Adaptive Control Of Spin Guided Projectile With Input Constraints

Nowadays,guided missile technology is developed an important branch of weapons science.In the flight process,the spin-guided projectile spin around the vertical axis caused by yaw and yaw channel aerodynamic coupling,showing a strong nonlinear coupling characteristics.In addition,due to the limited output of the actuator,the aerodynamic parameters show the phenomenon of uncertainty and wide range of changes.The system is easy to enter the nonlinear saturation.It is no doubt that increases the difficulty of control system design.Based on the above,this paper studies the problem of restricted control and establishes linear and nonlinear dynamic model.The PID controller,anti-saturation PID algorithm,sliding mode algorithm,inversion algorithm,anti-windup compensation algorithm and restricted auxiliary algorithm are used to design the controller.Achieve stable control of angular velocity and overload.Firstly,based on Newtonian mechanics,the paper analyzes the forces and moments suffered by them and establishes a six-degree-of-freedom trajectory model.A linear dynamic model is established by uses of "small disturbance" and linearization hypothesis combined with "coefficient freezing method",and then the transfer function of missile body is derived by Laplace transform.In view of the transfer function model,the three-loop and saturated three-loop autopilot are designed.The design of damping ring and stabilizing ring are designed by root locus method and verified by the combination of frequency domain analysis and time domain analysis.The overload loop is designed by PID algorithm and the outer loop is designed by anti-windup compensator.The PID three-loop autopilot and saturated PID three-loop autopilot are designed for the transfer function.The control algorithm is simulated.Secondly,in order to study the nonlinear control properties of spin-guided projectiles,a simplified and coupling dynamics model was derived using simplified assumptions.For the sake of study and solve the coupling nonlinearity between pitch and yaw channel,the sliding mode algorithm is used to design a dual-channel autopilot.A novel adaptive sliding mode surface is designed combining with integral sliding surface,differential sliding surface and tenninal sliding surface so that the system can reach and maintain the sliding surface from the beginning,and the hyperbolic tangent switching function is used instead of symbol switching to eliminate the chattering of the system.Furthermore,in order to solve the nonlinear problem caused by saturation control,this paper designs an anti-windup compensation controller based on the idea of compensation.Through the comparison of the limited before and after the simulation,make the tracking error approach to zero.Finally,aiming at the problem of non-linearity caused by input limitation,a simplified and coupling dynamic model of spin-guided projectile is standardized and transformed into a"standard block-controlled model".The control structure of overload and angular velocity is designed using back stepping method.Constrained inversion sliding mode control law.By introducing a sliding mode control algorithm with zero-order sliding mode and hyperbolic tangent switching function,the chattering of the system is reduced,and then the error variable caused by the saturation of the actuator is introduced to design the Auxiliary System.By adding the restricted auxiliary system before and after the simulation comparison,the results show that the restricted auxiliary system facilitates the rapidity,reduces the steady-state error,restrain the saturation and can realize the stable control of overload.