Design Of A Flight Controller For An Unmanned Research Vehicle With Control Surface Failures Using Quantitative Feedback Theory

This thesis describes the application of the multiple-input multiple- output (MIMO) Quantitative Feedback Theory (QFT) design technique to the design of a digital flight control system for the Lambda Unmanned Research Vehicle (URV). The QFT technique allows the synthesis of a control system which is robust in the presence of structured plant uncertainties. Uncertainties considered in this design are the aircraft's plant variation within the flight envelope and the effects of damage to aircraft control surfaces. Mathematical models of control surface failure effects on aircraft dynamics are derived and used to modify an existing small perturbation model of the Lambda. The QFT technique is applied to design a control system utilizing aircraft pitch rate, roll rate and sideslip angle as feedback variables. The inherent cross-coupling rejection qualities of QFT and an aileron-rudder interconnect are utilized to design a control system which results in a coordinated flight. An outer-loop autopilot is then designed around the QFT controller to further assist turn coordination. Sensor noise effects on aircraft states are also analyzed. Quantitative feedback theory, Flight control system, Aircraft damage.

Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.

Masters Theses in the Pure and Applied Sciences was first conceived, published, and disseminated by the Center for Information and Numerical Data Analysis and Synthesis (CINDAS)* at Purdue University in 1957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dis semination phases of the activity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the thought that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this joint undertaking we had concluded that it was in the interest of all concerned if the printing and distribution of the volumes were handled by an international publishing house to assure improved service and broader dissemination. Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Corporation of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 38 (thesis year 1993) a total of 13,787 thesis titles from 22 Canadian and 164 United States universities. We are sure that this broader base for these titles reported will greatly enhance the value of this impor tant annual reference work. While Volume 38 reports theses submitted in 1993, on occasion, certain uni versities do report theses submitted in previous years but not reported at the time.

This thesis describes application of digital multiple-input multiple- output (MIMO) Quantitative Feedback Theory (QFT) technique to the design of a three axis rate controller for the Lambda Unmanned Research Vehicle. The resulting robust controller performs well throughout the flight envelope without gain scheduling. It results from research done at the Air Force Institute of Technology. The Lambda URV was designed by the Control Systems Development Branch of the Wright Laboratory at Wright-Patterson AFB, OH for flight testing aircraft control hardware and software. The flight control system is built using a small perturbation linear model developed from flight test data. The actuators, also modelled from aircraft test data, are second order in roll and pitch and first order in yaw. Nineteen separate plants are used to represent the flight envelope of the aircraft resulting from variations in speed, altitude, center of gravity location, and weight. The sample rate is 50 Hertz. The pitch channel is decoupled from the lateral-directional resulting in a single-input single-output (SISO) system for the pitch channel and a two-by-two MIMO system for the lateral-directional channel. The design employs the Nichols Chart and is accomplished in the w'-domain.

Cited in Sheehy, Chen, and Hurt . Volume 38 (thesis year 1993) reports a total of 13,787 thesis titles from 22 Canadian and 164 US universities. As in previous volumes, thesis titles are arranged by discipline and by university within each discipline. Any accredited university or college with a grad

Aerospace vehicles are by their very nature a crucial environment for safety-critical systems. By virtue of an effective safety control system, the aerospace vehicle can maintain high performance despite the risk of component malfunction and multiple disturbances, thereby enhancing aircraft safety and the probability of success for a mission. Autonomous Safety Control of Flight Vehicles presents a systematic methodology for improving the safety of aerospace vehicles in the face of the following occurrences: a loss of control effectiveness of actuators and control surface impairments; the disturbance of observer-based control against multiple disturbances; actuator faults and model uncertainties in hypersonic gliding vehicles; and faults arising from actuator faults and sensor faults. Several fundamental issues related to safety are explicitly analyzed according to aerospace engineering system characteristics; while focusing on these safety issues, the safety control design problems of aircraft are studied and elaborated on in detail using systematic design methods. The research results illustrate the superiority of the safety control approaches put forward. The expected reader group for this book includes undergraduate and graduate students but also industry practitioners and researchers. About the Authors: Xiang Yu is a Professor with the School of Automation Science and Electrical Engineering, Beihang University, Beijing, China. His research interests include safety control of aerospace engineering systems, guidance, navigation, and control of unmanned aerial vehicles. Lei Guo, appointed as "Chang Jiang Scholar Chair Professor", is a Professor with the School of Automation Science and Electrical Engineering, Beihang University, Beijing, China. His research interests include anti-disturbance control and filtering, stochastic control, and fault detection with their applications to aerospace systems. Youmin Zhang is a Professor in the Department of Mechanical, Industrial and Aerospace Engineering, Concordia University, Montreal, Québec, Canada. His research interests include fault diagnosis and fault-tolerant control, and cooperative guidance, navigation, and control (GNC) of unmanned aerial/space/ground/surface vehicles. Jin Jiang is a Professor in the Department of Electrical & Computer Engineering, Western University, London, Ontario, Canada. His research interests include fault-tolerant control of safety-critical systems, advanced control of power plants containing non-traditional energy resources, and instrumentation and control for nuclear power plants.