Flight simulation and control of a helicopter

Erçin, Gülsüm Hilal
In this thesis the development of a nonlinear simulation model of a utility helicopter and the design of its automatic flight control system is addressed. In the first part of this thesis, the nonlinear dynamic model for a full size helicopter is developed using the MATLAB/SIMULINK environment. The main rotor (composed of inflow and flapping dynamics parts), tail rotor, fuselage, vertical stabilizer, horizontal stabilizer of the helicopter are modeled in order to obtain the total forces and moments needed for the flight simulation of the helicopter. Total forces and moments are used in 6 degrees of freedom equations of motion model and helicopter states are calculated for the specified flight conditions such as hover and forward flight. Trim and linearization programs are developed. The linearized models of hover and forward flight conditions are used for the automatic flight control system design. Automatic flight control system model consists of necessary systems in order to ease the pilot control of the helicopter. A classical inner stability loop and outer flight directory mode approach is taken to design the automatic flight control system. For the inner stability loop both classical rate feedback and truncated system state feedback control approaches are used. The outer loop modes implemented are heading hold, attitude hold (pitch, roll), altitude acquire and hold mode for hover condition and heading hold, attitude hold (pitch, roll), altitude acquire and hold mode and airspeed hold for forward flight condition. Finally, the success of the controllers are demonstrated through nonlinear simulations for different flight directory modes in hover and forward flight conditions.


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Seber, Guclu; Bendiksen, Oddvar O. (American Institute of Aeronautics and Astronautics (AIAA), 2008-06-01)
A fully nonlinear aeroelastic formulation of the direct Eulerian-Lagrangian computational scheme is presented in which both structural and aerodynamic nonlinearities are treated without approximations. The method is direct in the sense that the calculations are done at the finite element level, both in the fluid and structural domains, and the fluid-structure system is time-marched as a single dynamic system using a multistage Runge-Kutta scheme. The exact nonlinear boundary condition at the fluid-structure...
Investigation of rotor wake interactions in helicopters using 3d unsteady free vortex wake methodology
Yemenici, Öznur; Uzol, Oğuz; Department of Aerospace Engineering (2010)
This thesis focuses on developing and examining the capabilities of a new in-house aerodynamic analysis tool, AeroSIM+, and investigating rotor-rotor aerodynamic interactions for two helicopters, one behind the other in forward flight. AeroSIM+ is a 3-D unsteady vortex panel method potential flow solver based on a free vortex wake methodology. Validation of the results with the experimental data is performed using the Caradonna-Tung hovering rotor test case. AeroSIM+ code is improved for forward flight cond...
Evaluation and comparison of helicopter simulation models with different fidelities
Yılmaz, Deniz; Yavrucuk, İlkay; Department of Aerospace Engineering (2008)
This thesis concerns the development, evaluation, comparison and testing of a UH-1H helicopter simulation model with various fidelity levels. In particular, the well known minimum complexity simulation model is updated with various higher fidelity simulation components, such as the Peters-He inflow model, horizontal tail contribution, improved tail rotor model, control mapping, ground e ect, fuselage interactions, ground reactions etc. Results are compared with available flight test data. The dynamic model ...
Tilt duct vertical takeoff and landing uninhabited aerial vehicle concept design study
Armutcuoglu, O; Kavsaoglu, MS; Tekinalp, Ozan (American Institute of Aeronautics and Astronautics (AIAA), 2004-03-01)
A new autonomously controlled tilt-duct vertical takeoff and landing uninhabited aerial vehicle concept is proposed. This design combines the vertical flight capability of a helicopter and forward flight performance of a fixed-wing conventional aircraft. The two main engines and propellers are located inside the tilting ducts attached to the wing tips. There is a third engine-propeller combination located inside the all fuselage for pitch and yaw control during hover and transition. The advantages and disad...
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Ekinci, Özgür; Yavrucuk, İlkay; Department of Aerospace Engineering (2009)
Varying missile configurations may create uncertainty for a missile control algorithm developed with linear control theory, for instance the control system performance requirements may not be satisfied anymore. Missile configuration may change during the missile design period due to variations in subsystem locations, subsystem weights and missile geometry. Likewise, burning propellant, deployment of aerodynamic surfaces and wings with varying sweep angle can be considered as in-flight missile configuration ...
Citation Formats
G. H. Erçin, “Flight simulation and control of a helicopter,” M.S. - Master of Science, Middle East Technical University, 2008.