Motion simulation of annular polishing

Based on the Coulomb friction model, the frictional motion model of workpiece relating to the polishing pad was presented in annular polishing. By the dynamic analysis software, the model was simulated and analysed. The conclusions from the results were that the workpiece did not rotate steadily. When the angular velocity of ring and the direction were the same as that of the polishing pad, the angular velocity of workpiece hoicked at the beginning and at the later stage were the same as that of the polishing pad before contacting with the ring. The angular velocity of workpiece vibrated at the moment of contacting with the ring. After that the angular velocity of workpiece increased gradually and fluctuated at a given value, while the angular velocity of ring decreased gradually and also fluctuated at a given value. Since the contact between the workpiece and the ring was linear, their linear velocities and directions should be the same. But the angular velocity of workpiece was larger than that of the polishing pad on the condition that the radius of the workpiece was less than that of the ring. This did not agree with the pure translation principle and the workpiece surface could not be flat, either. Consequently, it needed to be controlled with the angular velocity of ring and the radii of the ring and the workpiece, besides friction to make the angular velocity of workpiece equal to that of the polishing pad for obtaining fine surface flatness of the workpiece. Copyright © 2007 Inderscience Enterprises Ltd.}

基于拓展LIMD算法的智能动态几何软件设计

几何约束求解技术是新一代智能化参数化CAD的核心技术之一,是CAD领域的一个前沿课题.其目的是提供工程图形的自动求解,其主要特点是:自由拖动元素、动态图形生成、动态测量、动态轨迹生成.UMD是约束求解中一个应用较广的算法,作者对该算法进行了拓宽和改进,提出了具体解决方法,并得到了较好结果.

基于功率跟踪控制策略的带式输送机动态设计方法

在带式输送机动态过程仿真的基础上 ,以多驱动带式输送机系统为对象 ,对可控多驱动系统进行动力学分析·采用基于功率跟踪的方法 ,在合理的启动曲线的基础上 ,将第一驱动按合理启动曲线启动 ,其他驱动顺次跟踪第一驱动功率的控制策略·基于有限元方法建立了系统的动力学方程 ,提出了可控启动过程的动态分析算法 ,开发了动态设计软件BCD 2 0 ,通过对实际系统的仿真 ,证明了算法和软件的正确性·

带式输送机停机动态过程的计算机仿真

研究了带式输送机停机过程的动态设计 ,通过分析提出了输送机停机过程的力学模型为两种 :第 1模型与启动过程的力学模型相同 ,第 2模型为具有固定端的振动模型·分析了制动力的传动机理 ;在综合各种停机方式的基础上给出了停机过程的分类 ,提出了控制速度停机、自由停机和制动停机的计算方式及其计算方法 ;开发了带式输送机动态分析软件BCD .2 0的停机计算部分 ;应用软件对停机过程进行仿真研究 ,对停机过程进行了分析 ;给出了停机过程的动态设计方法和拉紧装置行程的计算式 ;得出了不同的停机方式结束后输送带的张力分布是不同的结果·所提出的方法可用于大型带式输送机停机过程的合理设计 ,避免事故的发生

Research on Dynamic Micro-Deformation under Laser Point Source

The dynamic micro-deformation of the specimen under laser point source is measured using a laser beam reflex amplifier system and numerically simulated by Msc.Marc software. Compared with experimental result and calculated result, the final deformation direction of the specimen depends on the result of the thermal strain and the phase transformation strain cooperation, away from the laser beam or towards the laser beam, the final deformation angle depends on temperature gradient in the thickness direction and the geometry constraint of the specimen. The conclusion lays the foundation for further research on the mechanism of laser bending. At the same time, it is proposed that the model of calculation based on classical Fourier heat transfer theory cannot be enough to simulate the dynamic micro-deformation of the specimen under laser point source, the model of calculation should be modified in the future.

Chaotic dynamic analysis of viscoelastic plates

The dynamic buckling of viscoelastic plates with large deflection is investigated in this paper by using chaotic and fractal theory. The material behavior is given in terms of the Boltzmann superposition principle. in order to obtain accurate computation results, the nonlinear integro-differential dynamic equation is changed into an autonomic four-dimensional dynamical system. The numerical time integrations of equations are performed by using the fourth-order Runge-Kutta method. And the Lyapunov exponent spectrum, the fractal dimension of strange attractors and the time evolution of deflection are obtained. The influence of geometry nonlinearity and viscoelastic parameter on the dynamic buckling of viscoelastic plates is discussed.

High dimensional imagery geometry and it's applications

Because of information digitalization and the correspondence of digits and the coordinates, Information Science and high-dimensional space have consanguineous relations. With the transforming from the information issues to the point analysis in high-dimensional space, we proposed a novel computational theory, named High dimensional imagery geometry (HDIG). Some computational algorithms of HDIG have been realized using software, and how to combine with groups of simple operators in some 2D planes to implement the geometrical computations in high-dimensional space is demonstrated in this paper. As the applications, two kinds of experiments of HDIG, which are blurred image restoration and pattern recognition ones, are given, and the results are satisfying.

Information geometry theory of high-dimension space and application for speaker independent continuous digit speech recognition

In the light of descriptive geometry and notions in set theory, this paper re-defines the basic elements in space such as curve and surface and so on, presents some fundamental notions with respect to the point cover based on the High-dimension space (HDS) point covering theory, finally takes points from mapping part of speech signals to HDS, so as to analyze distribution information of these speech points in HDS, and various geometric covering objects for speech points and their relationship. Besides, this paper also proposes a new algorithm for speaker independent continuous digit speech recognition based on the HDS point dynamic searching theory without end-points detection and segmentation. First from the different digit syllables in real continuous digit speech, we establish the covering area in feature space for continuous speech. During recognition, we make use of the point covering dynamic searching theory in HDS to do recognition, and then get the satisfying recognized results. At last, compared to HMM (Hidden Markov models)-based method, from the development trend of the comparing results, as sample amount increasing, the difference of recognition rate between two methods will decrease slowly, while sample amount approaching to be very large, two recognition rates all close to 100% little by little. As seen from the results, the recognition rate of HDS point covering method is higher than that of in HMM (Hidden Markov models) based method, because, the point covering describes the morphological distribution for speech in HDS, whereas HMM-based method is only a probability distribution, whose accuracy is certainly inferior to point covering.

Computational information geometry and its applications

Digitization is the main feature of modern Information Science. Conjoining the digits and the coordinates, the relation between Information Science and high-dimensional space is consanguineous, and the information issues are transformed to the geometry problems in some high-dimensional spaces. From this basic idea, we propose Computational Information Geometry (CIG) to make information analysis and processing. Two kinds of applications of CIG are given, which are blurred image restoration and pattern recognition. Experimental results are satisfying. And in this paper, how to combine with groups of simple operators in some 2D planes to implement the geometrical computations in high-dimensional space is also introduced. Lots of the algorithms have been realized using software.

Dynamic Measurement System for Dipoles of RCS for CS

A dynamic measurement system was developed by the Institute of Modern Physics (IMP) for the dipole prototype of Rapid Cycle Synchrotron (RCS) of China Spallation Neutron Source (CSNS). The repetition frequency of RCS is 25 Hz. The probe is a moving arc searching-coil, and the data acquisition system is based on the dynamic analysis modular of National Instrument. To get the error of high order harmonics of the field at basic frequency, the hardware integrator is replaced by a high speed ADC with software filter and integrator. A series of harmonic coefficients of field are used to express the varieties of dynamic fields in space and time simultaneously. The measurement system has been tested in Institute of High Energy Physics (IHEP), and the property of the dipole prototype of RCS has been measured. Some measurement results and the repeatability of system are illustrated in this paper.

a dynamic model to handle defect-oriented processes

Tongji Univ, Inst Dev Study, Syst Engn Soc China, Comm Syst Dynam, Syst Dynam Soc, China Chapter, Shanghai Inst Foreign Trade, Syst Dynam Soc, Chapters Asia Pacific Area