeroservoelasticity problem. Based on the six-DOF geometry of a hypersonic flight vehicle, this paper uses assumed modes method, Shock-Expansion theory and Piston theory to develop the structural elastic model and the aerodynamic model, with actuator incorporated, the open-loop aeroservoelastic model of a six-DOF HFV is established. In open-loop analysis, the response of the elastic coordinates to the tail rudder deflection and the frequency characteristic of the transfer function of the tail rudder deflection to the first elastic coordinate are studied. A high gain feedback controller is designed for the aeroservoelastic model, and closed-loop analysis is conducted based on this model. The simulations show the influence of the elastic motion on the aerodynamic forces and moments.

This paper develops a control method for an air-breathing hypersonic vehicle with variable geometry inlet (AHV-VGI). For the AHV-VGI, a movable translating cowl is used to track the shock on lip conditions to capture enough air mass flow, which can ensure a more powerful thrust. Compared with traditional air-breathing hypersonic vehicle with fixed geometry inlet (AHV-FGI),this AHV-VGI extends the velocity range, which is favorable to the acceleration and maneuvering flight. However, the VG causes the unknown changes of the aerodynamic forces, moment and the thrust in the meanwhile. Therefore, we firstly establish a longitudinal dynamic for AHV-VGI, which includes the uncertain changes induced by VGI. A conception of the optimal elongationdistance of translating cowl is introduced, and its estimated value is obtained by curve fitted approximation. And then, the controlprocess for AHV-VGI is divided into two subsystems. For each subsystem, a sliding mode controller is designed, and interval type-2 fuzzy logic systems (FLSs) are adopted to approximate nonlinear parts including the uncertain changes induced by VGI. Furthermore, uniformly stability of the whole system is proved by Lyapunov approach. Finally, simulation results demonstrate thatAHV have a better control performance under the condition of VGI compared to the FGI.