Dynamics Analysis And Control System Design For Rolling Guided Projectile

With the needs of modern warfare,the artillery weapon system is undergoing a revolutionary transformation and upgrading from surface-covered firepower to long-range precision strikes.The guidance of artillery shells is the key to long-range precision strikes.Different from missile weapons,the guidance control system for guided projectiles has its own particularity.However,the rolling of the airframe brings about the problem of flight stability and cross-coupling between pitch and yaw channels while reducing the cost.It has a serious impact on the precision of the guidance and control of the projectile,and must be considered in the design of the guidance and control system.This paper takes the long-range rolling guided projectile as the research object,and takes the dynamic analysis of the airframe and the design of the control system as the main research contents.Firstly,based on the commonly used coordinate systems,angles and the mutual conversion relationship between these coordinate systems,the force analysis of the flight process of the rolling guided projectile is performed,and the complete equations of flight process of the low-speed rolling guided projectile are established.It provides a mathematical model for the dynamics analysis and control system design of the guided projectile.Secondly,based on the reasonable simplification and assumption of small perturbation,a linearized equation system of the disturbed body motion is established.Based on this,the shell body transfer function is deduced,and the dynamic stability condition and instability mechanism of the rolling body are analyzed.An open-loop control system was designed for the guided projectile.When the open-loop control does not meet the requirements of the guidance system,the method of dynamic adjustment of the projectile was analyzed.Thirdly,in order to improve the performance of the guidance system,a lateral acceleration autopilot was designed to stabilize the attitude of the projectile.Several main factors that cause the cross-coupling between the control system pitch and yaw channels are discussed.Classical two loop lateral acceleration autopilot is designed.The simulation results show that the dynamic performance of the control system is good after the introduction of the autopilot,but the coupling between the pitch and yaw channels causes serious control errors.In order to improve the control precision,the decoupling of the control coupling caused by the delay of the servo’s dynamics is decoupled and the decoupled autopilot is designed.The simulation verifies its good decoupling performance.Finally,for the problem that it is difficult to compensate the coupling of the body’s movement and the poor robustness of the classic two-loop autopilot,the nonlinear control theory is used to design a robust autopilot controller that combines feedback linearization decoupling with sliding mode variable structure control.The autopilot controller was simulated and analyzed.The results showed that the designed autopilot can quickly and accurately track guidance command and has strong robustness.