Research On Sliding Mode Control Theory Based Guidance Algorithm

Tactical missiles destroying targets accurately is the common measure in modern battlefield,while multiple missiles salvo attack is a trend in future battlefield.Under this background,this paper gives a research on guidance laws and guidance algorithms for tactical missiles,investigates second order sliding mode control theory and super-twisting algorithm to strengths robustness and forces missile control system converge into sliding surface in finite time.Stabilities,feasibilities and practicalities of proposed guidance laws are illustrated via strict Lyapunov functions and mathematical simulations.First,choose interceptors as research object,establish physical engagement models,mathematical engagement models under tow-dimension environment and three-dimension environment,respectively.A disturbance observer and a second order sliding mode observer are investigated to estimate target maneuvering value.Based on second order sliding mode theory and super-twisting algorithm,a guidance law is proposed,which can force line-of-sight angular rate converge into zero in finite time,to make sure the missile intercepts target precisely.Based on this,a guidance law with impact angle constraint is proposed.Generalize finite time convergent guidance law into three-dimension environment.The character finite time convergence of these guidance laws are discussed via novel strict Lyapunov functions,and mathematical simulation results show that missile can intercept target preciously under this background.Then,give a research on multiple missiles salvo attack,design impact time and angle constraints guidance laws,set up physical model and mathematical model of cooperative guidance phase,investigate the expressions of desire impact angle and time-to-go.Based on super-twisting algorithm,a second order sliding mode guidance law is presented,which can force the system states converge into sliding surface in finite time.Generalize this algorithm into three-dimension environment,set up a physical model to divide missile's total velocity along three directions,and divide three-dimension motion into two planes.Simulation results show that propose guidance laws can satisfy the requirements of flight time constraint,attack angle constraint and salvo attack.Last,give a research on multiple missiles cooperative guidance,investigate the concepts of coordination variable,coordination function,double-deck cooperative guidance construction and so on.Establish physical model and mathematical model for cooperative guidance phase.Based on super-twisting algorithm,a switching guidance law is proposed,which restrains impact time firstly,and restrains impact angle when missile is near to target.Choose every missile's time-to-go as coordination variable,substitute it into coordination function to plan the optimal time-to-go.Hence the multiple missiles can worked synchronously.The effectiveness of proposed flight time constraint guidance law,attack angle constraint guidance law,switching guidance law and double-deck cooperative guidance construction is illustrated via mathematical simulations.