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Lau, Tak Kit. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 168-176). / Abstract also in Chinese. / Chapter 1 --- Introduction --- p.18 / Chapter 1.1 --- Motivation and Problem Statement --- p.18 / Chapter 1.2 --- Literature Review --- p.19 / Chapter 1.2.1 --- Avionics Design --- p.19 / Chapter 1.2.2 --- Controller Design --- p.21 / Chapter 1.2.3 --- Dynamics Analysis --- p.23 / Chapter 1.2.4 --- State Estimation for GNSS Outage --- p.24 / Chapter 1.3 --- Outline --- p.25 / Chapter 2 --- Actuation Dynamics --- p.26 / Chapter 2.1 --- Mcchanism Of The Rotor --- p.27 / Chapter 2.2 --- Mcchanism Of Swashplate And Rotor --- p.28 / Chapter 2.3 --- Numerical Analysis Of Cyclic Pitch Angle --- p.31 / Chapter 2.4 --- Helicopter Dynamics --- p.33 / Chapter 2.4.1 --- Aerodynamic Forces And Moments --- p.35 / Chapter 2.4.2 --- Aerodynamic Drag --- p.36 / Chapter 2.4.3 --- Incremental Lift --- p.36 / Chapter 2.4.4 --- Tail Rotor Thrust And Moment --- p.36 / Chapter 2.4.5 --- Deadweight And Moment --- p.37 / Chapter 2.5 --- The Conventional Inadequacy Of Adding A 90° Phase-Lag --- p.38 / Chapter 2.6 --- The Gyroscopic Effect In Helicopter Dynamics --- p.39 / Chapter 2.6.1 --- How Precession Works --- p.43 / Chapter 2.6.2 --- The Analytical Form --- p.45 / Chapter 2.6.3 --- Numerical Analysis Of The Gyroscopic Effect --- p.48 / Chapter 3 --- State Estimation For GNSS Outage --- p.52 / Chapter 3.1 --- GNSS Error And UAV Failure --- p.52 / Chapter 3.2 --- "Kalman Filter, And The Extended Kalman Filter" --- p.53 / Chapter 3.3 --- Unscented Kalman Filter --- p.54 / Chapter 3.4 --- Process And Measurement Model --- p.55 / Chapter 3.4.1 --- The IMU Driven Model And Sensor Error --- p.57 / Chapter 3.5 --- Modifications To The Model And UKF Algorithm --- p.62 / Chapter 3.5.1 --- Acceleration White Noise Bias (AWNB) --- p.62 / Chapter 3.5.2 --- Acceleration Scale (AS) --- p.64 / Chapter 3.5.3 --- Prioritized Propagation Of States (PPS) --- p.64 / Chapter 3.5.4 --- Performance Of The Proposed Enhancements --- p.66 / Chapter 3.5.5 --- Tripled Percentage Reduction Of Position RMSE When Using PPS With AWNB --- p.73 / Chapter 4 --- Autopilot For Attitude Stabilization --- p.84 / Chapter 4.1 --- Oil Test Bondi --- p.85 / Chapter 4.2 --- On Unconstrained Flight --- p.88 / Chapter 4.2.1 --- Tracking Reference Problem --- p.88 / Chapter 4.2.2 --- An Alternative To PID Attitude Control --- p.91 / Chapter 4.2.3 --- The Proposed Hierarchical PD Controller --- p.91 / Chapter 4.2.4 --- Stability Analysis --- p.92 / Chapter 4.2.5 --- Hierarchy Of The Varying Tracking Reference --- p.95 / Chapter 4.2.6 --- Asymptotical Stability And Robustness --- p.99 / Chapter 4.2.7 --- Experiment and Performance Of The Proposed Controller --- p.101 / Chapter 5 --- Avionics And Test Bench Design --- p.105 / Chapter 5.1 --- Avionics Design --- p.105 / Chapter 5.1.1 --- Design Essentials --- p.107 / Chapter 5.1.2 --- Synchronization Of Commands --- p.107 / Chapter 5.1.3 --- Normalization Of Servomechanism Commands --- p.110 / Chapter 5.2 --- Test Bench Design --- p.110 / Chapter 5.2.1 --- The Idea --- p.111 / Chapter 5.2.2 --- Concern --- p.111 / Chapter 5.2.3 --- Test Bench Design Options --- p.112 / Chapter 5.2.4 --- Building The Test Bench --- p.113 / Chapter 5.2.5 --- Disturbance In IMU Data --- p.113 / Chapter 5.2.6 --- The Solution To IMU Saturation --- p.115 / Chapter 6 --- Conclusion --- p.118 / Chapter 6.1 --- Actuation Dynamics --- p.118 / Chapter 6.2 --- State Estimation for GNSS Outage --- p.119 / Chapter 6.3 --- Hierarchical PD Controller --- p.121 / Chapter A --- Appendix - Derivation From Recursive Least Square Estimation To Kalman Filter --- p.122 / Chapter A.1 --- Recursive Least Square --- p.122 / Chapter A.1.1 --- Alternate Estimator form for RLS --- p.134 / Chapter A.1.2 --- Propagation of States and Covariance --- p.137 / Chapter A.1.3 --- Kalman Filter --- p.139 / Chapter B --- Appendix - Actuation by Gyroscopic Effect --- p.144 / Chapter B.1 --- Expression of The Induced Moment Due to Gyroscopic Effect In The Total External Moment --- p.150 / Chapter B.2 --- An Illustrated Example --- p.153 / Chapter B.3 --- Another Derivation By Using A Different Orientation Definition --- p.156 / Chapter B.4 --- Dimensions of the helicopter for experiments --- p.166 / Bibliography --- p.167

Thesis. 1977. Ph.D.--Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND AERONAUTICS. / Vita. / Includes bibliographical references. / Ph.D.

No description available.

A theoretical investigation of the asymmetry of induced flow in the vicinity of a lifting rotor in forward flight has been conducted. The analysis is based upon an asymmetric wake which is a logical extension of that used for previous investigations. Equations for the induced velocities at an arbitrary point in space are presented in a form suitable for numerical integration. Numerical results for the normal induced velocity in the lateral plane of the rotor are presented in the form of tables and charts. Comparison with previously available measurements indicates an improvement in accuracy over older theories. The results should be useful in estimating the interference between wing and rotor of compound helicopters and convertiplanes. In addition the results should be applicable to the problem of mutual interference between rotors of multi-rotor helicopters. / Master of Science

The dissertation investigates helicopter trim and stability during level bank-angle and diving bank-angle turns. The level turn is moderate in that sufficient power is available to maintain level maneuver, and the diving turn is severe where the power deficit is overcome by the kinetic energy of descent. The investigation basically represents design conditions where the peak loading goes well beyond the steady thrust limit and the rotor experiences appreciable stall. The major objectives are: 1) to assess the sensitivity of the trim and stability predictions to the approximations in modeling stall, 2) to correlate the trim predictions with the UH-60A flight test data, and 3) to demonstrate the feasibility of routinely using the exact fast-Floquet periodic eigenvector method for mode identification in the stability analysis. The UH-60A modeling and analysis are performed using the comprehensive code RCAS (Army's Rotorcraft Comprehensive Analysis System). The trim and damping predictions are based on quasisteady stall, ONERA-Edlin vi (Equations Differentielles Lineaires) and Leishman-Beddoes dynamic stall models. From the correlation with the test data, the strengths and weaknesses of the trim predictions are presented. / by Ranjith Mohah. / Thesis (Ph.D.)--Florida Atlantic University, 2012. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2012. Mode of access: World Wide Web.