This paper proposes an Incremental Nonlinear Dynamic Inverse (INDI) control scheme for the problem of transition mode control of Tilt Rotor Unmanned Aerial Vehicle (TRUAV). Firstly, based on the dynamic characteristics of the quadrotor TRUAV, a longitudinal motion model suitable for control is established. Then, the virtual control command and control allocation methods are studied, and an adaptive tilt scheme for the transition mode of the TRUAV is designed based on these methods. Subsequently, based on the incremental nonlinear dynamic inverse control theory, the inner/outer loop controllers for the altitude, velocity and attitude transition modes are designed, as well as a mixed control method for rotor and rudder deflection control quantities. Finally, simulation experiments validate the effectiveness of the adaptive tilt scheme based on virtual control command allocation, as well as the robustness of the altitude, velocity, and attitude controllers.

In air combat, one effective way to counter an incoming missile attacking an aircraft is to launch a defense missile compared with traditional passive defense strategies such as decoy and electronic countermeasures. To address this issue, this paper proposes a three-body cooperative active defense guidance law with overload constraints from the perspective of a small speed ratio. First, a cooperative guidance-oriented model for active defense is established and linearized to provide a foundation for the design of the guidance law. Then, the essential quantity known as Zero-Effort-Miss (ZEM) is analyzed during the engagement process. In order to minimize the influence of inaccurate estimates of remaining flight time in the ZEM, the concept of Zero-Effort-Velocity (ZEV) is introduced. Subsequently, utilizing the sliding mode control method, the guidance law is designed by selecting the ZEM and ZEV as sliding mode surfaces, combined with the fast power reaching law, and its finite-time stability is analyzed using the Lyapunov method. Furthermore, to quantitatively evaluate the performance of the proposed active defense guidance law, the interception rendezvous angle index is introduced. The proposed active defense guidance law considers integrating information from the incoming missile, aircraft, and defense missile with fewer simplifications and assumptions, and ensures that the aircraft is effectively protected with less overload required for the defense missile. Finally, simulation experiments demonstrate the effectiveness and adaptability of the proposed active defense guidance law.
Under hypersonic flight conditions, the residence time of fuel in the scramjet combustor is extremely short, while sufficient mixing, ignition, and stable combustion of fuel and oxidants are important issues for hypersonic propulsion. To improve the mixing and combustion performance of fuel in the combustion chamber, domestic and foreign researchers have introduced mixing and combustion stabilization devices such as struts, ramps, cavities, and backward steps into the combustor, and have obtained certain achievements. In previous studies, the recirculating zone formed by the strut and cavity in the flow field can achieve good mixing and combustion stabilization performance, receiving widespread attention and expansion. This paper reviews the recent research progress on strut, cavity, and strut-cavity combination configurations around the world, and explores the future development direction of related research.