Modeling and active disturbance rejection control for sequential airdrop operations

With the assumption t at the motion acceleration of the cargo is unknown, the dynamic model that accords with the engineering practice of sequential cargo airdrop operations is derived by using the separation body method, which can describe the impact of the sequential moving cargos on the flight safety and airdrop-mission capacity. On this basis, a novel flight control method is designed based on the active disturbance rejection control (ADRC) theory. the system is decoupled and linearized through the nonlinear state error feedback; the total unknown disturbances, including unmolded dynamics and uncertainty, are estimated and compensated real-timely by the extended state observer. Moreover, with the consideration of the time-delay system, the ADRC is improved to enhance the accuracy and rapidity of the control system. Simulations are carried out under the condition that one transport aircraft performs sequential airdrop operations. The results verify that the desirable performance and robustness have been achieved and the proposed control method is quite competent for the sequential airdrop operations

Adaptive Fuzzy Sliding Mode Control of MEMS Gyroscope with Finite Time Convergence

This paper presents adaptive fuzzy finite time sliding mode control of microelectromechanical system gyroscope with uncertainty and external disturbance. Firstly, fuzzy system is employed to approximate the uncertainty nonlinear dynamics. Secondly, nonlinear sliding mode hypersurface and double exponential reaching law are selected to design the finite time convergent sliding mode controller. Thirdly, based on Lyapunov methods, adaptive laws are presented to adjust the fuzzy weights and the system can be guaranteed to be stable. Finally, the effectiveness of the proposed method is verified with simulation

Department of Defense Dictionary of Military and Associated Terms

The Joint Publication 1-02, Department of Defense Dictionary of Military and Associated Terms sets forth standard US military and associated terminology to encompass the joint activity of the Armed Forces of the United States. These military and associated terms, together with their definitions, constitute approved Department of Defense (DOD) terminology for general use by all DOD components

Controllable single-bladed autorotating vehicle

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2007.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 109-110).Accurate delivery of cargo from air to ground is currently performed using autonomously guided parafoil systems. These parafoils offer limited maneuverability and accuracy, and are often relatively complex systems with significant deployment uncertainty. The author has proposed, designed, and developed a novel precision airdrop system in the form of a samara. Consisting of a single wing, payload, and control system, the guided samara is mechanically simple, and when correctly configured, is globally stable during deployment and steady descent. The proposed control mechanisms grant the vehicle omni-directional glide slope control during autorotating descent. This is the first documented effort to develop an actively controlled vehicle of this form factor. The research presented in this thesis includes the conceptual design of the vehicle and several control schemes, development of a six degree-of-freedom computer simulation predicting the vehicle's flight performance, and the design, fabrication, and flight testing of a guided samara prototype. Over the course of the development, numerous free-flights were conducted with unguided samara models. Flight results and simulation results in various configurations yielded the discovery of several mechanisms critical to understanding samara flight. The free-flight simulation predicted descent and rotation rates within 10% of those observed during flight testing. Simulations of the guided samara predicted stability during control actuation as well as considerable control authority. Using a programmable microprocessor, hobby servo, and 2-axis electronic compass, a control system was developed. The guided samara prototype was flight tested at NASA Langley to attempt to demonstrate omni-directional glide slope control during descent.(cont.) Due to weather conditions and test circumstances, the demonstration was inconclusive. The simulation results and favorable performance of the developed control system indicate that guidance of the samara during autorotation is feasible, and only awaits favorable conditions for demonstration of this capability.by Andreas Kellas.S.M

Aeronautical Engineering: A continuing bibliography with indexes, supplement 110

This bibliography lists 504 reports, articles, and other documents introduced into the NASA scientific and technical information system in May 1979

Joint Publication 1-02

The Joint Publication 1-02, Department of Defense Dictionary of Military and Associated Terms sets forth standard US military and associated terminology to encompass the joint activity of the Armed Forces of the United States. These military and associated terms, together with their definitions, constitute approved Department of Defense (DOD) terminology for general use by all DOD components. This publication supplements standard English-language dictionaries and standardizes military and associated terminology to improve communication and mutual understanding within DOD, with other federal agencies, and among the United States and its allies

Aeronautical engineering: A continuing bibliography with indexes (supplement 321)

This bibliography lists 496 reports, articles, and other documents introduced into the NASA scientific and technical information system in Sep. 1995. Subject coverage includes: design, construction and testing of aircraft and aircraft engines; aircraft components, equipment, and systems; ground support systems; and theoretical and applied aspects of aerodynamics and general fluid dynamics

Aeronautical Engineering: A special bibliography with indexes, Supplement 35, September 1973

This special bibliography lists 614 reports, articles, and other documents introduced into the NASA scientific and technical information system in August 1973

Aeronautical Engineering: A continuing bibliography with indexes, supplement 155, December 1982

This bibliography lists 272 reports, articles and other documents introduced into the NASA scientific and technical information system in November 1982

Aeronautical Engineering: A cumulative index to the 1980 issue

This bibliography is a cumulative index to reports, articles, and other documents introduced into the NASA scientific and technical information system. Abstracts for the entries cited appeared in issues 119 through 130 of Aeronautical Engineering: A Continuing Bibliography (NASA SP-7037). Subject, personal author, corporate author, contract number, and report/accession number indexes are provided