The Study Of Missile Guidance And Control System With Fixed-time Convergence

With the continuous improvement of modern battlefield requirements,as an important member of modern weapons,missile has been widely valued by all countries.On the one hand,the traditional separation design of guidance and control system has gradually developed to integrated guidance and control with better performance;on the other hand,the traditional one-to-one attack with a single missile has evolved to the simultaneous attack with multiple missiles.The guidance and control system of missile is developing towards intellectualization and high efficiency.In recent years,with the strong robustness and high precision advantages of fixed-time theory,it has become a research hotspot for the majority of scholars.This paper focuses on the application of fixed-time theory in integrated guidance and control design and the guidance law design of simultaneous attacks with multiple missiles.The main contents of the paper are as follows:First,the problem of partial integrated guidance and control(IGC)design with fixed-time convergence is considered.Two new fixed-time stability systems are proposed,and a novel nonsingular terminal sliding mode with fixed-time convergence is constructed by switching the exponential term of system state variables.Concurrently,a continuous piecewise function is used in the sliding mode surface design to solve the singular problem.In addition,a radial basis function(RBF)neural network is used to adaptively estimate and compensate for the uncertainties,which enables the proposed controller to be better with robustness.And the proposed scheme is applied to the partial IGC design with two-loop controller structure.Second,a novel fixed-time extended state observer based fixed-time integral terminal sliding mode controller for partial IGC design is studied.A class of arbitrary-order systems with fixed-time stability is proposed by utilizing a homogeneous approach,whose upper bound of convergence time is given.An arbitrary-order fixed-time integral terminal sliding mode control is designed based on the proposed system,which avoids the singular problem.Subsequently,a new fixed-time extended state observer(ESO)is constructed to further actively compensate for the disturbance caused by unknown target acceleration.Third,a fixed-time salvo attack guidance scheme with impact angle constraint on maneuvering target is proposed for multiple missiles by using the cooperative control strategy.A fixed-time ESO is introduced to accurately estimate the target accelerations.The proposed guidance scheme is divided into parts,that is,the guidance law on the normal direction of the line of sight(LOS)and that along the LOS direction,of which the former one ensures the LOS angle converges to the desired value in fixed-time,and the latter one ensures the relative range consensus error converges to origin in fixed time,so as to achieve the salvo attack.Finally,a three-dimensional(3-D)fixed-time convergence guidance scheme for intercepting a stationary target is designed for impact time and LOS angle control.Two improved fixed-time stable systems and an improved fixed-time ESO are presented.Furthermore,an improved fixed-time sliding mode controller is derived.The proposed guidance procedure is divided into two stages by introducing a virtual target and a virtual leader.In the first stage,the proposed fixed-time sliding mode guidance law is employed,which ensures that the missile intercept the virtual target with desired LOS angles at a specific time.Then,the missile keeps travelling with invariant flight-path angle to hit the real target by using the proportional navigation guidance law in the second stage,so as to achieve the impact time and LOS angle control.