Towards Closed-Loop Control of Unstart in Scramjets: Development of Tools for Optimal Design of Sensors and Actuators

This research program proposes to make significant advances toward a novel framework for optimal design of sensors and actuators for use in closed-loop control of dual-mode scramjet engines. The proposal specifically aims to implement control theoretic methods to aid the user in determining the optimal configuration of sensors/actuators for improved detection and control of unstart. During the Phase I effort, two main tasks are proposed: 1) analyze a wide range of fast-response pressure transducer locations in an effort to determine particular configurations of sensors that best predict transient behavior of the unstart-shock system behavior; and 2) quantify the time-scales and sensitivities associated with fast and distributed (multiple) actuator schemes on the unstart-system dynamics. Pulsed air jets will be the focus of Phase I but the methodology is meant to apply to any actuator type or combination of types. The major emphasis of this research effort will be placed on how to optimally cross-correlate the sensor signals with the goal of deriving an early/timely precursor signal of impending rapid changes to the shock-state. These insights when coupled with the fast and coordinated actuators will form the backbone of a robust closed-loop unstart-control system. BENEFIT: The proposed research effort will make significant progress toward achieving critically needed sensor and actuator performance characterization data to enable the robust design of active control systems for scramjet engines. Military and commercial applications include but not limited to space launch vehicles, time-critical weapon systems, strike/reconnaissance vehicles, and systems related to space access.