The Experts below are selected from a list of 43482 Experts worldwide ranked by ideXlab platform
Yung C. Shin - One of the best experts on this subject based on the ideXlab platform.
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Observer-Based Adaptive Robust Control of Friction Stir Welding Axial Force
IEEE ASME Transactions on Mechatronics, 2011Co-Authors: Tyler A. Davis, Yung C. ShinAbstract:Friction stir welding (FSW) is a relatively new and promising joining process that is the subject of much current research. When welding with constant parameters, the Axial Force can vary significantly due to changes in workpiece temperature and other process variations. These variations produce welds with inconsistent microstructure and tensile strength. Control of the Axial weld Force is desirable to improve the weld quality. In this paper, an observer-based adaptive robust control (ARC) approach for the Axial Force of FSW is presented to overcome process disturbances and model errors stemming from the simplistic dynamic models suitable for control. Some correlation is shown between spindle power and Axial Force, allowing readily available power measurements to be used for feedback. A model of the Axial Force is developed as a combination of a nonlinear static gain and linear dynamics. An Axial Force controller is constructed using the ARC approach and estimated state feedback from the adaptive divided difference filter (ADDF). Verification experiments are conducted on a vertical milling machine configured for FSW using an open architecture controller. The combined ARC/ADDF technique is shown to dramatically reduce Axial Force variations in the presence of significant process disturbances.
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observer based adaptive robust control of friction stir welding Axial Force
International Conference on Advanced Intelligent Mechatronics, 2010Co-Authors: Tyler A. Davis, Yung C. Shin, Bin YaoAbstract:Friction stir welding (FSW) is a relatively new and promising joining process that is the subject of much current research. With constant welding parameters the Axial Force can vary significantly due to changes in workpiece temperature and other process variations, producing welds with inconsistent microstructure and tensile strength. Control of the Axial weld Force is desirable to improve the weld quality. In this work an observer-based adaptive robust control (ARC) approach for the Axial Force of FSW is used to overcome process disturbances and model errors stemming from the simplistic dynamic models suitable for control. Good correlation is shown between spindle power and Axial Force, allowing readily available power measurements to be used for feedback. A model of the Axial Force is developed as a combination of a nonlinear static gain and linear dynamics. A Force controller is constructed using the ARC approach and estimated state feedback from the adaptive divided difference filter (ADDF). Verification experiments are conducted on a vertical milling machine configured for FSW using an open architecture controller. The combined ARC/ADDF technique is shown to dramatically reduce Axial Force variations.
Lina Xian - One of the best experts on this subject based on the ideXlab platform.
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load capacity of corroded welded hollow spherical joints subjected to bending moment and Axial Force
Journal of building engineering, 2019Co-Authors: Zhongwei Zhao, Bing Liang, Lina XianAbstract:Abstract Welded hollow spherical joints (WHSJs) have been extensively used in space lattice structures. Corrosion is inevitable in the service life of WHSJs, and it can significantly reduce their load capacity and seriously threaten their structural safety. A series of nonlinear numerical analyses was conducted to investigate the moment and Axial Force interaction for corroded WHSJs. The moment-rotation surface of corroded WHSJs subjected to Axial Force was derived. The influence of the location, size, and thickness of corrosion of WHSJs on their compressive capacity were revealed in this study. Two types of corroded shapes were investigated. Results indicate that the geometrical parameters exert a significant influence on the moment and Axial Force interaction. An analytical equation has been proposed to quantify the influence of Axial Force on the bending stiffness and moment capacity of corroded WHSJs.
Jiashi Yang - One of the best experts on this subject based on the ideXlab platform.
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an analysis of the extension of a zno piezoelectric semiconductor nanofiber under an Axial Force
Smart Materials and Structures, 2017Co-Authors: Chunli Zhang, Weiqiu Chen, Xiaoyuan Wang, Jiashi YangAbstract:This paper presents a theoretical analysis on the Axial extension of an n-type ZnO piezoelectric semiconductor nanofiber under an Axial Force. The phenomenological theory of piezoelectric semiconductors consisting of Newton's second law of motion, the charge equation of electrostatics and the conservation of charge was used. The equations were linearized for small Axial Force and hence small electron concentration perturbation, and were reduced to one-dimensional equations for thin fibers. Simple and analytical expressions for the electromechanical fields and electron concentration in the fiber were obtained. The fields are either totally or partially described by hyperbolic functions relatively large near the ends of the fiber and change rapidly there. The behavior of the fields is sensitive to the initial electron concentration and the applied Axial Force. For higher initial electron concentrations the fields are larger near the ends and change more rapidly there.
Tyler A. Davis - One of the best experts on this subject based on the ideXlab platform.
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Observer-Based Adaptive Robust Control of Friction Stir Welding Axial Force
IEEE ASME Transactions on Mechatronics, 2011Co-Authors: Tyler A. Davis, Yung C. ShinAbstract:Friction stir welding (FSW) is a relatively new and promising joining process that is the subject of much current research. When welding with constant parameters, the Axial Force can vary significantly due to changes in workpiece temperature and other process variations. These variations produce welds with inconsistent microstructure and tensile strength. Control of the Axial weld Force is desirable to improve the weld quality. In this paper, an observer-based adaptive robust control (ARC) approach for the Axial Force of FSW is presented to overcome process disturbances and model errors stemming from the simplistic dynamic models suitable for control. Some correlation is shown between spindle power and Axial Force, allowing readily available power measurements to be used for feedback. A model of the Axial Force is developed as a combination of a nonlinear static gain and linear dynamics. An Axial Force controller is constructed using the ARC approach and estimated state feedback from the adaptive divided difference filter (ADDF). Verification experiments are conducted on a vertical milling machine configured for FSW using an open architecture controller. The combined ARC/ADDF technique is shown to dramatically reduce Axial Force variations in the presence of significant process disturbances.
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observer based adaptive robust control of friction stir welding Axial Force
International Conference on Advanced Intelligent Mechatronics, 2010Co-Authors: Tyler A. Davis, Yung C. Shin, Bin YaoAbstract:Friction stir welding (FSW) is a relatively new and promising joining process that is the subject of much current research. With constant welding parameters the Axial Force can vary significantly due to changes in workpiece temperature and other process variations, producing welds with inconsistent microstructure and tensile strength. Control of the Axial weld Force is desirable to improve the weld quality. In this work an observer-based adaptive robust control (ARC) approach for the Axial Force of FSW is used to overcome process disturbances and model errors stemming from the simplistic dynamic models suitable for control. Good correlation is shown between spindle power and Axial Force, allowing readily available power measurements to be used for feedback. A model of the Axial Force is developed as a combination of a nonlinear static gain and linear dynamics. A Force controller is constructed using the ARC approach and estimated state feedback from the adaptive divided difference filter (ADDF). Verification experiments are conducted on a vertical milling machine configured for FSW using an open architecture controller. The combined ARC/ADDF technique is shown to dramatically reduce Axial Force variations.
Zhongwei Zhao - One of the best experts on this subject based on the ideXlab platform.
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load capacity of corroded welded hollow spherical joints subjected to bending moment and Axial Force
Journal of building engineering, 2019Co-Authors: Zhongwei Zhao, Bing Liang, Lina XianAbstract:Abstract Welded hollow spherical joints (WHSJs) have been extensively used in space lattice structures. Corrosion is inevitable in the service life of WHSJs, and it can significantly reduce their load capacity and seriously threaten their structural safety. A series of nonlinear numerical analyses was conducted to investigate the moment and Axial Force interaction for corroded WHSJs. The moment-rotation surface of corroded WHSJs subjected to Axial Force was derived. The influence of the location, size, and thickness of corrosion of WHSJs on their compressive capacity were revealed in this study. Two types of corroded shapes were investigated. Results indicate that the geometrical parameters exert a significant influence on the moment and Axial Force interaction. An analytical equation has been proposed to quantify the influence of Axial Force on the bending stiffness and moment capacity of corroded WHSJs.
