Research On Control Methods For Longitudinal Dynamics Of Hypetsonic Flight Vehicles

Hypersonic flight vehicles work in near space and can achieve rapid global attack with high speed. The development of hypersonic flight vehicles will have a decisive impact on the military, business, and even the entire technology. The vehicles have complex dynamics due to the tight couplings between structural and propulsion systems, and are extremely sensitive to the variations in flight conditions. Reliable and effective control technology is the key to ensure the flight safety of the vehicles.First, the parametric method is applied to the control design in the asymptotic problem for longitudinal dynamics of a generic hypersonic flight vehicle. The corresponding force and torque coefficient are inserted into the state equations and we obtain a first ord er system model with the states directly affected by the inputs. Considering the asymptotic problem, the error model of the first order system is established, converting the asymptotic problem into a stabilization problem. The control law is designed based on the parametric method and simulation results are presented to demonstrate the feasibility of the proposed design method.Second, based on dynamic surface control technique, traditional neural control and global neural control are designed in this paper for longitudinal dynamics of a generic hypersonic flight vehicle. The longitudinal dynamics is formulated into the velocity subsystem and the altitude subsystem by model transformation. For the altitude system with flight path angle, pitch angle and pitching rate, it is with strict feedback form and dynamic surface control is studied to eliminate ―the explosion of complexity‖ in back-stepping design. Based on the dynamic surface control, this paper gives the controller directly from the dynamic model and a ll the unknown dynamics ih is approximated by neural network. Stability analysis is given by selecting a Lyapunov function and the uniform ultimate boundedness stability of the closed-loop system is guaranteed. Simulation results are presented to demonstrate the feasibility of the proposed design method.