Three-dimensional Finite-time Guidance Law And Integrated Guidance And Control For Intercepting Maneuvering Target

With the complexity of the war environment and the diversity of space weapons,missiles are required not only to attack stationary targets,but also to intercept maneuvering targets.Especially with the successful test of hypersonic aircraft and other flying weapons with high speed and high maneuverability,it is very important to design guidance laws that can intercept maneuvering targets with high precision and robustness.In addition,with the development of science and technology,miss distance is no longer the only criterion to judge the success of interception.In order to achieve a certain degree of damage,the missile is usually required to intercept the target at the desired impact angle.Therefore,this dissertation takes the missile intercepting maneuvering targets as the background,and considers the design of three-dimensional impact angle constraints terminal guidance laws with high precision and strong robustness.On this basis,the integrated guidance and control law is further considered.The main contents of this dissertation are as follows:Firstly,three-dimensional strong coupled nonlinear guidance dynamics are established for the missile intercepting maneuvering targets.Based on the fast nonsingular terminal sliding mode control theory,the three-dimensional finite time guidance law with impact angle constraints is studied,and the stability proof is also given by using Lyapunuov theory.Because the external disturbances of the guidance system includes maneuvering information,velocity information and angle information of the target,the precise upper bound value of them is usually very difficult to obtain.To solve this problem,a three-dimensional adaptive fast nonsingular terminal sliding mode guidance law with impact angle constraint is also proposed.In addition,the sign function makes sliding mode guidance laws discontinuous and leads to severe chattering phenomenon,which is a major factor hindering the application of sliding mold guidance laws to practical engineering.To solve this problem,improved reaching laws are studied.Based on the exponential reaching law,an improved reaching law is designed.According to the modified reaching law,a three-dimensional fast nonsingular terminal sliding mode guidance law with impact angle constraints is designed.On this basis,a improved finite time reaching law is further studied,and then,the guidance law which can guarantee the system asymptotically stable and finite-time stable is also designed.Because the sign function is still used,the designed guidance law can only weaken the chattering phenomenon to a certain extent rather than eliminate it.To solve this problem,a continuous reaching law is studied by combining the exponential reaching law and the double power reaching law,and a continuous guidance law is given according to the reaching law.The correctness of the designed guidance law is proved by strict Lyapunov stability theory,and the validity and superiority of the guidance law are verified by simulation analysis.Secondly,to design guidance laws for missile's actuators with physical constraints,three-dimensional guidance dynamics considering input constraints are established.On the basis of the designed dynamics and the integral sliding mode surface,a three-dimensional finite time guidance law is designed,which ensures the finite time convergence of systems under the bounded control input.Moreover,simulation results show that the designed guidance law can limit the missile acceleration value.At the same time,in order to solve the external disturbance problem,the finite time observer is used to compensate the external disturbance.Compared with two-dimensional guidance laws,three-dimensional guidance laws are more suitable for practical engineering applications.Further,the advantages of the three-dimensional guidance law in comparison with the two-dimensional guidance law are analyzed theoretically.In addition,a modified composite adaptive reaching law is designed to compensate the estimation error of the disturbance observer,and a new three-dimensional adaptive guidance law considering input constraints is designed.Finally,based on the above research on terminal guidance for missile intercepting maneuvering target,the three-dimensional integrated guidance and control problem is studied.Based on the backstepping method,a three-dimensional adaptive integrated guidance and control law is designed.The strict theoretical proof is given,and the effectiveness of the designed controller is verified by simulations.Considering that the actuator of the missile is restricted by physical conditions in actual application.Furthermore,a three-dimensional input constrained integrated guidance and control model is established,and an anti-saturation controller with impact angle constraints is designed.A smooth function is used to approximate the saturation function to handle differentiable the saturation function.Finally,a simulation experiment is given to demonstrate the effectiveness of the designed controller.