Abstract:

An analytical three-dimensional nonlinear H∞ guidance law is designed for coping with measurement noise and disturbance and unknown target maneuvering in the process of a missile intercepting an attacking target. By building a three-dimensional relative motion equation between the missile and the target in the modified polar coordinate and a relative motion equation between the missile and the target involving many types of measurement noise and disturbance, a simplified system equation of the missile intercepting the target is deduced. Then the corresponding HJI partial differential inequality is constructed by using nonlinear control theory. And then a solution method of HJI partial differential inequality is offered. Thus a set of analytical solutions and a positive definite storage function are obtained, and then the analytical three-dimensional nonlinear H∞ guidance law is designed successfully. By analyzing the relationship of the design parameters of nonlinear H∞ guidance law and several key interception factors of guidance, the analysis qualitatively points out that how to adjust design parameters can deal with a variety of adverse factors and improve guidance performance further more. Finally, simulation results verify the effectiveness of the proposed guidance law and the effectiveness of the qualitative analysis.

Key words: Guidance Law, Nonlinear H∞ control, Simplified relative motion equation of missile intercepting target, Target maneuvering, HJI partial differential equation