Novel Hierarchical Modular Control Methodology for Closed-Loop-Flow Control Applications

Abstract

An ovel hierarchical modular control methodology using closed-loop flow control for active virtual shaping of aerodynamic surfaces is developed. Through wind tunnel experimentation and numerical simulation, we show that collocated sensor‐actuator pairs and closed-loop feedback control can effectively modulate the local flow phenomenon and, furthermore, by coordinating the local flow phenomenon, macroscopic force and moment effects can be induced on the aerodynamic surface. The results of flow experiments at Mach 0.08 on a two-dimensional airfoil are used to construct a dynamic model of the effect of discrete suction actuators, and a closed-loop adaptive control system is designed to modulate the local flow phenomenon based on this model. A feedforward control system is then constructed to coordinate the behavior of multiple intelligent control modules, each composed of a collocated sensor‐actuator pair and a closed-loop control system. In conclusion, we use a full six-degree-of-freedom numerical simulation to investigate the application of the aggregate system to tracking desired rolling and pitching moment trajectories via actuator-induced aeroshaping of the aerodynamic surfaces of an aircraft. NPRECEDENTED levels of air vehicle performance will be required to meet mission-specific objectives in the combat arenas of the near future. To accomplish this, future air vehicles will need to be highly maneuverable, stealthy, and reliable. These air vehicles will be required to maintain their ability to control and maneuver with limited or even no use of traditional (hinged) control surfaces. Some air vehicles with unconventional designs (nonaerodynamic surfaces) may be needed for carrying certain types of sensors and armament. It is possible that advanced control techniques will be required to enable new air vehicle designs that retain and improve their aerodynamic efficiency, even without the full use of traditional control surfaces. Closed-loop flow control offers great potential in revolutionizing the flying capabilities of air vehicles by means of virtual aerodynamic shaping. Virtual shaping of an aerodynamic surface refers to the modification of the flowfield around the surface by means of mass/momentum/energy transfer, which results in the fluid flowing around the surface as if the surface geometry is altered. This modified flowfield leads to a desired change in aerodynamic forces and moments. Consequently, virtual aerodynamic shaping has the potential to enable air vehicle designs that are dictated by mission-specific requirements as well as aerodynamic performance requirements.