US Air Force and DARPA developing a complete hypersonic vehicle by 2023 and China looking at morphing hypersonic vehicles

The Air Force and DARPA are researching and will build a next generation hypersonic vehicle by 2023. It will use some of the X-51 tech that is capable of operating “at the kind of temperatures you have when you are going at hypersonic speeds.” They are developing a guidance system that can still function at Mach 5.

The Pentagon also hopes that costs could be lowered over a traditional turbine engine because of fewer parts in the hypersonic system.

Here is an open access article on the topic of hypersonic control and guidance by Chinese researchers. International Journal of Aerospace Engineering – Collaborative Deformation Design Using Control Integrated Analysis Methods for Hypersonic Waverider

Hypersonic waveriders have a large flight envelope, leading to the difficulty in keeping overall flight stability for a fixed geometry. Accordingly, hypersonic waveriders can be considered to design as a morphing vehicle such that the flight range is expanded for waveriding stability. To this end, this paper investigates the collaborative deformation design using control integrated analysis methods for the hypersonic waverider. Firstly, a parametric model is applied to combine the shape deformation with the geometrical properties. Secondly, the morphing process with regard to the change in a single geometric parameter and the static and dynamic characteristics affected by this deformation are analyzed. Afterwards, the collaborative relations are discussed for the changes in the lower forebody angle and elevon area. Furthermore, a flight control law is designed to guarantee flight stability while implementing the collaborative deformation, and the morphing results are evaluated based on the control-oriented idea. Finally, a simulation example is used to verify the effectiveness of the proposed methods for the hypersonic waverider.

A cancelled Blackswift hypersonic project design

Interest in hypersonic vehicles has origins in two main applications. The first is to provide a reliable and cheap way to space. The second is to realize a fast response to potential threats around the globe.

Typically, hypersonic vehicles are characterized by long, slender geometries with highly coupled engines and airframes, and such configurations make that the vehicle model is nonlinear, multivariable, and strong coupling and includes complicated dynamics and uncertain parameters. More importantly, hypersonic vehicles are sensitive to flight conditions and states such as the dynamic pressure and angle of attack; as a result, deviating from the design point will lead to the deterioration of waveriding performances. To this end, hypersonic vehicles can be considered to apply the morphing technologies for the purpose of enhancing the overall performance.

Recently, the trade-off studies are paid more attention for the control-oriented design of hypersonic vehicles. This is due to the presence of the complex interactions in a hypersonic vehicle, involving aerodynamics, propulsion, control, and so on.

There is University of Alabama abstract about a hypersonic control paper.

The increasing complexity of hypersonic systems requires integrated analysis ofguidance, navigation, and control (GNC) systems to better understand subsystem interactions early in the design cycle to improve system performance and assess program cost. In this presentation, an integrated, GNC-focused analysis of drag modulation as a means of hypersonic trajectory control is discussed, followed by a comparison of lift and drag-modulation trajectory control systems. Drag modulation is shown to be an effective means of trajectory control that is potentially simpler than current state-of-the-art lifting systems. Mars Science Laboratory-class downrange errors are shown to be achievable with a dragmodulation entry, descent, and landing architecture. Analytical approximate solutions to the equations of motion are used to assess and compare lift and drag-modulation trajectory control schemes, resulting in design guidelines that may be used to inform system selection early in the design cycle. A research campaign is proposed to improve integrated GNC system design and performance through application of multidisciplinary design and optimization techniques to algorithm and mission design, modeling and simulation, flight software, and GNC hardware; these integrated analyses have application across a broad range of aerospace systems.

A 2015 paper by Chinese authors on an overview of hypersonic flight dynamics and control

Commonly studied hypersonic flight dynamics models such as the wing-coned model, truth model, curve fitted model, control oriented model and re-entry motion are reviewed. Various linearization and back-stepping approaches are reviewed. Recent research on hypersonic flight control are reviewed and compared.

SOURCES –, University of Alabama, International Journal of Aerospace Engineering