Research On Three Dimensional Guidance Law Design With Limited Perception

Since the Second World War, many great military powers competitively have developed a variety of missiles for different purposes. The great missile family have already been the symbolic weapons with modern high technologies evidently. The guidance ability of great precision is the most significant performance index to the missile. The relative motion model of missiles-targets is a tremendously complicated time-variant and nonlinear system. Based on a series of mathematics, physics and control theories, the design of guidance laws is full of challenges.For decades, many researchers are immersed themselves in the projects of missile guidance law design. Earliest the classic guidance laws such as the proportional guidance law and its improved ones have a broad range of application. With the development of targets’ velocity and maneuvering ability, the modern guidance laws based on modern control theories are emerging rapidly, for instance, optimal guidance law, differential game guidance law, sliding mode guidance law, adaptive guidance law, and etc. Later intelligence control theories come forth and develop, which stimulate researchers to explore the new intelligence guidance laws such as fuzzy guidance laws and neural network ones.Under the support of the national science foundation "Nonlinear control and applications to the guidance of maneuvering targets", a research of maneuvering targets guidance law design based on limited perception in the homing guidance mode is put in practice in this paper.The most important tasks of this paper are comprised of the following:1. Model establishment of missiles-targets relative motionRegarding the missile and target as particle, combining inertial frame attached to the center of missile mass and dynamic three dimensional sphere coordinate, we establish the three dimensional nonlinear model of sphere coordinate, which is able to nicely describe the relationship of relative motion between missile and target.2. Evaluation of the information necessitated by guidance law with the situation of limited perceptionThere are two situations of missile seekers’limited perception. One is the necessary information combined noises, which can be filtered by the hypothesis of Gaussian white noise. The other one is the information limitation, designing observers to evaluate.3. Adaptive sliding mode three dimensional guidance law design based on observersWith the three dimensional sphere coordinate nonlinear model of the missile-target relative motion, an adaptive sliding mode guidance law is designed based on sliding mode variable structure control theory. Stability analysis is carried out by Lyapunov stability theory. And meanwhile the necessary information is evaluated by high-gain observers.4. Three dimensional guidance law design based on radial basis function neural network gain adjustmentUtilizing the three dimensional sphere coordinate nonlinear model of the missile-target relative motion, and adopting input-to-state stability as well as radial basis function neural network theory, a three dimensional guidance law is designed. In addition, the gain adjustment can be operated on line by RBF. It can effectively avoid the undershoot augment by gain fixation and large-scale maneuvering of target.5. Computer simulations and analysesBased on the Matlab software simulation platform, after basic parameters assumed, computer simulations of guidance laws are carried out, and the theoretical analyses are made to verify the feasibility, validity and robustness.