Design And Simulation Of Guidance And Control System For Guided Bombs

Guided bombs are airborne guided munitions fired by the carrier to accurately strike the ground targets.In the modern local wars after World War II,guided bombs have achieved brilliant combat effectiveness in actual combat due to their characteristics of low cost,long range and high precision,and thus have drawn wide attention from various countries military.This dissertation takes a guided missile as a research object,and preliminarily studies guidance law design,projectile dynamic characteristics analysis,guidance control loop design and digital simulation.The main research works are as follows:First of all,based on the typical working process of guided bombs,common coordinate systems used to describe the movement of guided bombs are established.The relationships among the coordinate systems are explained and the transformation matrix between the coordinate systems are given.Then a kinetic and kinematic model of guided bombs is established.Secondly,according to the operational characteristics of the guided bomb,the composite guidance system with medium guidance + terminal guidance is adopted.In the medium guidance section of the guided bomb,the range of the guided bomb is effectively improved by tracking the trajectory of the pre-designed program.In the terminal guidance section,based on the vector algorithm,the guidance equation of three-dimensional proportional guidance method is deduced to ensure that the guided bomb can accurately hit the target.On this basis,the nonlinear time-varying model of projectile is simplified into a linear time-invariant model by using small perturbation hypothesis and coefficient freezing method,and then the dynamic characteristics of the typical working condition of the guided bomb are analyzed.Thirdly,based on the guidance system of the guided bomb and the dynamic characteristics analysis of the projectile,the guidance control system scheme of the guided bomb using the calibration network / proportional guidance + autopilot is determined.Because of the maneuvering way of the guided bomb and the axial symmetry,the aerodynamic coupling is small.In this paper,the kinetic model of the guided bomb is decoupled into three channels: pitch,yaw and roll.Then the autopilots are designed for three control channels based on the undetermined coefficient method.In order to improve the response and robustness of the system,this paper also optimizes the parameters of autopilots based on Particle Swarm Optimization.In addition,in order to realize the accurate trajectory tracking of the guided bomb in the medium guidance section,the classical control theory is used to design a calibration network for the guidance loop.Finally,the guided bomb is regarded as a six-degree-of-freedom controllable rigid body for full digital simulation.And based on the Monte Carlo method,the digital simulation of the guided bomb is carried out under the disturbance conditions.Then the circular error is calculated.In addition,the influence of different disturbance parameters on the accuracy of guided bomb is analyzed.