Incremental Nonlinear Dynamic Inverse-Adaptive Sliding Mode Three-Dimensional Angle Constrained Guidance Law Design

To address the angle constrained problem of 3-D maneuvering target interception, in this article, a coupled 3-D missile–target relative motion model is proposed, and then, a nonlinear dynamic inverse-adaptive sliding mode control (NDI-ASMC) is designed. Based on NDI-ASMC, an incremental nonlinear dynamic inverse-adaptive sliding mode control (INDI-ASMC) angle constrained guidance law is proposed. With the help of the transformation matrix of the coordinate system, the model under the line-of-sight (LOS) coordinate system is transformed, and then, a missile–target relative motion model is proposed. The model does not contain lead angle terms, reducing the complexity of the model and saving computational amount. An adaptive disturbance suppression term is introduced to tackle the LOS angle constrained problem with the unknown target maneuver, based on this term and the nonlinear dynamic inverse theory, an NDI-ASMC is proposed. The aforementioned disturbance suppression term can adaptively adjust to the target maneuver and does not cause chattering. Considering that the adaptive term of NDI-ASMC increases with the increase of target maneuver, resulting in greater overload, this article designs an INDI-ASMC law that can effectively reduce the overload and increase the final destruction effect on the target. The Lyapunov theory proves the stability of the proposed guidance laws, and the simulation verifies the robustness and feasibility of the guidance laws.