Electromechanical coupling experimental analysis of permanent magnet AC servo precision drive system

To research the dynamic characteristics of the permanent magnet AC servo precision drive system coupled with multi-factors, the experiment system is constructed with PMAC as the core and IPC as the support platform. Through software prototype system, response signals such as the current, speed and torque are acquired when the system is in the no-load and in the loading operating state, then the theoretical analysis results are compared with the experimental results. So the experiment validates that the electromechanical coupling analysis of the system is correct. This research helps to analyze the influence mechanism and law that the design parameters and electromechanical coupling parameters exerted on the system performance. At the same time, the research is beneficial for dynamic design of the permanent magnet AC servo precision drive system.     

Modeling and Simulation Analysis of the Electromechanical Coupling Facts about Precision Transmission System

Electro-mechanical coupling facts about transmission system influence dynamic characteristic and response characteristic of servo system. The coupling factors of precision transmission system are put forward, and the modelling methods of electro-mechanical system are analyzed. Based on the large-scale precise horizontal machining center, the dynamic chart of servo feed system is gained through analyzing mathematical model of the taehes, and the influence on transmission stiffness and transmission error is simulated in precision transmission system. Through changing parameters in servo feed system, the influence on dynamic characteristic and response characteristic is analyzed, so it provides a mathematical model for parameter optimization.     

Theory and Testing Research on Realizing Two-dimension Precision Adjustment with Double Eccentric Mechanism

This paper introduces the structure and operating principle of double eccentric mechanism used in a special environment to realize the two-dimension precision adjustment, establishes its precise mathematic model, analyzes the theory model with simulation model, and researches it by test. All of which indicate that the operating principle and mathematic model of double eccentric two-dimension precision adjustment mechanism are right. Under the condition of some processing and control accuracy, the adjusting error can satisfy the requirement. Through analyzing on the test data, it shows the circular degree and eccentric errors are the main sources of adjusting errors.     

Dynamics research of wind turbine gearbox with herringbone planetary gear

Based on the method of gear system dynamics and Lagrange equation, a translational-rotational coupling dynamic model of the herringbone planetary gear sets is built and dynamic analysis is carried out. The analysis results have guiding meanings for the design of herringbone planetary gear transmission system. Herringbone gear is treated as two helical gears in the model, and gear train elastic coupling, load inertia and stagger angle between the left and right helical gears is considered. The load sharing coefficients of the system are obtained through calculation, and the impact of stagger angle and coupling torsional stiffness between the left and the right helical gears on the load sharing characteristic is analyzed. The analysis results show that when stagger angle is π/2, the load sharing coefficients are the best, and coupling torsional stiffness between the left and the right helical gears has litter influence on the load sharing coefficients.     

Dynamical coupling characteristics of large marine gearbox transmission system

Taking the coupling interaction between transverse vibration and torsional vibration of input and output end into account, a transverse torsional coupling dynamic analysis model of triple geared drive system of large marine gearbox is established and dynamical coupling equations of transmission system is built according to energy based Lagrance Law. The natural characteristic and dynamic response of this drive system are analyzed using MATLAB software. The result shows that there’s no resonance phenomenon in the system, it has a good dynamic performance and operates almost periodically under the current operating load.     

Design of a 2 DOF spatial linkage mechanism

A 3D model of a 2 DOF spatial linkage mechanism was built using ADAMS. Kinematic analysis and simulation of the model were performed. The analysis results show that this mechanism meets the design requirements, which provides the basis for further design and control of the mechanism. The main factors that have an impact on mechanism precision subsequently were analyzed and designed. The results show that the sensitivity of the two legs' lengths ranks higher than that of the other design variables. Therefore, the precision design of the bipod is the key point to achieve mechanism precision. The study provides a theoretical foundation for the design, manufacture, assembly, and control of the mechanism.     

Modal Shape Analysis Methods of Machine Structure

The iterative Lanczos-reduce method for sensitivity analysis, the Guyan condensed method and the iterative synchronous vector methods in finite element modal are studied in order to solve the dynamic characteristic of complicated machine system. The primary reasons influenced on calculation precision are pointed out. The principia of master freedom for Guyan condensed method are put forward. The calculation precision of three methods is compared with the same standard finite element model. The iterative Lanczos-reduce method for sensitivity analysis is proved to be optimum analysis and the eigenvalue of arm in work device of hydraulic excavator in finite element model is solved with iterative Lanczos-reduce method for sensitivity analysis. The theory basis is provided for reasonable choose to solve the dynamic of complicated machine structure.     

Analysis of nonlinear dynamic characteristics of the Schmidt offset coupling

Considering the coupling interaction between transverse vibration and torsional vibration of the system,a dynamic analysis model of the Schmidt offset coupling is established by the method of concentrated parameter and the dynamic equation of this system is deduced by the Newton method. Considering the effect of engine and error excitations on the transmission system,the Gill numerical solution method is used to study the dynamic response of the drive system. The results show that it has a good dynamic performance and its vibration belongs to almost periodic vibration,which provides theoretical guidance for further dynamic performance optimization and engineering application.     

A four-compartment computer virus propagation model with graded infection rate

A new resident virus propagation model with graded infection rate is established based on the properties of two important stages undergoing by resident virus, which are the latent phase, in which resident virus cannot infect other hosts because it has not yet been loaded into memory and the active phase, in which resident virus resides in memory and infects any suitable program that is executed on the computer. Two computer compartments with different infection rate are established. Furthermore, the dynamic behaviors of this model are investigated by stability theory and numerical simulations. It is found that the dynamical properties of this model are determined by basic reproductive rate. Specifically, virus-free equilibrium is globally asymptotically stable if basic reproductive rate is less than or equal to one , whereas the local asymptotical stability of the viral equilibrium is guaranteed if basic reproductive rate is bigger than one, followed by a conjecture on its global stability. Then the sensitivity analysis of basic reproductive rate to the system parameters is investigated and a collection of policies is advised to control the spread of computer virus over the Internet.     

Study on global optimization control strategy of ISG velocity coupling hybrid electric vehicle

Hybrid system has the advantage of energy conservation and environmental protection. To improve the fuel economy of a hybrid system,based on the structure of the ISG velocity coupling HEV(hybrid electric vehicle),a dynamics simulation model is built. By using dynamic programming(DP) global optimization method,the variables of the engine throttle and the motor torque are set as the control variables,and the engine speed and the battery SOC are set as the state variables,the engine fuel economy is set as the objective function,and the battery SOC balance and the limited frequent shifting are set as the additional cost function. Then a global optimization program is built,and the simulation results indicate that the fuel economy of DP control HEV is 35.5% more efficient than that of the conventional vehicle.     

树高精准化测量原理与模型及其精度研究

树高的精准测量是森林资源经营和管理的一项基础工作,也是评价立地质量和林木生长状况的重要依据。实验中利用测高器、罗盘仪、经纬仪和全站仪等仪器测定了7个不同树种的树高,阐述了其测量的原理与过程,并构建了树高精准化测量的模型。根据30组不同树种的树高测量数据进行对比和分析,得出树高自动精准测量的结果：全站仪的精度最高,其次是经纬仪和罗盘仪,最后是测高器。采用相同的仪器测量不同树种的树高,其精度也不同。树干笔直、树冠简单的树种精度较高;针叶树种也比阔叶树种精度高。构建的树高测量模型,为实现林业调查的自动化和精准化提供了理论依据。     

北方稻区国家水稻品种区域试验精确度分析

以1999—2008年北方稻区国家水稻品种区域试验(共计463个点次) 10年数据为依据,在一年一点和一年多点两个层次上对北方稻区国家水稻品种区域试验的精确度进行了研究。结果表明: (1)一年一点试验层面上,所有试点平均试验误差变异系数(CV)为4.3%,平均相对最小显著差数(RLSD)为7.4%,绝大多数试点的CV和RLSD控制得较好,试验精确度和品种比较精确度均较高。(2)一年多点试验层面上,绝大多数组别的CV在5%以内,RLSD在3%以内,试验精确度较高,品种比较精确度能够满足国家品种审定的要求。(3)在现有试验方案下,降低试验误差是提高一年一点试验精确度的主要途径;除降低试验误差外,适当增加试点数是提高一年多点试验精确度的有效选择。     

Algorithm Discussion of High Precision for Wireless User Location

In recent years , because of increasing mobile users ,the wireless location and business is the most attractive business in the world , accurate location information to users has become one of criterion business for mobile communication ,so a discussed deeply wireless location technology is very value. This paper discusses it from high accuracy algorithm for wireless location on the network , by the emulation and comparison, it has shown that there are different algorithms in different surroundings for arriving at satisfied precision     

Technology of the Rapid Prototyping Manufacturing Precision of Thin-shell Part

To the photo-solidification rapid prototyping technology, the precision of parts relate directly to their size and structural characteristics, not to their complexity. However, variant prototyping processes bring about variant surface shapes and dimension precisions. The authors compare its prototyping precision and prototyping time by testing a thin-shell exterior trimming part at variant laying angles and under variant bracing conditions. And then reduced model is founded, warping deformation of variant bracing diaphragms and sheet metals at optima laying angle are surveyed, finally the process to upraise the rapid prototyping precision of the thin shell parts is set up. Experiments are then done to test the process.     

虚拟植物的发展概况与应用

近三十年来,随着计算机技术的发展,虚拟植物的研究取得了显著进步,已经成为精准农业的一项核心技术,并在多个领域中得到了广泛的应用。本文概述了虚拟植物的发展历史和近年来的研究现状,并根据现有的技术缺陷分析了虚拟植物未来的发展方向,最后介绍了虚拟植物在科学实验、精准农业、教育培训和动漫影视中的实际应用。     

黑龙江省水稻种质资源农艺性状鉴定与筛选

依据《水稻种质资源描述规范和数据标准》调查标准,对黑龙江省水稻地方品种123份、国外引进品种68份和黑龙江省选育品种82份进行农艺性状精准鉴定,对273份不同类型水稻农艺性状指标进行等级分类,筛选综合性状优异材料为地方品种共7份、国外品种13份、选育品种13份,其将对黑龙江省水稻育种事业发展起到积极的促进作用。     

在线红外水分仪测量系统分析

为评价制丝在线红外水分仪的测量精度,以烘丝机出口水分仪为例,分析烘箱的稳定性及水分仪的线性和偏倚,作出其测量能力能否满足测量要求的评价,为卷烟生产线测量设备的精确度分析提供一种评价参考方法。