Blended Homing Guidance Law Using Fuzzy Logic By

The application of fuzzy logic for the development of guidance laws for homing missiles is presented. Fuzzy logic approximation of the well known proportional navigation guidance law is discussed, followed by the development of a blended guidance law using fuzzy logic. The objective of the latter guidance law is to combine desirable features of three homing guidance laws to enhance the interception of targets performing uncertain maneuvers. Fuzzy logic guidance law development employs triangular, trapezoidal and sigmoidal membership functions. Mamdani-style inference is employed in the fuzzy inference system. Simulation results using point-mass missile model and a spiraling, high-speed ballistic target model are given. Introduction Naval vessels are subject to threats from enemy tactical ballistic missiles and sea-skimming missiles [1]. These threats may be fast and maneuverable, and may employ unknown evasive strategies and stealthy airframes. Engagements against these threats can occur over a wide range of flight conditions. The missile dynamic model may be highly uncertain at these flight conditions. Uncertainties can arise in aerodynamic data and can include previously unknown and unquantified coupling effects. Ship defense missile guidance and control systems must be capable of delivering agile performance while handling nonlinearities and uncertainties in the vehicle model, atmosphere, and ambient winds. The focus of the present paper is on the development of fuzzy logic guidance laws capable of handling large uncertainties in the missile model. Two different guidance laws are discussed. The * President, Associate Fellow AIAA + Research Scientist