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Full-Text Articles in Engineering
Stochastic Optimal Control In Nonlinear Systems, Celestin Nkundineza
Stochastic Optimal Control In Nonlinear Systems, Celestin Nkundineza
Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research
Stochastic control is an important area of research in engineering systems that undergo disturbances. Controlling individual states in such systems is critical. The present investigation is concerned with the application of the stochastic optimal control strategy developed by To (2010) and its implementation as well as providing computed results of linear and nonlinear systems under stationary and nonstationary random excitations. In the strategy the feedback matrix is designed based on the achievement of the objectives for individual states in the system through the application of the Lyapunov equation for the system. Each diagonal element in the gain or associated gain …
Balanced Truncation Of Linear Second-Order Systems: A Hamiltonian Approach, Carsten Hartmann, Valentina-Mira Vulcanov, Christof Schutte
Balanced Truncation Of Linear Second-Order Systems: A Hamiltonian Approach, Carsten Hartmann, Valentina-Mira Vulcanov, Christof Schutte
Faculty of Engineering and Information Sciences - Papers: Part A
We present a formal procedure for structure-preserving model reduction of linear second-order and Hamiltonian control problems that appear in a variety of physical contexts, e.g., vibromechanical systems or electrical circuit design. Typical balanced truncation methods that project onto the subspace of the largest Hankel singular values fail to preserve the problem's physical structure and may suffer from lack of stability. In this paper, we adopt the framework of generalized Hamiltonian systems that covers the class of relevant problems and that allows for a generalization of balanced truncation to second-order problems. It turns out that the Hamiltonian structure, stability, and passivity …
A Continuously-Stable Linear Actuation Based On Bending Type Artificial Muscles, Rahim Mutlu, Gursel Alici
A Continuously-Stable Linear Actuation Based On Bending Type Artificial Muscles, Rahim Mutlu, Gursel Alici
Faculty of Engineering - Papers (Archive)
Electroactive polymer actuators, also known as artificial muscles, can operate both in wet and dry media under as small as 1 Volt potential difference. This paper reports on a multi-stable linear actuation mechanism articulated with artificial muscles. Kinematic and finite element analyses of the mechanism are studied to demonstrate the feasibility of the mechanism. Experiments were conducted on a real mechanism articulated with a multiple number (4 or 8) of electroactive polymer actuators, which had the dimensions of 12×2×0.17mm. The numerical and experimental results demonstrate that the angular displacement of the artificial muscles is accurately transformed into a rectilinear motion …
The Effect Of Non-Linear Mooring Stiffness On The Vortex-Induced Motion Of Cylindrical Structures, Brad Stappenbelt
The Effect Of Non-Linear Mooring Stiffness On The Vortex-Induced Motion Of Cylindrical Structures, Brad Stappenbelt
Faculty of Engineering - Papers (Archive)
Mooring systems employed for floating structures commonly result in non-linear load-excursion characteristics. The non-linear stiffness and the subsequent amplitude-dependent natural frequency influence the vortex-induced motion of the structure. The application of linear stiffness vortex-induced motion modelling and experimental data has been shown to produce significant uncertainties regarding the onset and vortex-induced response prediction of catenary moored cylindrical structures (Bjarke et al. 2003; Dijk et al. 2003). In the present study, the two-degree of freedom vortex-induced motion of non-linearly compliant elastically mounted rigid cylinders was experimentally investigated. Specifically, third-order polynomial hard-spring stiffness, typical of catenary moorings was considered. The linear and …