Research On Aerodynamic And Correction Of Two-dimensional Trajectory Correction Projectile Based On Precision Guidance Kit

In order to provide a reference and theoretical basis for the design of the aerodynamic shape and the optimization of the ballistic correction of the two-dimensional trajectory correction projectile,the US military 155 mm M107 grenade projectile based on precision guidance kits is used as the research object.The required external ballistic aerodynamic parameters are obtained through fluid dynamics theory and simulation.The basic image of aerodynamic parameters is obtained through data processing,and the aerodynamic parameter function is fitted by numerical methods.Based on the basic theory of aerodynamics and angular motion theory,the projectile flight stability analysis and criterion comparison are carried out.Rewrite and simplify the projectile’s six-degree-of-freedom rigid body motion equation,compare and analyze the longitudinal and lateral capabilities of the correction projectile,and obtain the optimal correction mechanism selection and the influence of the independent variable factors of the rudder on the correction ability.In order to determine the research model of the two-dimensional trajectory correction projectile,the basic composition,working principle and roll angle control principle of two-dimensional trajectory correction projectile are summarized and summarized,M107 grenade body and the precision guidance kit are combined to form a two-dimensional trajectory correction projectile model for simulation.According to the model pictures and other documents,the main parameters of the two-dimensional trajectory correction projectile after the combination of the two,including the correction mechanism rudder blade rudder deflection angle 4°,rudder height 35 mm,rudder thickness 3 mm and rudder length 52 mm and the situation which simulation study needs to change are synthesized.In order to achieve the basic fitting of the aerodynamic parameters of the two-dimensional trajectory correction projectile,the basic theory of aerodynamics and Fluent fluid simulation software are used to simulate the full trajectory of the correction projectile at different angles of attack and the resistance coefficients of each sound velocity stage under different rudder blades.The data of six aerodynamic parameters such as,lift coefficient,etc.provide a theoretical basis and data basis for the study of the aerodynamic characteristics of the two-dimensional trajectory correction projectile and the fitting of functional relationships.Through the aerodynamic parameters obtained from simulation,the aerodynamic parameter images of the two-dimensional trajectory correction projectile from 0.2 Ma to 2.4Ma and their relationship with the angle of attack,rudder deflection angle,rudder height,rudder thickness and rudder length in each sound speed stage are drawn.Firstly describe its relationship qualitatively.Then,the least square method is used to fit the function relationship between each aerodynamic coefficient and the Mach number,the angle of attack and the independent variable factors of the rudder blade.Finally,the error analysis is carried out,all are within the acceptable range,and the fitting function is credible,which also verifies the feasibility of this method of quickly obtaining the aerodynamic parameters of the two-dimensional trajectory correction projectile under different conditions.In order to study the feasibility of applying the existing flight stability theory and empirical formula to the correction projectile,the angle motion theory is used to derive the stability criterion suitable for the two-dimensional trajectory correction projectile to further demonstrate its flight stability and two The flight stability of the projectile is different,and the pros and cons of the two criteria are compared.It is concluded that the modified projectile has gyro,following and dynamic stability in the whole trajectory,but it is inferior to the ordinary rotating projectile with the same bullet shape,and the derived gyro and dynamic stability criterion is more accurate and more suitable for correcting the projectile,while following stability The criterion is more accurate,but the margin of the original judgment moment is larger,and it is more suitable for amending the bomb.In order to study the influence of the self-variation factors of the correction component on the longitudinal and lateral correction capabilities of the two-dimensional trajectory correction projectile,the fitting function of the aerodynamic parameters was substituted and Matlab was used to simplify and rewrite the six-degree-of-freedom rigid body motion equation of the revised projectile,the fourth to fifth order Runge-Kutta method was used to solve the ballistic equation,and when the full trajectory is corrected,the range of the modified projectile is significantly reduced than that of the projectile which is not corrected at all,and the lateral deviation is significantly increased.It has obvious two-dimensional correction capabilities.When the trajectory vertex is corrected,the two-dimensional correction capability is significantly reduced.The 8° rudder deflection angle,the 41 mm rudder height,the 4 mm rudder thickness and the 54 mm rudder length are the optimal correction mechanism selection when considering the longitudinal and lateral correction capabilities and flight stability.And the 8° rudder deflection angle,the 41 mm rudder height,the 4 mm rudder thickness and the54 mm rudder length are considered as the optimal correction mechanism selection when corrected at the trajectory vertex.It is concluded that for the projectile longitudinal correction ability,the rudder thickness has the greatest influence,the rudder deflection angle is the second,and the rudder height and the rudder length have the least influence and are relatively close;for the projectile lateral correction ability,the rudder deflection angle has the greatest influence,and the rudder length and The rudder height is second,the rudder length is greater than the rudder height,and the rudder thickness is the smallest.At the same time,it is alos conclued that the roll angle error nearly has no effect on the longitudinal correction capability,but has a certain effect on reducing the lateral deflection of the corrected projectile,that is,it will reduce the lateral correction capability,and as the roll angle error increases,the lateral correction capability decreases more and the trend of change is gradually increasing.