Control of an Air-Breathing Hypersonic Vehicle with Scramjet Engine Constraints

Hypersonic flight has gained significant attention in recent years due to its promising applications in the civil and military fields. Such flight vehicles are typically powered by supersonic combustion ramjet (scramjet) engines. Control of these scramjet-powered, air-breathing hypersonic vehicles (AHVs) is a complex task due to the highly nonlinear nature of their dynamics and the inherent coupling between their aerodynamics and propulsion. Moreover, the scramjet is very sensitive to the flow conditions at its inlet, namely the angle of attack (AOA), and can stop operating once it reaches Mach-number dependent limits.

This thesis presents a nonlinear controller for the AHV that ensures it operates within limits dictated by the propulsion system characteristics. The controller was constructed using a well-known model for the longitudinal dynamics of the AHV actuated by an elevator, canard, and the scramjet engine. Several model simplifications were introduced to facilitate the design of a simpler controller than the previously reported ones in the literature. The controller performance objectives are described by a control Lyapunov function (CLF) whereas the engine-related constraints are specified by a control barrier function (CBF). Unifying these performance and constraint objectives, the controller design task is stated as a quadratic program (QP). This QP is solved analytically to yield a controller that minimizes a pre-determined cost function and, thus, also exhibits a certain degree of optimality. The resulting controller shows good tracking performance while ensuring no constraints are violated. This is demonstrated in simulations in the face of model uncertainty and disturbances.

The work is towards M.Sc. degree under the supervision of Associate Professor, Moshe Idan, Technion, Aerospace Engineering Faculty