Trajectory Optimization And Flight Control Of The Guided Rocket

With the advantages of low cost,high power and easy operation,the rocket has been widely used in modern warfare.Due to the advancement of modern military technology,the development of the rocket is proceeding towards the direction of guidance and long-range.In order to obtain the long-range strike capability of the rocket,gliding extended range technology can be used to achieve the purpose of increasing the range by reasonably optimizing the rocket trajectory while meeting the process constraints and terminal constraints.The research on the optimization o f rocket trajectory is a significentt research content in the field of rocket weapons,which has high research value and broad application prospect s.The long-range guided rocket with two-stage rocket engine is taken as the research object ive,and the method of gliding flight is used to expand the range.This paper focuses on the research of trajectory optimization of the rocket,and takes the maximum range as the optimization objective to obtain the trajectory.In addition,the trajectory tracking control problem of the glide phase is studied,and the controller is designed to track the optimized flight trajectory.The main research contents are as follows:Treat the guided rocket as a particle and establish a three-dimensional trajectory mathematical model to conduct preliminary research and discussion on trajectory planning.Several sets of parabolic flight trajectory simulation experiments with different initial launch angles are designed to stud y the influence of launch angle on the range.The whole trajectory planning scheme of the rocket controlled by the subsection angle of attack is given,and the appropriate value of the angle of attack in the glide phase is determined to realize gliding flight and increase the trajectory range.The simulation is conducted to determine the ignition time of second-stage engine,and the results show that the ignition of the second-stage engine at a certain interval after the shutdown of first-stage engine is more conducive to the increase of the trajectory range than the ignition at the starting point of the glide phase.Aiming at the the effects of different trajectory deflection angles and thrust deviations of the rocket on trajectory,comparative experiments are conducted to discuss their impact on the flight trajectory.The trajectory optimization scheme of multi-constraints glide phase based on hp-adaptive Radau pseudospectral method is designed to optimize the glide phase,and the simulation results show that the method could increase the range.And on this basis,the contrast experiments are conducted to get the influences o f different initial glide height and terminal speed constraint on the trajectory.The results show that the lower initial glide height corresponds to a longer trajectory range,and the range objective is in conflict with the final speed objective,so the maximum values of two objectives cannot be obtained at the same time.Aiming at the contradiction between the range objective and the final speed objective,a multi-objective optimization scheme of glide section based on the MOEA/D algorithm is designed for the research.The simulation results verify the feasibility of the algorithm,but the algorithm requires high computational performance when it actually works.Aiming at the problem of whole trajectory optimization of the rocket,the trajectory is divided into two phases with the trajectory vertex as the middle point,the maximum speed and maximum range are taken as the optimization objectives respectively.Then the pseudospectral method is used to optimize the whole process of the two phases,and the simulation results show that the trajectory range has been greatly improved.For the obtained optimal trajectory of the glide phase,a tracking controller design method using lift coefficient and lateral force coefficient as auxiliary control variables is proposed,and the trajectory tracking control is realized by using t he sliding mode control theory.Aiming at the situation where the system is disturbed and the upper bound of the interference is known,a general sliding mode tracking controller is designed using integral sliding mode surface and exponential reaching law.Aiming at the situation where the system is disturbed and the upper bound of the interference is unknown,an adaptive sliding mode tracking controller is proposed to track the obtained trajectory.The simulation experiment is conducted on the basis of the designed controller,and the results show that the designed controller could realize the trajectory tracking task well.