Research On Terminal Guidance With Attack Angle Constraint And Attitude Control Of Rolling Missile With Lateral Jets And Aerodynamic Surfaces

At present,due to the threat of all kinds of hypersonic weapons,high requirements are put forward for the maneuverability and interception accuracy of interceptors.When intercepting a target at high altitude,due to the low atmospheric density,the dynamic response capability of the traditional interceptor control system which only relies on the pneumatic rudder control may be greatly reduced.In order to solve this problem,PAC-3interceptor adopts the combined control mode of attitude control engine and pneumatic rudder in the terminal guidance stage.When the efficiency of the pneumatic rudder is reduced,the dynamic response capability of the traditional interceptor control system will be greatly reduced,The missile uses the impulse thrust of the attitude control engine to provide the control torque to make up for the lack of the control ability of the pneumatic rudder,and depending on its own height spin,it can make full use of the attitude control engine in different positions to change the attitude of the missile and improve the maneuverability.In addition,in the process of intercepting the target,in order to achieve better damage effect,the missile not only has the requirement of hit accuracy,but also needs to hit the target with a certain attack angle.In order to solve the design problems of guidance system and compound control system,and to deal with the various disturbances in the process of missile flight,this paper will take PAC-3 spinning missile as the research object,and design the terminal guidance law and the direct force-aerodynamic compound controller considering the attack angle constraint respectively based on the sliding mode control theory.First of all,the research status of rotary interceptor,guidance law under certain attack angle constraints and direct force-aerodynamic compound control method at home and abroad is investigated,and the main research content of this topic is introduced.Then,the mathematical model of the spinning missile is established,and the main shape and parameters of PAC-3 interceptor are investigated.In order to facilitate the follow-up research,several coordinate systems are defined and the conversion relationship between them is given.The main forces and moments of the spinning missile in the terminal guidance stage are analyzed,and the motion equation of the missile is established.Then,the attack angle constraint is analyzed and transformed into the line of sight angle constraint problem,and the assumption of guidance law design is established.Considering that the sliding mode control method has the advantages of fast convergence,strong anti-interference ability and easy design,based on the missile target relative motion model,the guidance law in the pitch plane is designed based on the exponential reaching law and terminal sliding mode control theory,and the guidance law in the threedimensional space is designed by using the state space method.The fast convergence ability of the guidance law is verified by simulation.Finally,the compound control model of PAC-3 spinning missile is established.The controllers of roll channel and pitch yaw channel are designed separately.The dual loop control strategy is selected to control the angular velocity and angle in pitch yaw channel.The interference of control loop is analyzed.The attitude control engine model is established.The ignition strategy based on command vector synthesis is selected.Considering the discrete characteristics of the direct force,the sliding mode control method is selected to design the control law.The direct force is regarded as the switching function of the sliding mode control law.In order to compensate the unknown disturbance and the error of the unmodeled term of the system,the extended state observer is used to estimate the disturbance and the rate of change of the command angular velocity,Based on this,a direct force / aerodynamic compound controller with certain anti-interference ability is designed,and the simulation is carried out under different forms of angle command input and different interference conditions.