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Wen J.,Jiangnan University | Peng L.,Jiangnan University | Peng L.,State Key Laboratory of Digital Manufacturing Equipment and Technology | Nguang S.K.,University of Auckland
Transactions of the Institute of Measurement and Control | Year: 2014

This paper investigates the finite-time HN control problem for discrete-time Markovian jump linear systems with time delay and norm-bounded exogneous disturbance. The stochastic finite-time boundness is achieved by employing an average dwell time approach, which has more design freedom by allowing the stochastic Lyapunov-like function (SLLF) to increase more slowly during the running time of each operation mode. Note that the SLLF increases at every jumping instant rather than at every sampling time instant. Sufficient conditions for the solvability of the controller, which are dependent or independent on the time delay, are given in terms of linear matrix inequalities. Numerical examples are given to verify the efficiency of the proposed method. © The Author(s) 2014. Source


Wu T.,Huazhong University of Science and Technology | Pei X.,Huazhong University of Science and Technology | Lu Y.,Huazhong University of Science and Technology | Chen C.,Huazhong University of Science and Technology | Gao L.,State Key Laboratory of Digital Manufacturing Equipment and Technology
Journal of Network and Computer Applications | Year: 2013

With the boom of Internet Technology, it becomes possible to combine designers from different disciplines into one team to support product design globally. In this paper, a distributed collaborative product design environment is presented to support top-down process oriented product design. In conceptual design stage, the artifact is managed by semantic norm model (SNM). In SNM, the designers can define virtual components at early design stage and instantiate those components at later detailed design stage. By role-based access control (RBAC), different roles with corresponding permissions could be assigned to distributed designers, and the designers could concurrently modify different components of the product relevant to his or her roles. Based on the SNM and RBAC system, a distributed collaborative product design environment is developed and the top-down oriented product design process is demonstrated. © 2013 Elsevier Ltd. All rights reserved. Source


Yan L.,Huazhong University of Science and Technology | Yang W.,Huazhong University of Science and Technology | Yang W.,State Key Laboratory of Digital Manufacturing Equipment and Technology | Jin H.,Huazhong University of Science and Technology | Wang Z.,Huazhong University of Science and Technology
Machining Science and Technology | Year: 2012

Tool flank wear has significant effects on the cutting process, as it affects cutting forces, temperature and residual stresses. In this article, analytical models are developed to predict the cutting temperature and residual stresses in the orthogonal machining of a worn tool. In these models, measured forces, cutting conditions, tool geometry, and material properties are used as inputs. Stresses resulting from thermal stresses, fresh tool stresses and stresses due to tool flank wear are used in this analytical elasto-plastic model, and the residual stresses are determined by a relaxation procedure. The analytical model is verified experimentally with X-ray diffraction measurements. With the analytical model presented here, accurate residual stress profiles in worn tools are shown, while the computational time is significantly reduced from days, typical for finite-element method (FEM) models, to seconds. © 2012 Copyright Taylor and Francis Group, LLC. Source


Zhang X.,Shanghai University | Zhang X.,State Key Laboratory of Digital Manufacturing Equipment and Technology | Li C.,Shanghai University
Guangxue Xuebao/Acta Optica Sinica | Year: 2014

The light field imaging with microlens array is modeled through analyzing three fundamental factors, such as space, lens, and sensor. The spatial multiplexing is explained and the relationship between the light field and the pixel in raw image is described. Based on the phase shifting, a calibration method is proposed to determine the centers of microlens, the corresponding relationship between the pixel and the microlens, and the character of the microlens vignetting. The experiment is conducted on a commercial light field camera, Lytro. The light field is decoded from the raw image and the refocus image and all-focus image is created from the obtained light field. The experiment results confirm the proposed model and calibration method is valid. ©, 2014, Chinese Optical Society. All right reserved. Source


Yan L.,Huazhong University of Science and Technology | Yan L.,State Key Laboratory of Digital Manufacturing Equipment and Technology | Yang W.,Huazhong University of Science and Technology | Yang W.,State Key Laboratory of Digital Manufacturing Equipment and Technology | And 2 more authors.
International Journal of Advanced Manufacturing Technology | Year: 2012

In the machining of hard machined materials, microstructure changes in the machined surface must be taken into account to improve product performance. Therefore, a large number of experimental and finite element method investigations have been carried out to investigate these microstructure changes. However, until now, only a few studies have reported the analytical modelling of microstructure changes. This paper presents a hardness-based analytical model that accounts for both mechanical and thermal effects in predicting microstructure changes during the machining of 304 stainless steel. The model was also validated for a range of cutting speeds, feed rates, and wear widths. The predicted results are in good agreement with the experimentally measured results. Thus, with the analytical model, an accurate prediction of microstructure changes is achieved, which reduces experimental expense and finite element method computational time. © Springer-Verlag London Limited 2011. Source

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