Missile Control And Cooperative Guidance Based On Sliding Mode Control Theory

With the development of computer network and information technology,the missile,one of high-tech weapons,develops towards accuracy and clustering.Missile guidance and control systems need to satisfy more requirements in modern battlefield environment.However,the missile control system model is characterized as nonlinear and tight coupling,which results in the difficulty to obtain the atmospheric parameters and dynamic characteristics in complex flight environment.In addition,the missile system is affected by both parameter uncertainties and external disturbances.Therefore,designing robust and adaptive controller is an effective solution to resolve above problems.Accurate missile control system can correctly and rapidly track the guidance command,achieving precise attack.In view of complex battlefield environment,the missiles have not only high guidance precision but also the capability of coordination with other missiles by information interaction,to complete complex and difficult task.Researches show that cooperative guidance under impact time and angle constraints can ensure the accurately attacking from different directions simultaneously,which especially improves the damage effect against the target.Considering above problems,this paper works on missile precise control and cooperative guidance.The sliding mode control.with characteristics of strong robustness and model reduction,is appropriate for missile control and guidance.This paper investigates the missile control and cooperative guidance based on the sliding mode method,combining with other modern control methods including the consensus algorithm,adaptive control,the back-stepping method,disturbance observers and stability theory.The compound control strategies would be designed to guarantee the control objectives,achieving good performance.The main content of this paper is organized as follows.Firstly,the nonlinear missile attitude control system with parameter uncertainties and external disturbances is researched.As the adaptive back-stepping method has advantage to deal with mismatched uncertainty,a robust adaptive back-stepping attitude controller is designed.In the proposed controller,the robust strategy is used to eliminate the external disturbances.The controller has adaptiveness and strong robustness,achieving good tracking performance.Then,an adaptive back-stepping controller based on sliding mode disturbance observer(SMDO)is proposed.The SMDO is effectively to estimate the external disturbances,which is introduced to the feedforward compensation of the control law,reducing the control input.And the adaptive back-stepping controller based on the SMDO has precise,fast and good tracking performance.Secondly,cooperative guidance laws intercepting fixed target and maneuvering target are researched.Fixed target and maneuvering target are equivalent to the multi-missile interception system without or with external disturbances.In order to transform the problem of cooperative guidance law design into the coordination control of coordination variables,the time-to-go is introduced as an extra state variable into system dynamics.In the case of attacking fixed target,the cooperative guidance laws of intercept time and line-of-sight angle channels are designed based on the consensus algorithm.In the case of intercepting maneuvering target.considering the target acceleration has unknown bound,taking advantage of sliding mode method deals with matching uncertainty,the adaptive sliding mode controller is proposed based on the consensus algorithm.The proposed controller can guarantee the system states reaching the sliding mode surfaces in the finite time.Then the consensus protocols can guarantee the system states into the sliding mode surfaces to obtain control objectives.Compared with conventional adaptive sliding mode method,the switching magnitude of the proposed controller is adapted to the external disturbances.In addition,the chattering phenomenon of sliding mode method is reduced.Thirdly,the cooperative guidance law is researched based on the high-order sliding mode control.The second-order sliding mode controllers of intercept time and line-of-sight angle channels are designed,which can guarantee the system states reaching the integral sliding mode surfaces in the finite time.Then the consensus protocols can guarantee the system states into the sliding mode surfaces to obtain control objectives.As the actual control input of the second-order sliding mode is continuous,the chattering phenomenon of sliding mode is eliminated.Furthermore,another cooperative guidance law of line-of-sight angle channel is designed based on the sliding mode observer.The sliding mode observer is used to estimate external disturbances,reducing the control input as well as improving the angle tracking performance.Finally,considering cooperative guidance on leader-follower communication topology,the cooperative guidance law based on the optimal trajectory leader is designed.The leader guidance law with angle constraint is designed based on the optimal control theory.And the leader provides the reference information for the followers.Missile-target relative motion equations of both the leader and followers are normalized to facilitate the controller design.The sliding mode cooperative guidance law based on consensus algorithm is designed to ensure that the normalized state variables of followers can keep tracking to the leader's.Then the multi-missiles simultaneously attack the target with desired impact angles respectively.