Aeronautical Engineering: A special bibliography with indexes, supplement 51

This bibliography lists 206 reports, articles, and other documents introduced into the NASA Scientific and Technical Information System in November 1974

Efficient Parameterization of Nonlinear System Models:a Comment on Noel and Schoukens

Nöel, J. P., & Schoukens, J. [2018. Grey-box state-space identification of nonlinear mechanical vibrations. International Journal of Control, 91, 1–22] discuss a methodology for the discrete-time state-space identification of nonlinear systems and apply this to experimental data from the well known Silverbox nonlinear circuit, producing a model characterised by 13 parameters. This model explains the data very well but the parameter estimates are not well defined in the optimisation results, with the very large confidence bounds suggesting that the model is over-parameterised. This comment shows that this is indeed the case and that the data can be explained equally well by an alternative continuous-time, State-Dependent Parameter (SDP) transfer function model with only 6 parameters, the estimates of which are well defined with very tight confidence bounds. The comment also raises questions about how the model form for nonlinear systems such as the Silverbox should be identified and suggests that the Data-Based Mechanistic (DBM) approach to modelling has some advantages in this regard

Aeronautical Engineering: A continuing bibliography, supplement 116

This bibliography lists 550 reports, articles, and other documents introduced into the NASA scientific and technical information system in November 1979

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 139

This bibliography lists 381 reports, articles, and other documents introduced into the NASA scientific and technical information system in July 1981

Aeronautical engineering: A continuing bibliography, supplement 125

This bibliography lists 407 reports, articles, and other documents introduced into the NASA scientific and technical information system in July 1980

A cumulative index to Aeronautical Engineering: A special bibliography, January 1975

A cumulative index to the abstracts contained in NASA SP-7307 (41) through NASA SP-7037 (52) is presented. Subject, personal author, corporate source, contract, and report number indexes are included

Aeronautical Engineering: A continuing bibliography with indexes, supplement 137, July 1981

This bibliography lists 483 reports, articles, and other documents introduced into the NASA scientific and technical information system in June 1981

Control system development for autonomous soaring

Thermal and dynamic soaring are two techniques commonly used by birds to extract energy from the atmosphere. This enables them to reduce, energy used during flight and increases their endurance. The thermal soaring technique involves extraction of energy from thermal updrafts and in dynamic soaring energy is extracted from wind shear. These techniques are investigated in this thesis using point mass and non-linear 6DoF models of an unmanned powered sailplane. The key challenges of autonomous thermal soaring are the ability to identify remote thermal activity using on-board sensors and to position correctly in a thermal. In dynamic soaring, a real-time fuel saving trajectory generation technique along with a trajectory following control system is needed. A hand held IR camera was used to assess the feasibility to observe hot spots associated with thermals. The thermal positioning capability was demonstrated in a 6DoF model using a positioning algorithm. The inverse Dynamics Virtual Domain (IDVD) technique was used to generate real-time trajectories for dynamic soaring applications using a point mass model of a powered unmanned sailplane and the fuel saving trajectories were validated using a high fidelity 6DoF model and a classical controller. An important outcome of the research is the fact that energy saved during dynamic soaring flight was also realized due to a sinusoidal manoeuvre using reduced thrust. In this manoeuvre the kinetic energy is converted into potential energy by gaining altitude and by reducing airspeed. Then initial values of altitude and speed are gained by loosing the altitude. In this process a horizontal distance is travelled by using reduced thrust.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

A cumulative index to Aeronautical Engineering: A continuing bibliography

This bibliography is a cumulated index to the abstracts contained in NASA SP-7037(132) through NASA SP-7037(143) of Aeronautical Engineering: A continuing bibliography. NASA SP-7037 and its supplements have been compiled through the cooperative efforts of the American Institute of Aeronautics and Astronautics (AIAA) and the National Aeronautics and Space Administration (NASA). This cumulative index includes subject, personal author, corporate source, contract, and report number indexes