Papers by Keyword: RLV

Abstract: in order to solve the poor adaptability problem with the traditional reentry guidance, A new evolved Acceleration Guidance Logic for Entry (EAGLE) is studied for the Reusable Launch Vehicle (RLV) here. According to the guidance, the reference drag acceleration profile is updated every period based on the predictive range-to-go. In the lateral profile, basing on the generated reference drag profile, two reversal times are got successively through numerical predictive method. The technique of feedback linearization is used to track the reference drag acceleration profile. The algorithms of updating the reference drag profile and searching reversal times are both the method of golden-section search, so the EAGLE method can be performed onboard. The simulation results based on different reentry conditions show that the approach has good robustness and real-time ability.

Abstract: In reentry flight phase of reusable launch vehicle (RLV), its aerodynamic characters alter sharply, going with serious uncertainties and nonlinearities. These factors make the reentry attitude control technique be one of key technique for RLV. In this paper, the sliding mode variable structure control technique is used for reentry attitude control. A specific switch function is defined; a specific exponential reaching law and continuous analogy of sign function are chosen to weaken the chattering brought by the variable structure control technique. RLV is equipped with aerosurfaces and reaction control system (RCS), the arithmetic based on dynamic pressure change is presented. Six-freedom nonlinear simulation with great gain and high frequency disturbance proves that the reentry attitude control technique performs very well, and its control accuracy and robustness are brilliant.

Abstract: Various technology programmes in Europe are concerned with preparing for future propulsion technologies to reduce the costs and increase the life time of components for liquid rocket engine components. One of the key roles to fulfil the future requirements and for realizing reusable and robust engine components is the use of modern and innovative materials. One of the key technologies which concern various engine manufacturers worldwide is the development of fibrereinforced ceramics – CMC's (Ceramic Matrix Composites). The advantages for the developers are obvious – the low specific weight, the high specific strength over a large temperature range, and their good damage tolerance compared to monolithic ceramics make this material class extremely interesting as a construction material. Different kind of composite materials are available and produced by EADS ST, the standard material SICARBON® (C/SiC made by Liquid Polymer Infiltration) and the new developed and qualified composite materials SICTEX® (C/SiC made by Liquid Silicon Infiltration) and CARBOTEX® (C/C made by Rapid Chemical Vapour Infiltration). The composites are based on textile techniques like weaving, braiding, stiching and sewing to produce multiaxial preforms, the SICTEX® material is densificated by the cost effective Liquid Silicon Infiltration (LSI). Over the past years, EADS Space Transportation (formerly DASA) has, together with various partners, worked intensively on developing components for airbreathing and liquid rocket engines. Since this, various prototype developments and hot firing-tests with nozzle extensions for upper and core stage engines and combustion chambers of satellite engines were conducted. MBDA France and EADS-ST have been working on the development of fuel-cooled composite structures like combustion chambers and nozzle extensions for future propulsion applications.