电动缸测控系统的仿真与通信

为了研究电动缸的性能和控制系统,利用虚拟仪器LabWindows/CVI设计了电动缸测控系统的仿真软件.通过对电动缸数学建模,并模拟电动缸伺服驱动器的位置信号,采用增量式PID、步进式PID及专家PID控制算法对控制效果进行仿真.为了使控制效果达到最佳,采用遗传算法对PID参数进行整定,结合Matlab/GUI实现在线参数整定,并通过Polling Queue技术实现数据的通信.仿真结果表明,该仿真软件达到了较好的控制效果.     

模糊控制在摆缸位置伺服系统中的应用

由于摆动气缸的摩擦转矩、空气可压缩性、比例阀的压力特性等非线性因素的存在,要得到摆缸伺服系统精确的数学模型十分困难,而且气动系统易受周围环境因素的影响,当采用传统PID控制时,很难使系统长时间保持良好的控制效果,尤其是当有一定的外界干扰之后会导致系统工作不稳定.利用Matlab实时仿真模块的功能,把模糊自适应整定PID的控制算法引入到伺服系统的控制器设计中,搭建的半实物仿真模型,对系统进行半实物仿真实验,并通过不断地在线修改控制规则,提高控制器的控制性能,实验结果表明,模糊PID控制效果良好.     

电动负载模拟器多余力矩抑制方法研究

为了解决多余力矩对电动负载模拟器强干扰,影响加载指令跟踪精度的问题,论文将基于蚁群优化的PID控制方法用于加载电机控制器的设计。首先在分析加载电机结构以及工作原理的基础上建立了电动加载系统的数学模型,并利用结构不变性原理进行前馈补偿推导;其次针对常规PID控制器无法通过变参数来应对复杂的非线性环境的问题,提出了一种基于蚁群算法优化PID控制器参数的复合控制策略;最后通过仿真验证了该控制策略在对多余力矩消除上要优于常规的PID控制。     

数控系统中伺服系统位置前馈控制器的设计

针对数控机床运行过程中存在的位置定位精度控制问题,提出了一种基于速度和加速度前馈控制的位置控制器,并采用三角函数加减速控制算法,通过前馈控制器可以使伺服系统获得快速的动态响应,并且通过对位置环比例积分系数的调节,可以保证系统定位的高精度、无超调。采用Simulink工具软件建立了位置精度控制的仿真模型,得出了相应的仿真结果。验证了本文所设计的位置前馈控制器的工程实用性。     

自适应模糊PID前馈补偿在机载挂飞摆扫转台控制中的应用

针对机载挂飞转台的摆扫速度控制问题,提出了一种利用模糊自适应PID技术进行前馈补偿的复合控制策略。首先根据实际应用提出摆扫转台的期望摆扫速度曲线,并对直流力矩电机驱动的摆扫转台进行了建模;然后根据扰动前馈补偿的控制原理,提出了模糊自适应PID前馈补偿方法,为摆扫转台的速度环设计了模糊PID控制器,并在此基础上设计了与之相适应的的自适应前馈补偿函数;最后进行了仿真结果验证。通过Matlab仿真结果表明,相对于模糊PID控制,所设计的模糊自适应PID前馈补偿控制器能有效的跟踪期望的转台摆扫速度,大幅地提高了在有稳定干扰和摆扫速度越变情况下的跟踪精度。     

液压驱动型四足机器人电液伺服控制系统仿真建模与实验分析

复杂的作业环境和艰巨的作业任务使液压驱动型四足机器人对其伺服系统的精度、速度和力量均比一般机器人在普通情况下有更高的要求。为掌握液压驱动型四足机器人在多种路况下行走时各液压缸的受力情况以及液压系统内流量、压力的变化情况,需要对其虚拟样机进行机械动力系统和液压伺服系统的联合仿真,定性分析电液伺服系统位置、速度等被控对象的特性,并分析PID控制器在四足机器人伺服控制方面的特性与不足。针对传统控制算法在四足机器人控制存在的短板问题,设计了一种非对称前馈补偿模糊自适应PID算法,并利用物理样机进行了实际验证。实验结果为四足机器人电液伺服控制系统硬件、软件和控制算法的设计与优化指明了方向,还为研究四足机器人平稳步态控制策略提供了决策依据和数据支持。     

基于Lbest PSO和NNs的电液伺服系统输出力PID控制研究

为了实现电液伺服系统输出力的稳定控制,结合局部最优粒子群优化算法和神经网络模型,提出一种PID控制器设计方法。该方法将神经网络模型(NNS)与PID控制器耦合,得到基于神经网络的PID控制器参数整定结构;再采用局部最优粒子群优化算法(Lbest PSO)确定神经网络的权重,从而得到基于局部最优粒子群优化算法和神经网络的PID控制算法;最后将提出的PID控制算法用于控制虚拟的电液伺服加载系统,以进行仿真实验。仿真结果表明,由该PID控制器控制的电液伺服系统的输出力平稳地收敛于给定力,从而提高了系统的稳定性。     

一种非线性PID控制算法的仿真研究

研究PID控制系统优化问题,工业控制被控对象均具有非线性、时变和大时滞性,引起系统的品质性能差,传统的线性控制难以达到所要求精度。为了提高系统控制精度,利用PID控制器各增益参数与偏差信号间的非线性关系,提出一种非线性PID控制算法。首先将PID参数转化为优化问题,然后采用粒子群算法的全局、并行搜索能力对非线性控制参数进行求解,得到一组最优的PID控制参数。仿真结果表明,相对于传统线性PID控制,非线性PID控制器超调小,调节时间短,并提高了控制精度,有效解决了传统PID难以准确控制非线性对象的难题。     

非线性优化控制算法在合成氨生产中的应用

针对合成氨生产过程控制仿真中被控参数的非线性、时变性和不确定性等特征引起的控制系统执行效率差,线性控制优化精度低等问题,提出了一种粒子群优化的非线性控制算法.首先将PID控制器控制增益与信号偏差的非线性关系进行修正,将其控制参数动态调节转化为粒子群优化问题;然后利用粒子群优化算法在控制参数的三维空间内进行非线性参数最优解搜索,得到PID控制器的最优控制参数;最后利用该非线性控制算法对合成氨生产过程控制进行仿真测试.测试表明,优化控制算法相对于传统的PID控制,具有较优的系统稳态,且阶跃响应振幅低,系统稳定性高.     

风力发电机组的变桨距复合控制

针对变桨距风力发电机组的强非线性和时滞特性,受参数变化和外部干扰严重,提出了基于前馈补偿和模糊PID的复合控制策略来实现变桨距功率控制.将模糊控制与常规的PID控制相结合,设计了模糊自整定PID控制器对控制参数进行在线调整.考虑风速是一个可测的主要扰动,设计了前馈补偿器,采用分段比例控制补偿一个适当的前馈桨距角,在额定风速以上时作用于系统,实现按扰动的快速补偿.变桨距控制系统采用S7-1200PLC作控制器,编写程序实现了变桨距复合控制.试验表明,系统抗扰能力强,控制效果良好.     

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.     

Call for Papers The 6^th International Conference on Grid and Cooperative Computing

Recent years have seen rapid advances in various grid-related technologies, middleware, and applications. The GCC conference has become one of the largest scientific events worldwide in grid and cooperative computing. The 6th international conference on grid and cooperative computing (GCC2007) Sponsored by China Computer Federation (CCF),Institute of Computing Technology, Chinese Academy of Sciences (ICT) and Xinjiang University ,and in Cooperation with IEEE Computer Soceity ,is to be held from August 16 to 18, 2007 in Urumchi, Xinjiang, China.     

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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