An adaptive reaching law based three-dimensional guidance laws for intercepting hypersonic vehicle

The interception of hypersonic vehicles is a formidable challenge due to its high speed and strong maneuverability; besides, traditional guidance methods cannot guarantee interception accuracy. To solve this problem, three-dimensional sliding mode guidance laws are proposed in this paper based on the head pursuit guidance method. The first guidance law ensures that the dynamic system converges to head pursuit guidance conditions in finite time without the knowledge of external disturbances, and can also weaken the chattering phenomenon. In practical application, the capacity of dynamic actuators is limited. Therefore, a guidance law with input saturation is proposed using the hyperbolic tangent function and auxiliary system. This method is novel in which the system can be ensured finite-time and asymptotically stable. In theory, the two guidance laws can be proved using Lyapunov stability theory. The correctness and effectiveness of the methods are verified by numerical simulations.