Leo satellites: attitude determination and control components; some linear attitude control techniques

Kaplan, Ceren
In this thesis, application of linear control methods to control the attitude of a Low-Earth Orbit satellite is studied. Attitude control subsystem is first introduced by explaining attitude determination and control components in detail. Satellite dynamic equations are derived and linearized for controller design. Linear controller and linear quadratic regulator are chosen as controllers for attitude control. The actuators used for control are reaction wheels and magnetic torquers. MATLAB-SIMULINK program is used in order to simulate satellite dynamical model (actual nonlinear model) and controller model. In simulations, the satellite parameters are selected to be similar to the actual BILSAT-1 satellite parameters. In conclusion, simulations obtained from different linear control methods are compared within themselves and with nonlinear control methods, at the same time with that obtained from BILSAT-1 satellite log data.


Leo satellites : dynamic modelling, simulations and some nonlinear attitude control techniques
Karataş, Soner; Kocaoğlan, Erol; Department of Electrical and Electronics Engineering (2006)
In this thesis nonlinear control method techniques are investigated to control the attitude of Low Earth Orbit satellites. Nonlinear control methods are compared with linear control methods. Simulations are done using Matlab and Simulink software and BILSAT-1 parameters are used in the simulations. Reaction wheels are used as the actuator.
Attitude control of multiple rigid body spacecraft with flexible hinge joints
Akbulut, Burak; Özgören, Mustafa Kemal; Department of Mechanical Engineering (2009)
Control algorithm is developed for a satellite with flexible appendages to achieve a good pointing performance. Detailed modeling activity was carried out that consists of sensor and actuator models, disturbances and system dynamics. Common hardware found in the spacecraft such as reaction wheels, gyroscopes, star trackers etc. were included in the model. Furthermore, the Newton-Euler method is employed for the derivation of multi-body equations of motion. Evaluation of the pointing accuracy with proper poi...
Experimental and computational study of scalar modes in a periodic laminar flow
Başkan Perçin, Özge; Metcalfe, Guy; Clercx, Herman J. H. (2015-10-01)
Scalar fields can evolve complex coherent structures under the action of periodic laminar flows. This comes about from the competition between chaotic advection working to create structure at ever finer length scales and diffusion working to eliminate fine scale structure. Recently analysis of this competition in terms of spectra of eigenfunctions of the advection diffusion equation (ADE) has proven fruitful because these spectra contain both fundamental information about how mixing processes create emergen...
Numerical solution of one dimensional detonation tube with reactive euler equations using high resolution method
Ungun, Yiğit; Akmandor, İbrahim Sinan; Department of Aerospace Engineering (2012)
In this thesis, numerical simulation of one dimensional detonation tube problem is solved with finite rate chemistry. For the numerical simulation, Euler equations have been used. Since detonation tube phenomena occurs in high speed flows, viscosity e ects and gravity forces are negligible. In this thesis, Godunov type methods have been studied and afterwards high resolution method is used for the numerical solution of the detonation tube problem. To solve the chemistry aspect of the problem ZND theory have...
H₂/H∞ mixed robust controller synthesis for a fin actuation system
Ölçer, Tuncay Uğurlu; Balkan, Raif Tuna; Platin, Bülent Emre; Department of Mechanical Engineering (2013)
In fin actuation systems, the performance of classical linear control systems is not satisfactory due to uncertainty of the system parameters and disturbances of the working medium. For this reason, sliding mode, H2 or H∞ robust controllers are widely used in literature for such systems. However, use of such controllers results in very conservative system responses. Based on this fact, in this thesis, development of a more effective robust controller is aimed via integration of the optimum properties of the...
Citation Formats
C. Kaplan, “Leo satellites: attitude determination and control components; some linear attitude control techniques,” M.S. - Master of Science, Middle East Technical University, 2006.