检索结果-内蒙古大学图书馆

Collection of Technical Papers - 10th AIAA/ISSMO Multidisciplinary Analysis and Optimization Conference

作者： Wang, Michael Yu Zhou, Shiwei Department of Automation and Computer-Aided Engineering Chinese University of Hong Kong Shatin NT Hong Kong

ISBN: (纸本)1563477165

In this paper we present a phase-field method to the problem of shape and topology synthesis of structures with three materials. A single phase model is developed based on the classical phase-transition theory in the fields of mechanics and material sciences. The multi-material synthesis is formulated as a continuous optimization problem within a fixed reference domain. As a single parameter, the phase-field model represents regions made of any of the three distinct material phases and the interface between the regions. The Van der Waals-Cahn-Hilliard theory is applied to define a dynamic process of phase transition. The Γ-convergence theory is used for an approximate numerical solution to this free-discontinuity problem without any explicit tracking of the interface. Within this variational framework, we show that the phase-transition theory leads to a well-posed problem formulation with the effects of "domain regularization" and "region segmentation" incorporated naturally. The proposed phase-field method is illustrated with several 2D examples that have been extensively used in the recent literature of topology optimization, especially in the homogenization based methods. It is further suggested that such a phase-field approach may ‡ represent a promising alternative to the widely-used homogenization models for the design of heterogeneous materials and solids, with a possible extension to a general model of multiple material phases. Copyright © 2004 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

关键词： Structural analysis

来源：评论

学校读者我要写书评

暂无评论

A robust technique for structure from planar motion using image sequences

A robust technique for structure from planar motion using im...

引用

ICIA 2005: 2005 International Conference on Information Acquisition

作者： Tai, Chen Liu, Yun-Hui Department of Automation and Computer-Aided Engineering Chinese University of Hong Kong Hong Kong Hong Kong

ISBN: (纸本)0780393031

This paper proposes a robust method for recovery of motion and structure from two image sequences taken by stereo cameras undergoing a planar motion. The feature correspondence between images are extracted and refined automatically by the relation of the stereo cameras and the property of the motion. To improve the robustness, the random sample consensus (RANSAC) algorithm is adopted in the motion and structure estimation. Unlike other researchers to recover of epipolar geometry, here we use it to recover the 2D motion and to exclude the outliers not only out of the epipolar lines but also in them. Also the spirit of RANSAC is used in structure estimation to exclude the outlier from the sequence view. The most important contribution of this work is a way to make this estimation scheme more robust and efficient so as to be used in real applications. The experiments indoor and outdoor have been done to verify the feasibility of the algorithm. The results show the algorithm is robust and efficient for applications in planar motion. © 2005 IEEE.

关键词： Motion compensation

来源：评论

学校读者我要写书评

暂无评论

Generating spiral paths for sculptured surfaces machining

Generating spiral paths for sculptured surfaces machining

引用

2006 ASME International Design engineering Technical Conferences and computers and Information In engineering Conference, DETC2006

作者： Yao, Zhiyang Department of Automation and Computer-Aided Engineering Chinese University of Hong Kong Hong Kong Hong Kong

ISBN: (纸本)079183784X

To machine sculptured surfaces, ball end mills are mainly used to reach the final surface finish requirements. During machining, the cusp height is one of the major factors defining the final surface finish smoothness. A cutter path that maintains a high cutting efficiency as well as a constant cusp height is desired. Spiral curves, with the property of not requiring extra linkage segments between two adjacent arms can be used to generate a smooth cutter path. In this paper, a geometric algorithm for generating spiral cutter paths for ball end milling in machining sculptured surfaces is presented. Copyright © 2006 by ASME.

关键词： Machining

来源：评论

学校读者我要写书评

暂无评论

Image segmentation via brittle fracture mechanics

Image segmentation via brittle fracture mechanics

引用

2004 International Conference on Image Processing, ICIP 2004

作者： Wang, Wei Chung, Ronald Department of Automation and Computer-Aided Engineering Chinese University of Hong Kong Hong Kong Hong Kong

Brittle material like ceramic and rock has the nature that it is hard to crack, but if it is to crack it will crack into not dangling pieces, but separate pieces whose boundaries are contours that link up positions of strong stress in a continuous and often smooth fashion. Image segmentation desires similar results: it is to partition the image so that each partition corresponds to a separate surface or object in the imaged scene, whose boundaries are continuous and often smooth contours with a dense concentration of large intensity gradients. This work explores the adaptation of brittle fracture mechanics model toward image segmentation. An image is regarded as a plate experiencing brittle fracture when external forces are exerted on it according to intensity gradient distribution in the image. Stress concentration due to the external forces, and its change over time due to changing crack distribution are what determine the development of cracks. Real image results indicate that the model is promising. © 2004 IEEE.

关键词： Image segmentation

来源：评论

学校读者我要写书评

暂无评论

Application of support vector machine based fault diagnosis 15th

Application of support vector machine based fault diagnosis

引用

15th World Congress of the International Federation of Automatic Control, 2002

作者： Ge, Ming Zhang, Guicai Du, Ruxu Xu, Yangsheng Department of Automation and Computer-Aided Engineering Chinese University of Hong Kong Hong Kong Hong Kong

ISBN: (纸本)9783902661746

The fault diagnosis is important in continuously monitoring the performance and quality of manufacturing processes. Overcoming the drawbacks of threshold approach, artificial neural network may extract the symptom of the faults through learning from the samples, but it is difficult to design its structure. Moreover, it needs a large numbers of samples in practice. In this paper, support vector machine approach was proposed to overcome these limitations based on statistics learning theory, and a new fault diagnosis system is developed. The experimental results showed that it is an efficient and practical on-line intelligent monitoring system for the stamping processes. Copyright © 2002 IFAC.

关键词： Fault detection

来源：评论

学校读者我要写书评

暂无评论

Finding cutter engagement for ball end milling of tessellated free-form surfaces

Finding cutter engagement for ball end milling of tessellate...

引用

DETC2005: ASME International Design engineering Technical Conferences and computers and Information in engineering Conference

作者： Yao, Zhiyang Department of Automation and Computer-Aided Engineering Chinese University of Hong Kong Hong Kong Hong Kong

ISBN: (纸本)0791847403

In fabricating free-form surfaces, ball end mills are mainly used to reach the final surface finish requirements. In the milling processes, cutter engagement value measures what portion of the cutter is involved in machining at a given instant of time. This paper presents geometric algorithms for estimating cutter engagement values for ball end milling processes of tessellated free-form surfaces. The cutter engagement value calculated here can be used later on in generating efficient cutter paths, as well as performing adaptive feed rate controls. Copyright © 2005 by ASME.

关键词： Ball milling

来源：评论

学校读者我要写书评

暂无评论

Nonlinear discrete-time robust output regulation problem

Nonlinear discrete-time robust output regulation problem

引用

作者： Lan, Weiyao Huang, Jie Department of Automation and Computer-Aided Engineering Chinese University of Hong Kong Hong Kong Hong Kong

ISBN: (纸本)008045108X

in this paper, we will establish a framework that can convert a robust output regulation problem for discrete-time nonlinear systems into a robust stabilization problem for an appropriately augmented system consisting of the given plant and a specific dynamic system called internal model. We then apply this framework to solve the local robust output regulation problem for a general class of discrete-time nonlinear systems. The results of this paper gives a discrete-time counterpart of the recent results on the continuous-time robust output regulation problem. Copyright © 2005 IFAC.

关键词： Stabilization

来源：评论

学校读者我要写书评

暂无评论

Parametric shape and topology optimization with radial basis functions

Parametric shape and topology optimization with radial basis...

引用

IUTAM Symposium on Topological Design Optimization of Structures, Machines and Materials: Status and Perspectives

作者： Wang, Michael Yu Wang, Shengyin Department of Automation and Computer-Aided Engineering Chinese University of Hong Kong Shatin NT Hong Kong

ISBN: (纸本)1402047290

This paper describes a parametric optimization technique for shape and topology optimization. The proposed method is a generalization of the classical method of level sets which are represented with discrete grids. In using radial basis functions (RBFs), the proposed formulation projects the geometric motion of the level sets of an implicit function onto its parametric representation. The resulting method provides a set of new capabilities for general shape and topology optimization, particularly treating it as a parameter problem with the RBF implicit models. Numerical examples are presented in the paper, suggesting the potential of the method. © 2006 Springer.

关键词： Numerical methods

来源：评论

学校读者我要写书评

暂无评论

Dynamic balance control of multi-arm free-floating space robots

引用

International Journal of Advanced Robotic Systems 2005年第2期2卷 117-124页

作者： Huang, Panfeng Xu, Yangsheng Liang, Bin Department of Automation and Computer-Aided Engineering Chinese University of Hong Kong Hong Kong Hong Kong Shenzhen Space Technology Center Harbin Institute of Technology Shenzhen China

This paper investigates the problem of the dynamic balance control of multi-arm free-floating space robot during capturing an active object in close proximity. The position and orientation of space base will be affected during the operation of space manipulator because of the dynamics coupling between the manipulator and space base. This dynamics coupling is unique characteristics of space robot system. Such a disturbance will produce a serious impact between the manipulator hand and the object. To ensure reliable and precise operation, we propose to develop a space robot system consisting of two arms, with one arm (mission arm) for accomplishing the capture mission, and the other one (balance arm) compensating for the disturbance of the base. We present the coordinated control concept for balance of the attitude of the base using the balance arm. The mission arm can move along the given trajectory to approach and capture the target with no considering the disturbance from the coupling of the base. We establish a relationship between the motion of two arm that can realize the zeros reaction to the base. The simulation studies verified the validity and efficiency of the proposed control method.

关键词： Robots

来源：评论

学校读者我要写书评

暂无评论

Kinematic control and obstacle avoidance for redundant manipulators using a recurrent neural network

引用

International Conference on Artificial Neural Networks, ICANN 2001

作者： Tang, Wai Sum Lam, Cherry Miu Ling Wang, Jun Department of Automation and Computer-Aided Engineering The Chinese University of Hong Kong Shatin New Territories Hong Kong

ISBN: (纸本)3540424865

In this paper, a recurrent neural network called the Lagrangian network is applied for obstacle avoidance in kinematically redundant manipulators. Conventional numerical methods implemented in digital computers for obstacle avoidance redundancy resolution calculation could only compute the solution in milliseconds while neural network realized by hardware could complete the computation in microseconds, which is more desirable in real-time control of manipulators. By giving the desired end-effector velocities and the obstacle location, the neural network could generate the joint velocity vector which drives the manipulator to avoid obstacles and tracks the desired end-effector trajectory simultaneously. Simulation results show that the neural network is capable of computing the redundancy resolution for obstacle avoidance. © Springer-Verlag Berlin Heidelberg 2001.

关键词： Recurrent neural networks

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：