A novel sliding mode guidance law with impact angle constraint for maneuvering target interception

A novel missile sliding mode guidance law (SMGL) in which a missile intercepts maneuvering target is proposed, which is based on a combination of the advantages of integral sliding mode control and global sliding mode control. The relative motion equations of missile and target, in which the impact angle constraints are considered, are established within the perpendicular plane. A new nonlinear saturation function is adopted to construct an integral term in global integral sliding mode surface, and then an improved nonlinear global integral sliding mode control technique is presented, which solves the problem about system transient performance deterioration and decreases the steady state errors. It is obvious that the designed guidance law enables the missile to hit target at a desirable impact angle in finite time, and the missile to be of strong robustness during the whole interception. The missile global nonlinear integral SMGL in which the autopilot dynamics and impact angle constraints are considered is investigated by adopting dynamic surface control. It is demonstrated that all states in the closed loop system are ultimately bounded on the account of Lyapunov stability theorem. The simulation results verify the effectiveness and superiority of global nonlinear integral SMGL.