Project Title: Engineering and Feasibility Trade Studies for the NASA/VSGC MicroMaps Space Mission
Sponsor: Virginia Space Grant Consortium, NASA Langley Research Center
Description:Natural and/or human surface activities, such as biomass burning or industrial processing, release significant concentrations of gaseous by-products such as carbon monoxide (CO) into the atmosphere. These trace gases may have significant influence on the Earth's greenhouse effect and global climate trends. At this time, these large scale dynamic processes are not well understood. Further, scientific data such as CO spatial and temporal distributions for global atmospheric and climate prediction models is severely lacking. A critical need for expanded atmospheric CO databases exists so that accurate scientific predictions can be undertaken. MicroMaps is an existing NASA owned gas filter radiometer instrument designed for space-based nadir measurement of atmospheric CO vertical profiles. MicroMaps hardware has high potential for filling the critical scientific need, thus motivating concept studies for new and innovative scientific spaceflight missions that would leverage the MicroMaps heritage and investment, and contribute to new CO distribution data to be used in global-scale atmosphere and climate modeling and prediction. Project objectives include 1) assessing MicroMaps instrument space basing platform options, 2) surveying near term launch vehicle opportunities for MicroMaps space access, 3) supporting MicroMaps instrument check-out and refurbishment of electro-mechanical hardware and software activities, 4) investigating MicroMaps instrument on-orbit thermal control requirements and solutions to maintain scientific measurement integrity, and 5) analyzing imaging system options for the MicroMaps instrument system.
Project Title: Development of a High Accuracy Angular Measurement System for LaRC Hypersonic Wind Tunnel Facilities
Sponsor: NASA Langley Research Center
Description: Current angular measurement capability in LaRC high-speed wind tunnel facilities is lacking. These current systems are based on primitive mechanical measurement of the model sting pitch orientation. Pitch measurement accuracy is insufficient. Yaw and roll orientation measurement is not available and must be assumed. This project focuses on developing a modern and adaptable sensor package capable of measuring pitch, roll and yaw while also meeting the size and accuracy requirements stipulated by LaRC high-speed short duration wind tunnels. Utilization of a sensor package consisting of gyros, or a combination of gyros and accelerometers, is envisioned. Commercially available MEMS sensor technology is projected to have performance levels which can meet both size and accuracy requirements.
Project Title: LIDAR-Based Ride and Load Augmentation Flight Control
Sponsor: AeroTech Research
Description: New laser-based sensor technologies, such as Laser Imaging, Detection, And Ranging (LIDAR) systems, for in situ detection and measurement of unfavorable atmospheric states and motions are receiving increased attention for real-time flight applications. LIDAR-based sensors are projected to have significant in-flight potential for exposing and identifying adverse atmospheric conditions such as clear air turbulence and gust, horizontal and vertical shear layers, thunder cell drafts and microbursts, and even vehicle generated wake vortices and disturbances, which lie along the desired trajectory. LIDAR-based flight control opens new design freedoms for countering and lessening the effects of such disturbances. Project objectives are to investigate and/or assess control strategies for reducing the effects of flight through significant atmospheric disturbances on ride quality and load factor by utilizing LIDAR-based disturbance measurement data, while minimizing impacts on the baseline attitude control and trajectory guidance functions.
Project Title: New Control Concepts for Small Autonomous Hydrodynamic Vehicles
Sponsor: Vehicle Control Technologies
Description: New mission requirements for small autonomous submerged hydrodynamic vehicles, which serve as sensor platforms, are expected to strain or exceed the current capabilities of standard closed-loop vehicle systems, in terms of trajectory motion and attitude pointing accuracy. Low speed operational conditions result in low dynamic pressure requiring large angles of attack to maneuver. Large hydrodynamic attitudes will induce significant speed variations which must be controlled to meet mission design goals. Further, low speed conditions equate to reduced flow over the sternplane and low control authority. When speed variations become significant, and the tailplane is not able to deliver the necessary loads, alternate control architectures/strategies using additional control inputs, either already existing or altogether new, must be explored. Project objectives are two fold: 1) to investigate the feasibility of utilizing a conventionally designed two-channel tailplane/throttle control system architecture to extend the low speed envelope, and 2) to explore contemporary linear quadratic-based design methods to close the tailplane/throttle control loops, again to expand the low-end operational envelope.
Project Title: Control Design Strategies to Enhance Long-Term Aircraft Structural Integrity
Sponsor: NASA Langley Research Center
Description: Over the operational lifetime of both military and civil aircraft, structural components are exposed to hundreds of thousands of low-stress repetitive load cycles and less frequent but higher-stress transient loads originating from maneuvering flight and atmospheric gusts. Micro-material imperfections in the structure, such as cracks and debonded laminates, expand and grow in this environment, reducing the structural integrity and shortening the life of the airframe. Extreme costs associated with refurbishment of critical load-bearing structural components in a large fleet, or altogether reinventoring the fleet with newer models, indicate alternative solutions for life extension of the airframe structure are highly desirable. One area having significant potential for impacting crack growth/fatigue damage reduction and structural life extension is flight control. In principle, control loops can be utilized to influence the level of exposure to harmful loads during flight on structural components. Project objectives are to investigate and/or assess control strategies for reducing fatigue damage and enhancing long-term structural integrity, without degrading attitude control and trajectory guidance performance levels.
Project Title: Longitudinal Inner-Outer Loop Interface and Lateral-Directional Augmentation for HSR
Sponsor: NASA Langley Research Center
Description: The High-Speed Civil Transport (HSCT) is projected to be a heavily augmented vehicle with multiple feedback loops performing several functions. Flight Control System augmentation of the HSCT is being driven by various factors including poor low frequency handling characteristics, relaxed static stability and backside response reversal at low subsonic speeds, and significant interaction between rigid-body and aeroelastic degrees of freedom, as well as the need for tight control of angular orientation and flight path trajectory. Previous longitudinal flight control system design activities have addressed 1) scheduled linear, full-envelope outer loops utilizing a "gamma dot - V" architecture for quasi-static aeroelastic models and 2) linear, point-design inner loops utilizing "pitch rate command" architectures with small forward vanes for dynamic aeroelastic models. Lateral-Directional flight control system design activities have concentrated on a "P - beta dot" architecture for quasi-static aeroelastic models. Control of dynamic aeroelastic characteristics in the lateral-directional axes have not been addressed thus far. Project objectives are two fold: 1) to investigate feasible solutions for interfacing the independently designed inner and outer loop HSCT flight control system, and 2) to explore and/or assess candidate inner loop flight control system strategies for the lateral-directional HSCT axes.
Project Title: Multivariable Techniques for HSR Flight Control Systems
Sponsor: NASA Langley Research Center
Description: The High-Speed Civil Transport (HSCT) is projected to have a pitch divergence due to the relaxation of static stability at subsonic speeds. Further, significant interaction between rigid-body and aeroelastic degrees of freedom is expected. Functions of the inner most loops of the flight control system for HSCT will be to artificially supply the stability inherently lacking in the airframe, augment the key responses with crisp, well damped behavior, and to suppress, or lessen, aeroelastic motions in the rigid-body responses. Attainment of these multiple, conflicting closed-loop objectives inherently requires a dexterous flight control system architecture, which can sense key motions and apply critical forces/moments simultaneously at multiple points distributed throughout the vehicle. Project objectives are three fold: 1) to investigate contemporary multivariable design techniques for meeting the closed-loop objectives and to assess the "theoretically achievable" upper limits of stability/performance, 2) to explore the control benefits derived from an additional, small, forward aerodynamic control surface applicable to preliminary HSCT concepts, and 3) to establish requirements for levels of controllability of rigid and elastic responses that can be used to guide configuration design.
Project Title: Investigation of Inner Loop Flight Control Strategies for HSR
Sponsor: NASA Langley Research Center
Description: The High-Speed Civil Transport (HSCT) is projected to have a pitch divergence due to the relaxation of static stability at subsonic speeds. Further, significant interaction between rigid-body and aeroelastic degrees of freedom is expected. The objectives of an inner loop flight control system for HSCT will be to artificially supply the stability inherently lacking in the airframe, augment the key responses with crisp, well damped behavior, and to suppress, or lessen, aeroelastic motions in the rigid-body responses. To lower costs associated with flight control system development, validation, and modification, the attainment of multiple control objectives with minimal architecture is highly desirable. Here, the objective is to explore and/or assess candidate inner loop flight control system strategies for the HSCT.
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Last update: 02-01-01