Research On Dynamics Analysis And Control Of Guided Projectiles

Guided projectile is ahybrid of traditional projectile launching technology and modern missile precision navigation and control technology,and asymmetric rolling guided projectile is a kind of guided projectile with asymmetric mass distribution or aerodynamic shape caused by damage,machining or assembly error.It is a typical high dimensional nonlinear system with strong uncertainty,high coupling and fast time varying,and this makes the dynamics and control of asymmetric rolling guided projectile become an important scientific problemwith valuable basic theoretical research and engineering practice.Focusing on this important subject,in this paper,asymmetric rolling guided projectile dynamics modeling and simplification,dynamic characteristics analysis,study on bifurcation characteristic and control method design and so on several aspects are carried out in a deep research.First of all,according to the asymmetric rolling guided projectile motion with strong nonlinearity and strong coupling characteristics,considering nonlinear,induced aerodynamic with roll angle related and asymmetric aerodynamic forces and moments,a five dimensional angular motion and roll motion coupling dynamics model is established.The model can accurately describe the attitude motion.At the same time,the traditional six dimensions motion of dimensionality is reduced to the five-dimensional form,and therefore difficulty of analysis is reduced.Basing on this model,the system of forced vibration phenomenon caused by the asymmetric factor is studied,the influence of different parameters on the vibration amplitude and phaseis is discussed,and the roll lock-in triggering mechanism and the necessary condition are given.Next,based on the five-dimensional dynamics model,bifurcation analysis method is used to study the local nonlinear dynamic characteristics of asymmetric rolling guided projectile system.With the method of numerical calculation,multiple equilibrium points of the system state equations are calculated,the equilibrium point varing with the system parameters is studied and the change of distribution and the local stability of system is determined according to Lyapunov first method.By means of numerical simulation and analytical method,the influence of gravity on equilibrium point distribution and local stability of the system are studied.By means of the center manifold theorem,the complex system equations are reduced,and Hopf bifurcation theorem and the saddle-node bifurcation theorem are applied to determinethe types and properties of local bifurcations.According to the theory of singularity,the universal unfolding is calculated,and the system small disturbance effects on local bifurcation characteristics are studied.Then,based on the conclusions of equilibrium distribution and local bifurcation characteristics,global analysis such as global bifurcation pointsand global topological structuresare is carried out.Different attractors and domains of attraction of the system are calculated by cell reference point mapping method,and the effects of initial conditions on the system of global motion property are discussed.By plotting the Poincare mapping diagrams,calculating of numerical characteristics of power density spectrum and Lyapunov exponent,the existence of chaos motion of an asymmetric roll guided projectile is determined.The transition processes and boundary conditions of different nonlinear states such as the equilibrium point,periodic motion and chaos are presented.At last,for the nonlinear control of asymmetric rolling guided projectile,a five dimensional controlled motion model with uncertain disturbance is established.According to the principle of time-scale separation,two control loops are designed,and the controller is designed by using trajectory linearization control(TLC)method.A Lipschitz state observer is designed to solve the problems of TLC,such as the suppression of measurement noise and the estimation of uncertain parameters caused by asymmetric disturbance.To deal with the limitation of the TLC method in solving the problem of strong uncertainty,adaptive compensation control law is proposed based on the estimation of the system unknown disturbance by the use of Lipschitz state observer.The improved design of TLC method is realized,and the control efficiency and robustness of the improved mothed are verified by simulation experiments.