Real-Time Control for Mitigation of Air Vehicle Gust Response
Abstract
The objective of the proposed system is to provide the unique capability to study the unsteady aerodynamics and closed-loop control,of air vehicles in unsteady flows, wakes, and gust encounters. Interest in the aerodynamics of gust encounters has grown quickly ove,r the past 10 years, largely motivated by a desire to expand the operational envelope of unmanned air vehicles. The proposed system,is designed to generate strong discrete transverse gusts, where the gust flow is a large enough disturbance to cause flow separation, and stall. This type of gust encounter is therefore typified by the formation and shedding of strong vortices that result in large,force and moment transients on the wing and persist into the wake. Coupled with real-time closed-loop control capabilities and time-,resolved flow sensing and diagnostics, the proposed system will enable experiments to explore real-time control approaches for gust,response mitigation. Future work will build on existing knowledge of the fundamental characteristics of flow separation in a large-d,isturbance gust to explore methods of mitigating transient gust responses and the application of real-time clo,ust response mitigation. The proposed system is a major upgrade to the existing gust-enabled water tank at UMD to allow for more com,plex unsteady and three-dimensional gust flows, and real-time closed-loop model control. The proposed system includes upgrades to th,e gust generator, real-time control hardware, and flow sensors and instrumentation for in-the-loop control. This system also include,s the instrumentation necessary to quantify three-dimensional and non-uniform gust encounters on fixed and rotary wings for studies,of flow physics and aerodynamic model development for model-based control.For large flow disturbances, a water-filled towing tank is, an ideal facility because it is relatively straightforward to generate discrete transient flow disturbances via a stationary gust g,enerator that produces a flow through which a test model can be maneuvered. The time scales over which a water flow evolves are slow,er than in air, making it possible to perform relatively aggressive flow actuation or wing maneuvers, and the slower time scales and, higher density of water make it possible to acquire measurements at very high temporal and spatial resolutions with a high signal-,to-noise ratio. Test models of many different configurations including both fixed and rotary wings can be towed through the gust fie,ld, now allowing for variable gust velocity profiles and a pulsed unsteady gust. Flowfield, surface pressure, and direct force/momen,t measurements can be used to quantify a wings response to a gust encounter, and time-resolved particle tracking velocimetry can be, used to quantify the three-dimensional flow structure, wake development, and recovery. Coupled with real-time control hardware, ins,trumented test models can be driven in maneuvers to regularize gust response with measurements in the control loop. Experiments can,be performed to study vehicle response to and recovery from a gust encounter, optimal sensor and actuator placement, and control alg,orithm design for both isolated vehicles and swarms. The gust-enabled towing tank, time-resolved flow diagnostics, real-time control,, instrumented test models, and minimal rapid prototyping and machining capabilities comprise a unique state-of-the-art system to ge,nerate a well-defined large-amplitude gust field and quantify the effect of gusts on the flow over air vehicles, the forces/moments,turbance.Publicly Releasable; Submitted to: ONR Code 351, PM: David Gonzalez
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 05, 2022
- Source ID
- N000142212265
Entities
People
- Anya Jones
Organizations
- Office of Naval Research
- United States Navy
- University of Maryland