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Helicopter control and its general models (thesis)
Résumé de la thèse
Simulations on helicopters are very useful for companies and research labs when one wants to make dynamic analysis, study the trajectory, investigate air combat, prepare pilot training and do many other tasks. The problem is that, regarding helicopters, very few investigations have been conducted and very few accurate programs which model their behavior exist in the scientific literature. Recent ones focus on quite rare flights in practice, as in the work of K. Sibiliski [Sibilski 1998 Sibilski 1999] in the late 90s, or enough incomplete in their modeling as the study lead by students from MH Lowenberg [Bedford and Lowenberg 2003, Bedford and Lowenberg 2004, Rezgui et al. 2006]. Meanwhile, the National Aeronautics and Space Administration (NASA) developed a program through the software Matlab whose name is "Minimum-Complexity Helicopter Simulation Math Model" (MCHSMM). This model is a flight simulator of a helicopter and has many advantages as it relies on basic data sources and does not require powerful computer tools. So, it allows low cost real-time simulations.
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Extraits de la thèse
[...] We got the following results: Figure 50: evolution of velocities and angles for the third test The rotational velocities and as well as the Euler angles ? ? and ? are null which is relevant given the fact the helicopter is supposed to move straightly. The same statement 59 can be done for the longitudinal flapping angle and the lateral flapping angle . As for velocities, u is constant and equal to about 55 m/s (200 km/h) which is relevant with the initial conditions of the study. The velocity along the Z-axis may come from the force applied on the Z-axis and supposed to compensate the weight of the helicopter. [...]
[...] Plot from the implementation on Matlab Comparison with theory and interpretation Conclusion Helicopter noise reduction Introduction The Blade-vortex interaction Theoretical model Introduction X. Animation of the blade Explanation of some Matlab commands Results of the investigation Calculation of helicopter power Introduction Motion of the helicopter and its elements Atmospheric parameters Results and interpretation Conclusion and perspectives of the investigation Bibliography Appendix architecture of the DRA research Puma XW Appendix data issued from the book of Padfield Appendix explanation of the implementation on Matlab for the calculation of the lift coefficient Appendix determination of the motion of an helicopter System to which the Newton's laws of motion is applied Full nonlinear six-degree-of-freedom rigid body translational and rotational aircraft motion Euler rates Angular acceleration Translatory acceleration Euler angles Final rigid body equations Force and torque equations Forces Torques Model for main rotor Hovering Vertical descent Forward flight The rotor system and kinematics of a blade element (How to calculate ) Modeling for tail rotor Modeling for the empennage Appendix motors made by SAFRAN group for helicopters Abstract This document presents the theory relative to helicopters used for the implementation on Matlab. [...]
[...] Some projects have been conducted in this way but they suffer from many deficiencies as many effects have not been taken into account such as the ground effects, the wind, the atmospheric conditions Such projects would be useful for companies and for researchers to confront the performances of different helicopters and to make new ones Bibliography Padfield, G. D. [1995], Helicopter Flight Dynamics: The Theory and Application of Flying Qualities and Simulation Modeling, AIAA Educational Series. MATLAB 7.01 & Simulink 6.1 U. S. Army, [2010], Fundamentals of Flight: The Official U.S. [...]
[...] As for the evolutions of the forces along X and Z and the moment around the Y axis, their initial values seem to be relevant with what we expected. As for their evolution, the torque along the Y-axis may be created by the movement of the main one. As for the forces, the same explanation may be stated Figure 42: evolution of moments and forces on the tailplane and on the vertical fin for the first test The tailplane normal force Ztp and the pitching moment at the center of gravity Mtp follow the same evolution. [...]
[...] Thus, knowledge of the helicopter geometry, blade dynamics and other aerodynamic data which can only be got from real tests on wind-tunnel will be necessary. These tests, performed by companies, are very expensive and are often kept confidential so some information cannot be reached for this project. Nevertheless, the goal of this study is to improve the existing models (and, in our case, completely revise most of the parts) to get an even more accurate and understandable program by its user. [...]
À propos de l'auteur
Sylvain L.Manager Physique- Niveau
- Grand public
- Etude suivie
- physique
- Ecole, université
- Arts &...
Descriptif de la thèse
- Date de publication
- 2016-09-06
- Date de mise à jour
- 2016-09-06
- Langue
- anglais
- Format
- pdf
- Type
- thèse
- Nombre de pages
- 92 pages
- Niveau
- grand public
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- le comité de lecture