Adaptive sliding mode attitude control of 2-degrees-of-freedom helicopter system with actuator saturation and disturbances

The modelling uncertainties, external disturbance and actuator saturation issues will degrade the performance and even the safety of flight. To improve control performance, this study proposes an adaptive U-model based double sliding control (UDSMC) algorithm combined with a radial basis function neural network (RBFNN) for a nonlinear two-degrees-of-freedom (2-DOF) helicopter system. Firstly, the adaptive RBFNN is designed to approximate the system dynamics with unknown uncertainties. Furthermore, two adaptive laws are designed to deal with unknown external disturbances and actuator saturation errors. The global stability of the proposed helicopter control system is rigorously guaranteed by the Lyapunov stability analysis, realizing precise attitude tracking control. Finally, the comparative experiments with conventional SMC and adaptive SMC algorithms conducted on the Quanser Aero2 platform demonstrate the effectiveness and feasibility of the proposed 2-DOF helicopter control algorithm

Thrust control design for unmanned marine vehicles

Thesis (Master)--Izmir Institute of Technology, Mechanical Engineering, Izmir, 2012Includes bibliographical references (leaves: 65-70)Text in English; Abstract: Turkish and Englishxv, 74 leavesIn conventional electrically driven propulsion systems with fixed pitch propellers, thruster controllers are usually aimed at controlling propeller shaft speed only. Especially in unmanned marine vehicles which operate in dynamic flow conditions, these type thruster controllers provide unsatisfactory thrust responses. The reason for this is that the thrust force is simultaneously affected by dynamic effects like, variable ambient flow velocity and angle, thruster-thruster interaction and ventilation. It is aimed to achieve acceptable thrust tracking accuracy in all kind of dynamic flow conditions in this thesis work. A novel feed-back based thruster controller which includes the effect of incoming axial flow velocity, is designed for this purpose. In controller design, first, thruster propeller's open water characteristics in four-quadrant flow states are measured. Data collected from open water tests are then non-dimensionalized and embedded in the controller's thrust model code. Relation between ideal shaft speed and desired thrust is derived by using the four-quadrant propeller model. The proposed method is evaluated in the experimental test-setup designed for this study to simulate open water conditions. Results indicate that thrust tracking performance of novel controller is acceptable in all four-quadrant flow tests

Aeronautical Engineering: A special bibliography with indexes, supplement 64, December 1975

This bibliography lists 288 reports, articles, and other documents introduced into the NASA scientific and technical information system in November 1975

Aeronautical engineering: A continuing bibliography with indexes (supplement 195)

This bibliography lists 389 reports, articles and other documents introduced into the NASA scientific and technical information system in December 1985

Aeronautical Engineering: A continuing bibliography with indexes, supplement 153, October 1982

This bibliography lists 535 reports, articles and other documents introduced into the NASA Scientific and Technical Information System in September 1982

A robust, reliable and deployable framework for In-vehicle security

Cyber attacks on financial and government institutions, critical infrastructure, voting systems, businesses, modern vehicles, etc., are on the rise. Fully connected autonomous vehicles are more vulnerable than ever to hacking and data theft. This is due to the fact that the protocols used for in-vehicle communication i.e. controller area network (CAN), FlexRay, local interconnect network (LIN), etc., lack basic security features such as message authentication, which makes it vulnerable to a wide range of attacks including spoofing attacks. This research presents methods to protect the vehicle against spoofing attacks. The proposed methods exploit uniqueness in the electronic control unit electronic control unit (ECU) and the physical channel between transmitting and destination nodes for linking the received packet to the source. Impurities in the digital device, physical channel, imperfections in design, material, and length of the channel contribute to the uniqueness of artifacts. I propose novel techniques for electronic control unit (ECU) identification in this research to address security vulnerabilities of the in-vehicle communication. The reliable ECU identification has the potential to prevent spoofing attacks launched over the CAN due to the inconsideration of the message authentication. In this regard, my techniques models the ECU-specific random distortion caused by the imperfections in digital-to-analog converter digital to analog converter (DAC), and semiconductor impurities in the transmitting ECU for fingerprinting. I also model the channel-specific random distortion, impurities in the physical channel, imperfections in design, material, and length of the channel are contributing factors behind physically unclonable artifacts. The lumped element model is used to characterize channel-specific distortions. This research exploits the distortion of the device (ECU) and distortion due to the channel to identify the transmitter and hence authenticate the transmitter.Ph.D.College of Engineering & Computer ScienceUniversity of Michigan-Dearbornhttps://deepblue.lib.umich.edu/bitstream/2027.42/154568/1/Azeem Hafeez Final Disseration.pdfDescription of Azeem Hafeez Final Disseration.pdf : Dissertatio

Aeronautical Engineering: A special bibliography with indexes, supplement 89, November 1977

This bibliography lists 538 reports, articles, and other documents introduced into the NASA scientific and technical information system in October 1977

Aeronautical engineering: A continuing bibliography with indexes, supplement 140

This bibliography lists 386 reports, articles, and other documents introduced into the NASA scientific and technical information system in September 1981

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