激光跟踪仪精密伺服系统建模及仿真研究

设计高性能的精密伺服系统,为激光跟踪仪实现跟踪和精密测量,针对精密伺服系统转速低、响应快、精度高的性能要求,提出一种永磁同步电机(PMSM)矢量控制原理及空间矢量脉宽调制(SVPWM)算法的精密伺服系统建模的方法,在Matlab/Simulink环境中搭建了位置、速度和电流三闭环控制系统仿真模型.仿真结果验证了上述系统模型的有效性,通过使用变速积分PI算法进行PI调节器设计对仿真模型进行优化,最终实现精密伺服系统在低转速范围内,能够快响应、高精度平稳运行.结果证明,提出的建模方法为实际控制系统设计、调试和运行提供了充分的理论依据.     

基于Simscape的车辆ABS建模与仿真研究

关于车辆ABS系统建模优化问题,传统的建模方法缺少具体的车辆组件模型和完善的物理系统模型,且纯数学理论模型较晦涩和理想化.为解决上述问题,提出一种基于Simscape的物理系统建模方法,可以支持不同类型物理系统的复杂过程的混合建模和仿真,比传统模型更具物理性和更切合实际情况,且构建的车辆组件模型具有独立性和通用性.为验证物理系统模型的正确性和真实性,针对干沥青、湿泥土和积雪三种路面条件的刹车过程进行了仿真研究.仿真结果表明,利用Simscape搭建的物理模型是真实可靠的,更有利于对ABS系统高效快捷地开展相关的动力学分析.     

液压驱动伺服机器人的模糊滑模控制研究

针对液压驱动四足机器人伺服系统非线性和不确定性严重的问题,提出了一种快速响应、鲁棒性好、控制精度高的模糊滑模控制器,并进行了仿真研究.首先,建立了液压驱动伺服机器人的液压动力机构非线性数学模型,利用Lyapunov方法设计了滑模控制器;其次,构造了一个模糊边界层宽度调节器,削弱滑模控制的抖振;最后,分析了参考力、液压参数、供油压力及负载刚度变化对系统输出的影响.仿真结果表明,该控制器对液压伺服力系统非线性和参数变化具有较好的控制效果.该方法用于四足液压驱动伺服机器人的控制是可行的、有效的.     

永磁直线伺服系统二自由度H∞控制器设计

对永磁直线伺服系统速度提出基于模型匹配的二自由度H∞动态控制器设计。将二自由度控制与H∞控制相结合,在建立模型匹配二自由度H∞控制系统状态空间模型的基础上,将直线伺服系统的速度动态控制器设计问题归结为标准的H∞控制问题,通过求两个Ricati方程的解得到H∞控制器,以保证永磁直线伺服系统的鲁棒性。仿真实验结果表明,用该方法设计的永磁直线伺服系统具有良好的抑制扰动和跟踪给定的效果,满足数控机床及机器人等高精度系统对直线伺服速度控制的要求。     

基于Mechanism/Pro的汽车悬架系统运动仿真

为了解决多体动力学分析仿真过程中困扰仿真人员的模型建立和修改问题,以汽车独立悬架为研究对象,提出机械系统仿真一种比较理想的方法.首先应用多体动力学求解理论,从悬架物理模型中提取多体动力学求解模型.针对ADAMS/View建模能力较弱,通过三维建模软件Pro/E建模,采用Mechanism/Pro模块定义刚体、添加约束和驱动、调用ADAMS/Solver求解.可以很方便地建立复杂机械系统模型,并根据仿真结果及时对模型进行修改,实现机械系统多体动力学仿真的前处理、求解以及后处理均集成在Pro/E环境中.     

基于自适应模糊PID控制的太阳光跟踪伺服系统

针对太阳光跟踪伺服系统中传统PID控制过程中的一些问题,通过对自适应模糊PID控制系统的分析,设计了一种双轴跟踪伺服系统自适应模糊PID控制器,同时在Simulink环境中建立了方位角跟踪传动机构仿真模型并完成了仿真。仿真结果表明,太阳光跟踪伺服系统自适应模糊PID控制器较传统PID控制器具有较强的稳定性、适应性与鲁棒性,在太阳光跟踪伺服系统控制领域具有重要的实用价值与应用空间。     

变结构并联多维振动台自由度特性与运动学分析

基于3-P(4S)构型设计并研制了一种直线电机驱动的、平衡位姿可调的变结构并联多维振动台.运用约束螺旋理论分别对子闭环初始安装为平行四边形和梯形的两种构型进行自由度特性分析.建立两种构型的运动学位姿模型,研究机构位姿输出与驱动输入的关系,通过迭代搜索法求解梯形安装时机构的非线性约束方程组.根据位姿分析,分别用反解搜索法和正解遍寻法得到两种初始安装条件下机构的可达工作空间以及梯形安装时的伴随转角空间.通过数值算例验证理论分析结果,对机构进行运动仿真,研究不同装配结构下振动台机构的运动输出特性.依据理论分析与仿真结果进行实物样机运动实验,将理论计算、仿真分析和实验的结果进行对比,进一步验证了理论分析的正确性以及样机工程应用的可行性.     

玉米叶片物理建模与参数确定的运动学分析方法

基于物理的方法是解决植物动态建模与仿真的有效途径,而模型参数的确定是基于物理方法所面临的重要问题.为实现基于生物物理属性特征的玉米叶片高精度、高真实感动态建模与仿真,提出一种基于运动学分析的玉米叶片物理建模与参数确定方法.首先利用运动捕捉技术获取玉米叶片的运动数据;然后根据运动捕捉特征点构建基于质点-弹簧系统的物理模型;最后基于运动学分析建立物理模型参数解析方程组,利用最小二乘法计算物理模型的参数.以此参数构建物理模型实现玉米叶片的动态模拟,并给出2种模型构造方式的玉米叶片虚拟仿真.结果表明,该方法以一种数据驱动的机制有效估算出对应的物理模型参数,生成的玉米叶片动态虚拟仿真过程具有与实际情况较为接近的真实感效果,为虚拟植物建模与应用提供了一种可行的物理建模及参数确定方法.     

基于模型的飞机电滑行系统设计与研究

详细介绍了基于模型的飞机电滑行系统的开发流程与方法,并对其进行了集成仿真分析。利用Matlab/Simulink建立了电滑行系统需求的行为模型,利用Simscape建立了电机物理模型,根据电滑行系统架构进行多专业的联合仿真,验证系统的功能、性能和接口信息等。通过模型的方式实现了对系统设计的分析和确认,实现系统的图形化设计与传递,以及系统需求、系统架构、仿真模型的可追踪与追溯性,在系统开发早期验证设计,能发现潜在问题,从而避免设计的迭代。应用集成仿真验证了模型在电滑行系统设计中的指导作用。     

高功率因数PWM整流器PI调节器的仿真研究

对单相PWM整流器进行了分析,推导出了相应的数学模型和控制结构框图.针对单相PWM整流器建模难和电流、电压控制环的PI调节器设计难的问题,提出了一种基于古典线性控制对非线性进行线性化和输入输出能量守恒相结合的单相PWM整流器的PI调节器的设计方法.分别对电流、电压控制环的调节器进行了选型和参数设计.采用基于Matlab/SimPower Systems的方法对整个控制系统进行建模和仿真验证.仿真结果得出双闭环PI调节器均能很好的满足控制系统的稳定性和动态性要求.因此,文中提出的单相PWM整流器PI调节器的设计方法在工业控制中有推广应用的广阔前景.     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate