Trajectory Optimization And Lateral-directional Stability Analysis Of Hypersonic Vehicles

In recent years, hypersonic vehicle became a hot research topic. It owned high flight speed andwide flight height. Due to the characteristics of the hypersonic vehicle, which adopted advancedpropulsion technology and had a fast time-varying, strong coupling and strong nonlinear behave,trajectory design and stability analysis of hypersonic vehicle became a great challenge.This paper introduced several direct methods in trajectory optimization by analyzing trajectoryoptimization research progress. Direct methods included direct shooting, direct collocation, Gausspseudospectral method, Legendre pseudospectral method and Radau pseudospectral method. Thispaper presented a hybrid method based on Gauss pseudospectral method and Legendrepseudospectral method. This paper did an ascent trajectory optimization using above methods, andmade a comparison and analysis of the advantages and disadvantages of these direct optimizationmethods. The result of trajectory optimization confirmed the hybrid method was high-precisionand had advantages that other pseudospectral methods owned. This paper gave suggestions inmethod selection and optimization strategy.Because hypersonic vehicle had a great high speed and a wide scope of flight height, itsaerodynamic characteristics changed significant during the flight. This paper established the lateraldirectional stability criterion, and did a stability analysis for the example hypersonic vehicle.The results of this paper can be a reference for hypersonic task design control system designand guidance law design...