Three-Dimensional Adaptive Sliding Mode Guidance Law Based On Finite Time Prescribed Performance

To address the guidance problem of intercepting maneuvering targets with desired terminal impact angles, this paper proposes a three-dimensional adaptive sliding mode guidance law based on finite time prescribed performance control. First, maneuvering target interception problem is transformed into a second-order line-of-sight (LOS) angle system control problem using a projectile-target relative motion model. Subsequently, a novel finite-time convergent prescribed performance function (FPPF) is developed to overcome the infinite convergence time limitation inherent in traditional exponential-type performance functions. By constraining the LOS angle tracking error within predefined performance boundaries through the prescribed performance mechanism, a three-dimensional sliding mode guidance law is systematically designed. An adaptive estimation scheme is integrated to achieve online compensation for external disturbances. The closed-loop system stability is rigorously proven through Lyapunov stability analysis. Numerical simulations demonstrate that the proposed guidance law not only ensures superior steady-state accuracy but also significantly improves transient performance during interception.