Xiaojing Li

In this paper, an adaptive fixed/arbitrary‐time distributed cooperative guidance law is proposed to solve the three‐dimensional simultaneous attack problem. Firstly, with undirected topologies, a second‐order leader‐following consensus protocol, integral sliding mode, and adaptive law are implemented to construct an adaptive fixed‐time cooperative control law for intercepting a maneuvering target. Range‐to‐go is chosen as the consensus variable instead of time‐to‐go, and simultaneous arrival of multiple missiles is achieved for the incoming target despite the variations in velocity magnitude. Meanwhile, a robust fast fixed‐time observer is designed to estimate target accelerations, and an arbitrary‐time sliding mode manifold is constructed and maintained across the entire time domain, while a continuous adaptive sliding mode control law is formulated through synergistic integration of adaptation law and quasiswitching function. The settling time of the closed‐loop guidance system can be precisely chosen by a predetermined time constant, and LOS angular rates can be effectively steered to the equilibrium point. By relying on the position and velocity of the incoming target, normal acceleration and longitudinal acceleration can achieve a simultaneous hit‐to‐kill attack with the desired impact angles, while fast fixed/arbitrary‐time stability is proved through the Lyapunov theory. Finally, numerical simulations are performed to validate the feasibility and effectiveness of the theoretical results.

For the guidance problem of multiple missiles cooperatively intercepting a maneuvering target, fixed-time cooperative guidance law is proposed with impact angle constraints. First, fixed-time consensus, integral sliding mode technique, and adaptive super-twisting algorithm are implemented to construct cooperative guidance law along the line-of-sight (LOS) direction. Second, based on fixed-time convergence observer and terminal sliding mode control, one fixed-time guidance law along the normal direction of LOS is designed to ensure that the missiles attack the target with expected angles. Finally, simulation results are carried out to demonstrate the effectiveness of the proposed fixed-time cooperative guidance law.

This paper investigates continuous anti-saturation three-dimensional guidance law against maneuvering target at the desired line-of-sight (LOS) angles. Firstly, in the light of fixed-time stability, fast nonsingular terminal sliding mode is designed without the limitation of odd-ratio fractional order. Then, with the limits of lateral acceleration saturation, continuous guidance law is proposed to guarantee that desired LOS angles are reached and maintained after the specified time, while adaptive law is implemented to estimate the information on maneuver accelerations of the attacking missile. Finally, numerical simulations are presented to validate the effectiveness and rationality of the designed scheme.