Research On Concept Design And Capability Analysis Of A New Variable Axis Reentry Vehicle

The velocity of hypersonic reentry vehicle is above 5Ma, and the reentry vehicle as a weapon has many advantages such as fast response and long-range precision strikes. Therefore, many countries have begun the study of hypersonic reentry vehicle and the study in this area has very important significance.There are two typical type in hypersonic reentry vehicles: one is the vehicles with high lift-drag ratio, such as "clipper" wing aircraft; the other one is on behalf of "clippers" wingless aircraft and HGB aircraft, which are aircraft with low lift-drag ratio. The first type has better maneuver abilities and heat flow value than the second type, but the second type has better characteristic of speed.In this paper in order to solve the high and low lift-drag ratio aircraft don’t have both high cross range, falling velocity, small re-entry flight time, a variant of the high and narrow, flat two direction axis aircraft is proposed. The cross section is oval, so that the flat direction characteristic area is bigger than the high narrow directional characteristic area. Under the same flow conditions, if the vehicle in the same Mach number and angle of attack flight, the lift-drag ratio of flat flight direction should be bigger than it of the narrow high under the direction.In this paper, in order to prove the reentry capability of proposed aircraft, firstly the related development of foreign reentry vehicle dynamic shape and reentry capability status is investigated. Then the three-dimensional model of aircraft is proposed and lead to CFD-FASTRAN to calculate the dynamic parameters under different condition.Through Gauss pseudospectral method for trajectory optimization design, sequence quadratic programming algorithm is chose to solve nonlinear programming problem and to generate standard trajectory. Each Gauss point are the points of route and between those points, the prediction-correction guidance is used to guide the vehicle until the vehicle is close enough to the target. Once it triggers, the vehicle has to regenerate the trajectory and use LQR controller tracking control. In the simulation, based on three kinds of trajectory optimization of the four variants of axis aircraft flight mode to carry on the simulation computation, each trajectory optimization under different flight patterns of reentry performance characterization parameters is got and can be used to analysis the capabilities of variable lift-drag ratio reentry vehicle.