Second-Order Sliding Mode Guidance Law of a Nonsingular Fast Terminal with a Terminal Angular Constraint

Based on the nonsingular fast terminal sliding mode and the second-order sliding mode control theory, this paper proposed a finite-time sliding mode guidance law to realize the attack of ground maneuvering targets with a terminal angular constraint. First, the nonsingular fast terminal sliding mode surface is selected to improve the convergence rate of the system state. Then, the second-order sliding mode control theory is applied to suppress the chattering phenomenon effectively. Moreover, the singularity problem can be avoided directly in guidance law design. A nonhomogeneous disturbance observer is designed to estimate and compensate for the external disturbance brought by the target maneuvering information. Several sets of simulations and comparison verification show that the proposed guidance law can control the missile in attacking the target at a specified angle, and has the advantages of a fast convergence rate, a short missile flight time, consuming less energy, and a strong chatter suppression ability, which verifies the effectiveness and superiority of the proposed guidance law in this paper.