The Attitude H_? Control Of A Spin-stabilized Projectile With A Gyro-like Structure

The centroid velocity of flighting projectiles deflect and trajectories are bent due to gravity.In the meantime,the main spindle of the projectile deflects under the action of aerodynamic moments and deviated from the initial spinning direction.The deflection of the main spindle relative to centroid velocity is non-axisymmetric,which cause drift of the trajectory.Now there are many methods to realize attitude and ballistic control,but most of them shrink the firing range of projectiles.In order to overcome the difficulty,a gyroscopic structure is added in the interior of the projectile and work under H_?state feedback controller,according to the principle of mass tuning technology.The main studies and results are as follows.Firstly,the mathematical model of the spinning projectile with a gyroscopic structure is established.Through the method of‘complex plane',the similarity of mathematical model between the spinning projectile and the tuned mass technology is explained.The ballistic differential equations are derived according to Lagrange's Equation.The simplified model I and II are obtained with reasonable assumptions and the initial conditions.Secondly,the motion characteristics of simplified model II are discussed and analyzed preliminarily.Calculate the eigenvalues and eigenvectors of the simplified model II and analyze the natural frequencies and modal modes of the system.The Poincare section is constructed to study the law of system motion.Derive the dimensionless equations.The Lyapunov exponents are calculated for quantitative analysis.All these three methods analysis results show that the motion pattern of the system has certain complexity varying with the system parameters.Finally,the attitude control law of projectile with a gyroscopic structure is designed and the relevant numerical simulation calculation is approached.Standard H_?control method is used to design the controller of the simplified model I and II,respectively.Simulation results demonstrate the effectiveness of the proposed method.The research work presented in this paper can provide a new idea for attitude control of the spinning stabilized projectile.