空 空 导 弹 敏 捷 转 弯 固 定 时 间 收 敛 滑 模 控 制

Based on the fixed-time stability theory and disturbance rejection mechanism，a method for sliding mode control is proposed for the agile turn when an air-to-air missile intercepts a target in the rear hemisphere of the carrier. First，a mathematical model for air-to-air missile with blended lateral thrusters and aerodynamic control systems is es⁃ tablished considering the aerodynamic disturbance. Next，by introducing the segmented nonlinear function to a double-variable-power sliding mode，a fixed-time convergent nonsingular sliding mode controller is designed. Then，to weaken the chattering in sliding mode control，a fixed-time convergent double-variable-power Extended State Observer （ESO）is designed to realize precise estimation of matched aerodynamic disturbance，so as to compensate for the control law. Based on the Lyapunov stability theory，the fixed-time stability of the system is proved，and the expres⁃ sion for the convergence time is given. Finally，simulation and analysis of the missile agile turn is given to validate the effectiveness of the theoretical results. Compare with previous controllers，the controller proposed allows the missile to complete agile turns at different initial states in a small fixed time，converge more quickly，weaken the chattering effec⁃ tively and improve the control efficiency.