توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱Necessity of Coupling Finite Element and Boundary Element Methods in Modeling Infinite Soil Mass
اطلاعات انتشار: هشتمین کنگره بین المللی مهندسی عمران، سال
تعداد صفحات: ۸
by coupling the finite element (FE) and the boundary element (BE) methods, their advantages can be assimilated and their deficiencies can be reduced. Based on this idea a new domain decomposition method has been used here to solve the governing equations separately in FE and BE sub–domains. Both Dirichlet and Neumann boandary conditions are assumed across the interface between the sub–domains. Solution of the governing equations over each sub–domain results in the new displacements and tractions. By imposition of equilibrium and compatibility conditions across the interface, the Neumann and Dirichlet boundary values will be updated and the computations will go on until convrgence achieved. A rigid strip footing over a linear elastic half space is considered to investigate the effect of infinite medium on the results. the area in the vicinity of the footing (near field) is simulated by the FE method and the farther surounding area (far field) is modeled by the BE method. the accoracy of proposed method is studied by the comparing the obtained results with results of the conventional FE method and closed form solution.<\div>

۲Sliding and Terminal Sliding Mode Control of a 3–Axis Flight Motion Simulator
نویسنده(ها): ، ، ،
اطلاعات انتشار: بیستمین کنفرانس مهندسی برق ایران، سال
تعداد صفحات: ۶
Flight motion simulators are used to simulate the motion of flying objects in a laboratory setting. A 3–axis flight motion simulator as a three degrees–of–freedom table is a nonlinear, multivariable system. Most research and control methods have been proposed for these types of tables are basedon linearized models of these systems and then using linear control methods. Furthermore for dealing with the problem of being multivariable, these tables are considered as a three single input–single output systems, with neglecting and minimizing coupling effects among gimbals. In this paper, unlike previous researches, we use the complete and full dynamic equations of a 3–axis flight motion simulator as a real plant, including the effect of wobble, unbalancy, missing theorthogonality of axes and gravity terms. It is also clear that because of uncertainty, robust control methods are needed.These equations are highly nonlinear and multivariable. Two nonlinear multivariable robust methods are developed fortracking and regulation purposes; include Sliding Mode and Terminal Sliding Mode controls. In the presence of external disturbances, the simulation results are presented to verify the efficiency of the proposed control systems<\div>
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