参数化鲁棒极点配置方法

研究了一类线性多变量系统鲁棒控制器的设计问题，提出了一种基于极点配置和目标函数优化的鲁棒极点配置方法。解决问题的基本思想是，利用极点配置的参数化表示结果，以系统输出的Ｌ∝范数作为极点配置的鲁棒性准则，给出鲁棒极点配置的优化命题。通过解这一优化命题确定极点配置问题中的自由参数，从而达到设计鲁棒控制器的目的。     

鲁棒极点配置的优化算法

本文研究了一类线性多变量系统的鲁棒极点配置问题，提出了一种基于目标函数优化的鲁棒极点配置算法，解决问题的基本思想是，利用极点配置的参数化表示结果，以系统输出的Ｌ∞范数作为极点配置寻优的准则函数，在这个准则下，通过解优化问题的途径确定极点配置问题中的自由参数，从而达到鲁棒极点配置的目的。     

广义系统极点配置的一种代数几何方法

利用代数几何方法给出了可任意配置极点的条件,并证明了实数域上广义系统若存在复 反馈配置极点,则一定存在实反馈配置极点.     

线性系统极点配置问题的算法及实现

线性系统的动态性能主要取决于系统极点的位置。极点配置问题就是把闭环极点组配置到所希望的位置上 ,等价于使综合得到的系统动态性能达到期望的要求。极点配置问题的算法有多种 ,特别是对于多输入系统 ,其计算较为复杂。该文提出了一个基于Luenberger能控规范型的极点配置问题的算法和步骤 ,并就此问题给出了一个具有实用价值的MATLAB通用程序     

圆形区域内鲁棒极点配置优化

本文基于和声搜索算法将精确极点配置的思想推广到圆形区域极点配置,通过对圆域内极点全局优化的方法,实现圆域内鲁棒极点配置问题.首先,基于几何原理描述极点在圆形区域内的位置信息,确定了在圆形区域内动态选择极点的规则,可以保证算法在圆形区域内动态选取极点.然后,对圆形区域内的极点,基于精确鲁棒极点配置的思想,利用和声搜索算法优化摄动或不确定性的谱范数上界,从而得到一组允许闭环系统具有更大摄动或不确定性的极点及相应的状态反馈控制器.最后,通过实例进行仿真,仿真结果表明本文采用和声搜索算法全局优化动态选择极点方法得到的闭环系统具有更好的鲁棒性.     

广义系统极点配置的一种代数几何方法

利用代数几何方法给出了可任意配置极点的条件，并证明了实数域上广义系统若存在复反馈配置极点，则一定存在实反馈配置极点．     

关于状态反馈预测控制系统的极点配置

讨论按极点配置方法的设计问题,给出极点可任意配置的充分必要条件。基于状态空间模型,给出按极点配置方法设计时选取预测时域的方法。通过引入控制作用衰减系数及状态反馈加权系数,状态反馈预测控制系统的极点可任意配置。设计参数实时在线调整方便,增强了预测模型的适应范围,使预测控制系统具有较好的的控制性能和鲁棒性。     

一类分布参数控制系统极点配置的构造

在Hilbcrt空间中,考虑D. P. S.的极点配置问题。以往的工作,例如[2],假设A仅有单特征值。本文给出A有重特征值时的极点配置定理并推导出极点的配置公式。     

部分扇形区域极点配置的可靠控制

针对线性定常系统,采用连续增益故障模型提出了考虑执行器故障的部分扇形区域极点配置的可靠控制问题.当系统发生故障时,正常控制的闭环系统极点可能跳出所给定的复平面区域,而可靠控制的闭环系统仍然保持极点在指定的区域内。本文利用线性矩阵不等式(LMI)给出了部分扇形区域极点配置的可靠控制器存在的充分条件。研究成果的仿真,不仅验证所提出方法的可行性;而且比较了部分扇形区域极点配置正常控制器和可靠控制器的控制效果。进一步看出对系统进行可靠极点配置的必要性。     

极点配置问题线性可解的充要条件

本文研究线性系统在输出反馈作用下的极点配置问题,得到了系统可由"线性化"方法任 意配置n个(等于系统的维数)闭环极点的充要条件.并给出了一种新的极点配置方法.     

Computer experience, learning style, and hypermedia navigation

This study focused on the extent to which prior computer-related experiences predicted linear and nonlinear navigation when using a hypermedia learning environment. Those with more years’ experience at working with computers and those with more authoring experience took more linear steps, whereas those with more data base experience and those with more hypermedia experience took fewer linear steps. Those with more years experience at working with computers, those with more programming experience, and those with more authoring experience had a lower percentage of nonlinear steps than those with more experience in those three areas. Those with more word-processing experience, more spreadsheet experience, and more hypermedia experience had a higher percentage of nonlinear steps than those with less experience in those three areas. Also, those with more hypermedia experience took less time than those with less hypermedia experience. A major implication of the study is that we can predict the extent to which a hypermedia user may engage in a hypermedia environment in a nonlinear way by knowing his or her experience in a variety of computer-related uses.     

基于AOP技术的Composite模式的改进

Composite模式是解决部分与整体关系时常用的设计模式,但基于面向对象设计(OOP)所实现的Composite模式中存在的问题很难利用OOP解决。该文应用面向方面编程(AOP)改变类的行为,利用AspectJ实现Composite模式,通过与以OOP技术实现的Composite模式比较,得出应用AOP方法能够较好地实现责任分离,具有较高的可扩展性,模块结构更清晰。     

多传感器时滞系统信息融合最优Kalman滤波器

基于线性最小方差最优加权融合估计算法,对多传感器的离散线性状态时滞随机系统,给出了一种非增广分布式加权融合最优Kalman滤波器.推导了状态时滞系统任两个传感器子系统之间的滤波误差互协方差阵的计算公式.它与状态增广加权融合滤波器具有相同的精度.与每个传感器的局部滤波器相比,分布式融合滤波器具有更高的精度.与状态和观测增广最优滤波器相比,具有较小的精度.但避免了增广所带来的高维计算和大的空间存储,可减小计算负担.仿真例子验证了其有效性.     

Multibody systems with 3D revolute joints with clearances: an industrial case study with an experimental validation

This article is devoted to the analysis of the influence of the joint clearances in a mechanism of a circuit breaker, which is a 42 degree-of-freedom mechanism made of seven links, seven revolute joints, and four unilateral contacts with friction. Spatial (3D) revolute joints are modeled with both radial and axial clearances taking into account contact with flanges. Unilateral contact, Coulomb’s friction and Newton impact laws are modeled within the framework of nonsmooth mechanics without resorting to some regularizations or compliance/damping at contact. The nonsmooth contact dynamics method based on an event-capturing time-stepping scheme with a second order cone complementarity solver is used to perform the numerical integration. Furthermore, the stabilization of the constraints at the position level is made thanks to the stabilized combined projected Moreau–Jean scheme. The nonsmooth modeling approach together with an event–capturing time-stepping scheme allows us to simulate, in an efficient and robust way, the contact and impacts phenomena that occur in joints with clearances. In particular, comparing with the event-detecting time-stepping schemes, the event-capturing scheme enables us to perform the time-integration with a large number of events (impacts, sliding/sticking transitions, changes in the direction of sliding) and possibly with finite-time accumulations with a reasonable time-step length. Comparing with compliant contact models, we avoid stiff problems related with high stiffnesses at contact which generate some issues in contact stabilization and spurious oscillations during persistent contact periods. In the studied mechanisms of the circuit breakers, the numerical method deals with more than 70 contact points without any problems. Furthermore, the number of contact parameters is small—one coefficient of restitution and one coefficient of friction. Though they are sometimes difficult to measure accurately, the sensitivity of the simulation result with respect to contact parameters is low in the mechanism of the circuit breaker. It is demonstrated that this method, thanks to its robustness and efficiency, allows us to perform a sensitivity analysis using a Monte Carlo method. The numerical results are also validated by careful comparisons with experimental data, showing a very good correlation.     

Effects of child restraint system features on installation errors

This study examined how child restraint system (CRS) features contribute to CRS installation errors. Sixteen convertible CRS, selected to include a wide range of features, were used in volunteer testing with 32 subjects. Subjects were recruited based on their education level (high or low) and experience with installing CRS (none or experienced). Each subject was asked to perform four child restraint installations in the right-rear passenger seat of a 2006 Pontiac G6 sedan using a crash dummy as a child surrogate. Each subject installed two CRS forward-facing (FF), one with LATCH and one with the vehicle seatbelt, and two CRS rear-facing (RF), one with LATCH and one with the seatbelt. After each installation, the experimenter evaluated 42 factors for each installation, such as choice of belt routing path, tightness of installation, and harness snugness.Analyses used linear mixed models to identify CRS installation outcomes associated with CRS features. LATCH connector type, LATCH strap adjustor type, and the presence of belt lockoffs were associated with the tightness of the CRS installation. The type of harness shoulder height adjuster was associated with the rate of achieving a snug harness. Correct tether use was associated with the tether storage method. In general, subject assessments of the ease-of-use of CRS features were not highly correlated with the quality of their installation, suggesting a need for feedback with incorrect installations.The data from this study provide quantitative assessments of some CRS features that were associated with reductions in CRS installation errors. These results provide child restraint designers with design guidelines for developing easier-to-use products. Research on providing effective feedback during the child restraint installation process is recommended.     

Organization of Parallel Query Processing in Multiprocessor Database Machines with Hierarchical Architecture

The development of database systems with hierarchical hardware architecture is currently a perspective trend in the field of parallel database machines. Hierarchical architectures have been suggested with the aim to combine advantages of shared-nothing architectures and architectures with shared memory and disks. A commonly accepted way of construction of hierarchical systems is to combine shared-memory (shared-everything) clusters in a unique system without shared resources. However, such architectures cannot ensure data accessibility under hardware failures on the processor cluster level, which limits their use in systems with high fault-tolerance requirements. In this paper, an alternative approach to construction of hierarchical systems is suggested. In accordance with this approach, the systems is constructed as an assembly of processor clusters with shared disks, with each cluster being a two-level multiprocessor structure with a standard strongly connected topology of interprocessor connections. A stream model for organization of parallel query processing in systems with the hierarchical architecture suggested is described. This model has been implemented in a prototype parallel database management system Omega designed for Russian multiprocessor computational systems MBC-100/1000. Our experiments show that the total performance of the processor clusters in the Omega system is comparable with that of the processor clusters with shared resources even in the case of great data skew. At the same time, the clusters of the Omega system are capable of ensuring a higher degree of data availability compared to the clusters with shared-memory architectures.     

基于FPGA的图像预处理快速算法及仿真

工程实践中,可编程逻辑器件已经越来越多的受到重视和应用.文中以DSP处理大量数据时,实时性难以达到要求入手,介绍了应用可编程逻辑器件FPGA提高程序效率、实现快速运算的一种方法,并设计了一个利用中值滤波进行图像预处理的系统,之后进行了仿真和实验验证.文章最后得到结论,采用FPGA通过用硬件逻辑来实现运算量大但相对比较简单的算法,效率要大大高于软件的多次循环,若在系统中采用DSP和FPGA合作处理数据,则可以各自发挥长处,实现快速算法.     

面向计算机的产品创新设计新模型与新原理(II)

该文基于物元动态系统理论提出了产品虚实模型、产品潜显模型、产品正负模型等产品创新设计模型,分析了产品的同素多构性、一关系多实体性、同构多素性、虚实统一性、一显多潜性、一正多负性等性质。给出在一定的条件下,异构同功,异素同功、同潜产品同功,以及同正产品可互相转化产品、同负产品可互相转化的产品创新设计新原理。新模型和新原理有利于开发计算机辅助产品创新设计系统CAPCDS。     

Control 5.0: From Newton to Merton in Popper's Cyber-Social-Physical Spaces

The future of control in cyberspace of parallel worlds is discussed. It argues for the coming age of Control 5.0, the control technology for the new IT capable of dealing with artificial worlds with VR, AR, AI and robotics. The discipline of automation needs a new interpretation of its core knowledge and skill set of modeling, analysis, and control for cyber-socialphysical systems, and a paradigm shift from Newtonian Systems with Newton's Laws or Big Laws with Small Data to Mertonian Systems with Merton's Laws or Small Laws with Big Data.      

具有控制时滞系统的最优无静差正弦扰动抑制

研究在外部正弦扰动作用下,控制含时滞的线性系统的最优无静差调节器设计问题．首先利用Artstein变换将控制变量含时滞的系统转化为不舍时滞的系统;然后利用内模原理构造扰动补偿器,将带扰动的系统转化为无扰动的增广系统,从而将无静差扰动抑制问题转化为无扰动增广系统的最优调节器设计问题;最后利用最优控制理论求得最优无静差反馈控制律．仿真结果表明了所提出方法的有效性．