Guidance Law And Integrated Guidance And Control For Intercepting Maneuvering Target

With the increasing complexity of the operational environment and the continuous improvement of the target mobility,higher requirements are put forward for the missile guidance and control system.In the process of terminal guidance,the target usually makes a large maneuvering escape and the maneuvering information is difficult to obtain accurately.In addition,in order to improve the damage effect of the missile warhead,the missile is required to hit the target at a desired terminal impact angle.Aiming at the situation of intercepting maneuvering targets,this dissertation studies the design of guidance law considering the terminal impact angle constraint and the design of guidance law considering the terminal impact angle constraint and the autopilot dynamics simultaneously.On this basis,we further excavate the relationship between the guidance and the control subsystems,and study the design of the integrated guidance and control for intercepting maneuvering targets.The main contents are as follows:First,the missile-target relative motion model and the missile nonlinear dynamic model are established.By taking the transformation of the missile acceleration vector in the line of sight coordinate system and the ballistic coordinate system as a bridge and fully considering the relationship between the guidance and control subsystems,a three channel coupling integrated design model is established.Then,the design of the terminal impact angle constrained guidance law is studied.On the one hand,a novel fixed-time nonsingular terminal sliding mode surface is constructed and the adaptive technology is used to estimate the upper-bound of the unknown target acceleration.On this basis,a fixed-time convergent guidance law is presented.The Lyapunov stability theory is used to analyze the closed-loop system’s stability.The effectiveness of the presented guidance law is verified via the numerical simulation.On the other hand,a time-varying sliding surface is constructed,and the fractional power extended state observer is used to estimate and compensate the unknown target acceleration.On this basis,a three-dimensional guidance law is proposed.The Lyapunov stability theory is used to analyze the closed-loop system’s stability.The effectiveness of the presented guidance law is verified via the numerical simulation.In the sequel,the design of guidance laws with the terminal impact angle constraint and autopilot dynamics is studied.On the one hand.extended state observers are introduced to estimate the unknown target acceleration and the derivative of the missile acceleration.Then the guidance is developed on the basis of the time-varying sliding mode and backstepping.In the design process,the tracking differentiator is used to deal with the “differential explosion” problem.The stability of the closed-loop system is proved by using Lyapunov stability theory and the effectiveness of the designed guidance law is verified through the numerical simulation.On the other hand,by using the extended state observers to estimate the unknown target acceleration and the derivative of the missile acceleration,two cascaded dual-loop guidance laws are proposed.The former is based on nonsingular terminal sliding mode and the latter is based on time-varying sliding mode.The outer-loop controller is used to generate the virtual acceleration command to achieve the convergence of the system states,and the inner-loop controller is used to generate the guidance command to track the virtual acceleration command generated from the outerloop subsystem.The second-order command filter is used to generate the first-order and second-order derivatives of the virtual signal at the same time.The proposed guidance law for the fourth-order guidance system is accomplished in just two steps.The stability of the closed-loop system is proved by Lyapunov stability theory and the effectiveness of the proposed guidance laws are verified by the numerical simulation.After that,the design of three-channel coupling integrated guidance and control law with the terminal impact angle constraint is studied.The fractional power extended state observers are used to estimate and compensate the uncertainties of the system to enhance the robustness of the system.A time-varying sliding mode surface is constructed,and the IGC control law is designed based on the backstepping method.In each design step,the tracking differentiator is introduced to avoid the “differential explosion”.The Lyapunov stability theory is used to analyze the closed-loop system’s stability.The effectiveness of the presented guidance law is verified via the numerical simulation.Finally,the design of three-channel coupling integrated guidance and control law with the constraints of the terminal impact angle and states is studied.The fractional power extended state observers are used to estimate and compensate the uncertainties of the system to enhance the robustness of the system.An integrated guidance and control law is designed by combining the time-varying sliding mode method and the backstepping method.In the design process,an improved saturation function is used to limit the amplitude of the virtual control signal,and the characteristics of the barrier Lyapunov function are used to constrain the system state.The Lyapunov stability theory is used to analyze the closed-loop system’s stability.The effectiveness of the presented guidance law is verified via the numerical simulation.