Performance-oriented parallel distributed compensation

The main idea of the original parallel distributed compensation (PDC) method is to partition the dynamics of a nonlinear system into a number of linear subsystems, design a number of state feedback gains for each linear subsystem, and finally generate the overall state feedback gain by fuzzy blending of such gains. A new modification to the original PDC method is proposed here, so that, besides the stability issue, the closed-loop performance of the system can be considered at the design stage. For this purpose, the state feedback gains are not considered constant through the linearized subsystems, rather, based on some prescribed performance criteria, several feedback gains are associated to every subsystem, and the final gain for every subsystem is obtained by fuzzy blending of such gains. The advantage is that, for example, a faster response can be obtained, for a given bound on the control input. Asymptotic stability of the closed loop system is also guaranteed by using the Lyapunov method. To illustrate the effectiveness of the new method, control of a flexible joint robot (FJR) is investigated and superiority of the designed controller over other existing methods is demonstrated.     

公司政治关联国外研究新进展

公司政治关联问题引起了战略管理学者的广泛关注,正成为一个前景广阔的热点研究领域.本文系统回顾了最近几年本领域国外研究的新进展,突出了针对转型经济体公司政治关联研究的新贡献.本文试图梳理如下问题:公司政治关联会产生哪些效应;在什么条件下存在政治关联;其作用的发挥受到哪些因素调节;以何种方式进行而发挥作用.在总结目前研究局限的基础上,提出了未来四个主要研究方向.     

科研项目负责人胜任特征与领导有效性的关系:变革型领导的中介作用

基于文献分析,提出了以变革型领导为中介变量的科研项目负责人胜任特征与领导有效性之间的中介作用假设模型.采用问卷调查法及因素分析技术对281名优秀科研项目负责人的数据进行分析,得出科研项目负责人胜任特征模型具有三个维度,即领导性胜任特征、研究性胜任特征和管理性胜任特征;而后采用多元分层回归与路径分析技术研究了三者之间的关...     

封面设计中基本构图要素的传统美学观照

基本构图要素是与符号不同且更为基本的封面视觉传达要素,对于读者的封面阅读审美过程具有重要作用。封面阅读的审美过程与读者的文化传统有着深厚的关联,创作者在进行封面设计时必须考虑中国读者的独特审美倾向:欣赏"平衡"之美,追求"中和"之美,偏爱"飞动"之美,崇尚"清新"之美。     

班主任生活中的几个案例及解决方法

班主任工作是个复杂的工作,千头万绪,但是要想成为一个优秀的班主任最起码的一条就是要了解学生。本文笔者通过自己亲身经历的四个案例来剖析如何做到了解学生。     

浅谈“教书育人”的体会

笔者通过多年来的班主任工作,总结出＂教书育人,为人师表＂这一任务是艰巨而光荣的,主要依靠提高本身修养、师生相互理解、运用＂严、实、细、亲＂取得良好的效果。     

大学与中学德育衔接存在的问题及解决对策

近些年大学与中学德育衔接工作取得了一定的成绩,但还存在对德育衔接重视不够、德育目标定位不准、德育内容体系不健全、教育合力不高等问题。为此,要深化教育体制改革,树立德育衔接意识,督促各层次学校重视德育工作,树立大德育观等,以加强大学与中学德育的衔接,提高德育的实效。     

Optimum calibration of a parallel kinematic manipulator using digital indicators

This paper presents a calibration method for parallel manipulators using a measurement system specially installed on an external fixed frame. The external fixed frame is important as an error reference for calibration in certain operations, such as in the configuration of a parallel manip- ulator functioning as a machine tool where the workpiece is fixed to a worktable. The pose of the end-effector is mea- sured using three digital indicators installed on the external fixed frame. To enable measurement, the end-effector is assumed to be a plane large enough that all digital indicators could touch. The error is defined as the difference between the theoretical and actual readings of the digital indicators. The geometric parameters of the parallel manipulator are optimized to minimize this error. This calibration method is low cost and feasible for compensating geometric parameter errors for a parallel manipulator. Optimal pose selection for the calibration is achieved using a swarm intelligence search algorithm. The method is implemented on a prototype of a six degrees-of-freedom （DOFs） Gough-Stewart platform constructed to function as a machine tool.     

水系锂离子电池体系及电极材料的研究进展

与传统锂离子电池相比,水系锂离子电池具有安全性好、电导率高、装配简易和成本低等优点。本文综述了近年来在该领域研究的电池体系,并从正负极材料、电解液及衰减机理等方面介绍了水系锂离子电池的研究进展,对目前存在的主要问题及发展前景进行了分析展望。     

“关系”一词及其翻译

“关系”一词被普遍认为是具有中国特色的词汇,负载丰富的文化内涵。但在其汉译英过程中,却有多个不同的翻译版本。该文将对“关系”一词进行研究,并对其主要的几个英文翻译版本进行讨论,最终得出结论：诸如“关系”这样具有文化特色的词汇,如在译入语中不能找到相应对等的词汇表达,最好的翻译方法还是音译。