基于线性自抗扰的烷氧基化装置温度控制系统

烷氧基化装置温度控制系统具有大时滞特性,温度高效控制困难.建立系统数学模型;提出内环为PD控制器,外环为Smith预估器与线性自抗扰控制相结合的控制策略,以解决时滞系统采用自抗扰控制时扩张状态观测器输入信号不同步及Smith预估器抗扰能力差的问题;设计线性自抗扰控制器;从不同点加入扰动进行数值仿真实验,仿真结果证明了所提出方法的有效性.     

基于反双曲正弦函数的自抗扰控制器

利用反双曲正弦函数分别设计了三阶跟踪微分器和三阶扩张状态观测器,并利用该函数和设定输入的二阶微分信号设计控制律,从而构造了一种新型自抗扰控制器.通过李雅普诺夫函数证明了自抗扰控制系统在平衡点处渐近稳定.仿真实验表明,采用该自抗扰控制器的二阶系统能有效抑制内部和外部非线性扰动的影响,实现对方波信号和正弦信号的高精度跟踪,同时,扩张状态观测器能较准确地估计系统内部和外部扰动信号.     

非线性自抗扰状态PI控制器的研究

针对线性状态PI控制器只适用于单输入单输出的线性系统的不足 ,提出了非线性自抗扰状态PI控制方法 ,将“自抗扰”控制技术的控制思想应用于常规状态PI控制 ,使其适用于单输入单输出的非线性系统的控制。解决了“自抗扰”控制技术中扩张状态观测器的参数问题 ,并对系统的稳定性进行了定性分析。仿真算例表明 ,非线性自抗扰状态PI控制器对对象模型参数摄动和外扰具有良好的适应性和鲁棒性     

变论域自适应模糊分数阶自抗扰控制器设计

提出了一种变论域自适应模糊分数阶自抗扰控制算法,用以提高分数阶系统的性能;在变论域自适应模糊控制的设计中,引入分数阶扩张状态观测器和分数阶跟踪微分器;在变论域自适应模糊分数阶自抗扰控制中,利用分数阶跟踪微分器将输入信号转化为平滑跟踪和高质量差分信号,用扩张状态观测器获取每个状态变量的估计值、不确定性的实时动态模型以及外部扰动．为了消除稳态误差,提高控制精度,提出了可变值域的扩张状态误差积分;将变论域自适应模糊分数阶自抗扰控制算法和分数阶自抗扰控制 (FADRC)算法对典型的分数阶系统进行仿真,验证了所提方案的优越性和有效性．      

自抗扰控制器在永磁同步电机控制中的应用

为了解决永磁同步电机(PMSM)调速系统突加负载或负载扰动时控制性能差的问题,提出用自抗扰控制技术设计PMSM控制方案.将负载突变和负载扰动归为未知扰动,用自抗扰控制器进行估计、补偿和控制.仿真结果表明,该方法能够提高系统的响应速度,减小稳态误差且无超调,能有效地抑制负载变化对转速的影响.     

基于自抗扰控制技术的轧机主传动系统机电振动控制

轧机驱动电机与轧辊间采用长轴连接,连接轴刚度有限,因此在带材高速轧制时,常规电流、转速双闭环控制易产生机电振动和断带现象.为了克服该缺陷,针对轧机主传动系统精确模型不易获得的特点,将不确定外扰和未建模动态视为一个综合扰动项,运用扩张状态观测器对系统状态和综合扰动项进行观测,设计了轧机主传动机电振动扩张状态观测器控制系统;进一步利用自抗扰控制技术设计了一个不依赖于对象模型的轧机主传动机电振动控制系统.仿真研究结果表明:两种控制系统都有效改善了轧机主传动系统的跟踪性能,抑制了系统的机电振动现象,同时对系统内部参数如轧辊转动惯量等的摄动也具有较强的鲁棒性.首次将扩张状态观测器和自抗扰控制技术应用到轧机主传动机电振动控制系统中,并通过与传统电流、转速双PI控制和基于降维状态观测器的状态反馈控制比较,证明了该方法的有效性和优越性.     

基于自抗扰控制技术的电子节气门控制

为解决传统线性控制器无法满足汽车电子节气门控制要求的问题,利用自抗扰控制技术进行了电子节气门非线性控制器研究。首先根据博世公司的电子节气门性能指标,给出了参考过渡过程和采样时间的选取准则;然后通过将建模误差等不确定性看作加性外部扰动,利用扩张状态观测器实时估计出作用于系统的扰动总和,并给予补偿。仿真表明,基于自抗扰控制技术的控制方法能够很好地实现电子节气门的快速跟踪控制,而且具有较强的鲁棒性。     

循环流化床锅炉汽温系统的自抗扰控制

循环流化床汽温系统存在大滞后、大延迟、多时变、非线性等诸多问题,针对含时滞的回路,实施自抗扰控制,设计循环流化床锅炉(CFBB)串级汽温自抗扰控制系统,利用新型自抗扰控制器参数整定方法优化控制器参数,进行跟踪实验、扰动实验和鲁棒性实验。仿真结果表明:自抗扰控制技术能够使CFBB汽温控制系统的动态性能得到改善,过渡过程更加平稳,系统输出几乎没有超调,调节时间缩短,并且自抗扰控制器对被控对象参数变化有较好的性能鲁棒性。本文方法的有效性和适用性,为提高循环流化床锅炉汽温控制系统的控制品质提供新的思路。     

永磁同步风力发电机的时滞补偿自抗扰控制设计

针对直驱式永磁同步风力发电机系统存在非线性、多变量、强耦合、模型不确定和控制时延等问题,提出一种基于时滞补偿的自抗扰控制策略.该策略首先利用Smith预估器补偿时延,使自抗扰控制器作用于无时延环节,然后引入非线性扩张状态观测器对建模误差和多变量耦合等内部干扰以及外部环境的不确定性进行估计,并通过前馈通道进行实时补偿,消除内外干扰的影响,实现最大功率跟踪,最后基于Matlab/Simulink系统展开对比验证.结果表明:该控制策略能有效提高系统的稳定性和抗干扰能力,其跟踪性能优于传统自抗扰控制方法.     

球磨机制粉系统的线性自抗扰控制

球磨机制粉系统具有大惯性、大时滞和强耦合等特点,很难建立精确的数学模型。本文分析了球磨机制粉系统的动态特性,并为其设计分散线性自抗扰控制方案。该方案综合分散控制和线性自抗扰控制器的优点,结构简单,不依赖于对象精确模型,可以对被控对象中存在的耦合、干扰和不确定性等进行估计并补偿。根据实际现场要求,对球磨机制粉系统进行设定值跟踪实验、输入扰动实验和性能鲁棒性实验,并比较所设计方案与PID方案的控制性能。结果表明,分散线性自抗扰控制具有更强的解耦能力和抗干扰能力,且性能鲁棒性更优。     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

正~~     

An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.     

Tracking data management using topology of moving object database system for moving object constrained trajectory in LBS application

Advances in wireless technologies and positioning technologies and spread of wireless devices, an interest in LBS (Location Based Service) is arising. To provide location based service, tracking data should have been stored in moving object database management system (called MODBMS) with proper policies and managed efficiently. So the methods which acquire the location information at regular time intervals then, store and manage have been studied. In this paper, we suggest tracking data management techniques using topology that is corresponding to the moving path of moving object. In our techniques, we update the MODBMS when moving object arrived at a street intersection or a curved road which is represented as the node in topology and predict the location at past and future with attribute of topology and linear function. In this technique, location data that are corresponding to the node in topology are stored, thus reduce the number of update and amount of data. Also in case predicting the location,because topology are used as well as existing location information, accuracy for prediction is increased than applying linear function or spline function.