Adaptive Nonsingular Fast Terminal Second-order Sliding Mode Guidance Law

Abstract

Aiming at the terminal guidance with impact angle constraint against maneuvering targets, a guidance law with impact angle constraint was proposed. Based on the relative motion model of the missile and target, the impact angle constraint was transformed into the terminal line of sight(LOS)angle constraint. A new nonsingular fast terminal sliding-mode-surface was designed. Combined with the improved super-twisting algorithm, an adaptive nonsingular fast terminal second-order sliding-mode guidance law was proposed. The guidance law can make the LOS angle and LOS angular rate converge in finite-time, and a parameter adaptive-law was designed to effectively compensate the unknown disturbance. The simulation results indicate that by the proposed guidance law, the target can be accurately intercepted with expected impact angle. Compared with the existing guidance laws, the proposed guidance law has faster convergence speed, higher guidance precision and less energy consumption.