A tool for designing robust autopilots for ramjet missiles

Kahvecioğlu, Alper
The study presented in this thesis comprises the development of the longitudinal autopilot algorithm for a ramjet powered air-to-surface missile. Ramjet Missiles have short time-of-flight, however they suffer from limited angle of attack margins due to poor operational-region characteristics of the ramjet engine. Because of such limitations and presence of uncertainties involved, Robust Control Techniques are used for the controller design. Robust Control Techniques not only provide an easy limitation/uncertainty/performance handling for MIMO systems, but also, robust controllers promise stability and performance even in the presence of uncertainties of a pre-defined class. All the design process is carried out in such a way that at the end of the study a tool has been developed, that can process raw aerodynamic data obtained by Missile DATCOM program, linearize the equations of motion, construct the system structure and design sub-optimal H? controllers to meet the requirements provided by the user. An autopilot which is designed by classical control techniques is used for performance and robustness comparison, and a non-linear simulation is used for validation. It is concluded that the code, which is very easy to modify for the specifications of other missile systems, can be used as a reliable tool in the preliminary design phases where there exists uncertainties/limitations and still can provide satisfactory results while making the design process much faster.


Navigation algorithms and autopilot application for an unmanned airvehicle
Kahraman, Eren; Alemdaroğlu, Hüseyin Nafiz; Nalbantoğlu, Volkan; Department of Aerospace Engineering (2010)
This study describes the design and implementation of the altitude and heading autopilot algorithms for a fixed wing unmanned air vehicle and navigation algorithm for attitude and heading reference outputs. Algorithm development is based on the nonlinear mathematical model of Middle East Technical University Tactical Unmanned Air Vehicle (METU TUAV), which is linearized at a selected trim condition. A comparison of nonlinear and linear mathematical models is also done. Based on the linear mathematical model...
Conceptual internal design and computational fluid dynamics analysis of a supersonic inlet
Alemdaroğlu, Mine; Özyörük, Yusuf; Department of Aerospace Engineering (2005)
In this thesis, the conceptual internal design of the air inlet of a supersonic, high altitude, solid propellant ramjet cruise missile is performed. Inviscid, compressible CFD analysis of the designed inlet is made in order to obtain qualitative and quantitative performance characteristics of the inlet at different operating conditions. The conceptual design of the inlet is realized by using analytical relations and equations, correlations derived from numerous available past experimental data and state-of-...
Implementation of turbulence models on 2d hybrid grids using an explicit/implicit multigrid algorithm
Yılmaz, Ali Emre; Tuncer, İsmail Hakkı; Department of Aerospace Engineering (2011)
In this thesis study, implementation, numerical stability and convergence rate issues of turbulence modeling are explored. For this purpose, a one equation turbulence model, Spalart-Allmaras, and a two-equation turbulence model, SST k-w, are adapted to an explicit, cell centered, finite volume method based, structured / hybrid multi grid flow solver, SENSE2D, developed at TUBITAK-SAGE. Governing equations for both the flow and the turbulence are solved in a loosely coupled manner, however, each set of equat...
Numerical and experimantal analysis of flapping motion in hover, application to micro air vehicles
Kurtuluş, Dilek Funda; Alemdaroğlu, Hüseyin Nafiz; Department of Aerospace Engineering (2005)
The aerodynamics phenomena of flapping motion in hover are considered in view of the future Micro Air Vehicle applications. The aim of this work is to characterize the vortex dynamics generated by the wing in motion using direct numerical simulation and experimental analysis then to propose a simplified analytical model for prediction of the forces in order to optimize the parameters of the motion leading to maximum force. A great number of cases are investigated corresponding to different angles of attack,...
Automation and verification of Ankara wind tunnel
Katırcı, Argün; Alemdaroğlu, Hüseyin Nafiz; Department of Aerospace Engineering (2006)
All the operational and measurement systems of Ankara Wind Tunnel was modified to operate automatically under the control of a central computer system programmed using the Lab View programming language. A cruciform air-to-air missile with triangular canard control and a trapezoidal wing model was tested by a 35mm diameter internal balance at Mach 0.2 and data was compared with the test data of the same model’s test that was performed at NASA Langley Research Center.
Citation Formats
A. Kahvecioğlu, “A tool for designing robust autopilots for ramjet missiles,” M.S. - Master of Science, Middle East Technical University, 2006.