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The Dynamic Systems and Control Branch can trace its history back several decades during which a common research theme has been aircraft guidance and control. Several examples of specific work during that time follow. In the early 1970's branch members were responsible for developing digital control laws for the F-8 Fly-by-Wire airplane.
During this time period, it became clear that there was an urgent need for a software package of efficient and reliable algorithms to provide solutions to time invariant continuous or discrete linear quadratic gaussian (LQG) problems. In response to this need, a software package called ORACLS (Optimal Regulator Algorithms for the Control of Linear Systems) was developed to incorporate the best numerical methods that the rapidly developing state of the art in LQG theory was providing for isolated cases. ORACLS systematized these algorithms so that they could be applied efficaciously in an entire control system design. The software was made generally available through COSMIC In order to provide adequate models for model based control laws and to provide uncertainty bounds on theoretical or wind tunnel derived aerodynamic models, an extensive effort was undertaken in the field of system identification applied to aircraft flight data in the 1980's. System identification algorithms were developed and software written to extract aerodynamic model structure and associated parameters (stability and control derivatives) in both linear and nonlinear flight regions. These software included stepwise regression, maximum likelihood, and Kalman filtering techniques and were validated on a wide variety of line and research aircraft including general aviation, high performance fighters, transports, unpowered drop-models, and the Shuttle Orbiter. Also during that decade, working with engineers from Rockwell International Corporation, branch members designed control laws for the Active Flexible Wing (AFW). This concept, pioneered and advanced by Rockwell, exploited rather than avoided wing flexibility to provide weight savings and improved aerodynamics for advanced fighter configurations. The test bed for the AFW Program, an aeroelastically-scaled wind tunnel model of an advanced fighter configuration was extensively tested in Langley's Transonic Dynamics Tunnel. In the 1990’s work began on anticipating the problems that would be encountered by a National Aerospace Plane (NASP) type vehicle as it flew through an uncertain atmosphere. To investigate the effects that atmospheric uncertainties and inhomogeneities might have on such vehicles, branch members developed the NASP Integrated Atmospheric Model (NIAM). NIAM integrated features from the Global Reference Atmospheric Model (GRAM-90), a random turbulence model developed by McDonnell Douglas (PERT), and deterministic wind and gust models based on the NASP Natural Environment Requirements Document. The areas of expertise developed by people in the organization include classical and modern control theory; control law design for aircraft from conception through flight test and evaluation; batch, real time, and piloted simulation, flight test design and analysis of resulting data ; system identification and parameter estimation; aircraft mathematical modeling; and atmosphere modeling. These areas of expertise have been exercised with support of NASA research facilities including computers, wind tunnels, and aircraft. A number of memoranda of agreement (MOA) have been executed with industry for the exchange of data and expertise to the mutual benefit of the branch and the industry. Through these MOA's the branch expanded its available data sources to current and developing aircraft. It has also brought current problems in industry closer to the organization. |
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(Computer Software Management and Information Center) and at one point was the eleventh most often accessed program out of more that 2000 programs in the COSMIC inventory.