电液伺服系统内模控制

针对电液位置伺服系统,提出了一种内模控制器设计方法.内模控制作为一种先进控制策略,其设计思路是将对象模型与实际对象相并联,控制器逼近模型的动态逆.考虑到内模控制对系统模型精度要求不高的特点,本文降阶简化了电液伺服系统的模型.基于此模型所设计的控制器,只有一个可调参数,且该参数直接与系统的动态特性和鲁棒性相关,整定方便,避免了控制器整定的随机性与复杂性.仿真研究和实验结果表明,内模控制可以有效地克服参数变化对系统性能的影响,使系统同时具有良好的目标值跟随特性和鲁棒性,实现了调炮误差小于±0.36mrad的高精度要求.     

时滞光电跟踪系统鲁棒内模PID控制器设计

针对时滞光电跟踪提出了一种内模PID(IMC-PID)控制器设计与参数整定的解析方法.首先建立了系统的一阶时滞积分(FODI)模型,并用二阶加时滞(SOPDT)模型进行逼近,然后利用一阶Taylor表达式代替系统模型中的时滞项,导出了控制器参数的整定规则.特别是为了保证系统的鲁棒性,可以根据最大灵敏度解析计算内模PID控制器的可调参数λ_n.仿真结果表明,与常规方法相比,所提方法不仅提供了较好的设定值跟踪和扰动抑制特性,而且对于系统参数摄动具有更好的鲁棒性.另外,实验结果也证实了该方法能够提高系统跟踪性能和跟踪精度.     

一种基于内模控制的分数阶控制器设计

目的为了解决分数阶控制器参数整定复杂问题,引入内模控制思想,从而得到分数阶内模控制器控制的被控对象。方法依据最大灵敏度整定所得分数阶内模控制器中的参数,避免参数整定的盲目性。结果相对于传统的分数阶控制器,基于内模控制思想设计得到的分数阶内模控制其设定值跟踪及抗干扰性能更优。结论仿真结果表明基于文中方法设计所得的分数阶内模控制器在模型失配时,仍具有较好的鲁棒性和控制精度。     

基于未知系统动态估计器的柔性关节机械臂funnel控制

针对带有模型不确定和外部干扰的柔性关节机械臂,提出一种基于未知系统动态估计器的funnel控制方法.基于低通滤波器设计未知系统动态估计器,用于估计模型不确定和外部干扰,该估计器结构简单,仅有一个可调参数.构造带有时变约束边界的新型funnel变量,保证系统跟踪误差被限制在预先设定的边界内,进而改善系统瞬态性能.在此基础...     

带继电反馈的Smith内模控制器设计

介绍了一种基于内模设计的Smith预测控制器的设计方法．该方法通过继电反馈实验获取过程对象的模型参数,并融入了自适应的控制思想,能较好地解决模型失配问题．实验结果表明,该控制器算法简单,容易实现,对延时较大的系统有很好的控制效果．     

光电平台伺服系统自抗扰滑模控制

提出一种基于参考模型的自抗扰滑模控制器,它包括一个自抗扰控制器和一个全局滑模控制器.根据参考模型,利用跟踪微分器设计自抗扰控制器,控制参考模型的输出精确跟踪指令输入信号.全局滑模控制器控制伺服系统被控对象的输出高精度跟踪参考模型的输出.光电平台伺服系统的实验结果证明该新型控制器能有效补偿系统的参数不确定性和非线性扰动,提高了伺服系统的跟踪精度.系统具有全局鲁棒性.     

提高光电经纬仪跟踪快速运动目标能力的一种方法

考虑到系统稳定性，光电经纬仪跟踪伺服系统一般设计成Ⅰ型系统。Ⅰ型系统存在速度、加速度动态滞后误差。动态滞后误差的大小不但与跟踪系统有关，还与目标运动特性有关。在跟踪快速运动目标时，会因速度、加速度动态误差的增大，导致目标脱离视场，丢失目标。因此提高光电经纬仪跟踪快速运动目标的能力，一直是光电跟踪伺服系统努力的方向。本文给出了一种提高光电经纬仪跟踪快速运动目标的能力的方法：动态1 Ⅰ控制法，并利用SIMULINK建立了跟踪伺服系统动态1 Ⅰ控制法仿真模型。仿真结果表明动态1 Ⅰ控制法是一种提高光电经纬仪踊跃快速运动目标能力的有效方法。     

基于改进内模的纸浆浓度控制

目的为改善纸浆浓度控制系统的大滞后性、非线性和时变性,以提高纸浆浓度的控制性能。方法针对纸浆浓度控制问题提出一种改进的内模控制,该方法首先引进导引曲线将原来的目标控制改成过程控制,解决系统快速性与超调之间的矛盾;然后再引进被控对象的参考模型与给定滞后,将导引输出与参考模型取偏差作为控制回路A,再将给定滞后与被控对象取偏差作为控制回路B;最后再基于内模控制的原理分别针对回路A与回路B设计内模控制器,将二者控制器的输出取和作为总的控制器。结果通过Matlab仿真软件搭建改进内模控制的纸浆浓度系统仿真平台,并与传统控制进行对比,仿真结果表明,系统的响应速度、跟踪性能、鲁棒性和抗干扰特性均优于传统的控制方法。结论通过仿真验证了改进内模控制在纸浆浓度控制系统上的有效性和可行性,能够明显提高系统的综合性能指标。     

重复控制逆变器并网电流控制技术研究

针对在逆变电源系统中因模型的不精确及系统负载的非线性、以及常规方法中基于完美对消思想设计的重复控制器无法满足逆变电源的控制需求且设计复杂等问题,提出一种新的重复控制器设计方法,利用数字滤波器代替重复控制补偿器,并将内模系数和补偿器等效为同一个低通滤波器。将改进后的重复控制器与PI控制相结合,形成复合式控制系统,进一步提高电流跟踪速度,减小电流谐波含量。并通过运行Matlab仿真模型和具体实验平台测试,验证该方法的可行性和良好性能。     

基于Workbench的粘箱机推动臂强度分析与优化设计

目的 为提高肥料包装计量精度,设计一种肥料包装机控制系统。方法 建立肥料动态称量系统数学模型。结合模糊控制和内模控制理论的先进控制算法,设计肥料包装计量精度控制系统。采用内模控制使PID控制器参数简化,同时模糊控制的引入实现了控制参数的在线调整。利用肥料质量偏差及其变化率,基于Mamdan二维模糊控制器实现内膜控制参数λ的自动调整。结果 实验结果表明,在模糊内模PID控制下,质量最大相对误差为1%;质量绝对误差的平均值为0.2 kg;控制算法超调量较小、具有很好的动静态性能;系统称量误差大幅度减小。结论 所述控制方法和系统可以提高称量包装设备的效率和精度。     

Action research in information systems design

This is the second of two papers on research in information systems design. The first looked at current problems in the design of computer-based information systems and at the threads in the design process, ie the designer, the methodology and the situation. The outcome was a proposal for methods of information systems analysis and design which took account of the various different viewpoints of the proposed system (the organization, the information model, the socio-technical system, the human-computer interaction and the technical perspective). The proposal needed to be tested and the only real test would have to be a real-life design exercise in which the proposed methods were used. This paper describes how the author selected a method of testing the proposed methods and the action research project that was undertaken.     

The methodological basis for information systems design

The development of computer-based information systems has always been a complex task demanding high-level skills on the part of the designers. And yet there is still confusion about the meaning of design, and its associated skills, in this area. This paper addresses the ways in which methodological guidelines have been proposed over recent years, and attempts to evaluate their benefits and disadvantages. It draws conclusions about the future directions of design strategies for producing information systems.     

Constructing the closed-form solution of control-related states real-time information for insufficient k-th order systems with one non-sharing resource to realize dynamic modeling large TNCS systems of petri nets

Since the contribution from the closed-form solution (CFS) of the number of control-related states (CRSs) of the variant k-th order system can enumerate the number of each type of CRS in real time, we can apply this real-time information to enhance the capability for dynamic modeling of such systems. For example, allocating a non-sharing waiting dummy resource (known as a deadlock thread-holder [DTH]) in each forbidden substate at that location will increase the maximum number of reachable states that can be derived using a CFS in real time. We can thus avoid the occurrence of deadlock without implementing an additional controller. To extend this capability to model a k-th order system with one non-sharing circle subnet allocated at the top position of the left-hand process (denoted as a top non-sharing circle subnet [TNCS] k-th order system) by Petri net (PN), which is the fundamental manufacturing model for different products sharing common parts, this paper extends the existing research on CFS for PNs to an insufficient k-th order system, which is the essential element for a TNCS system with one non-sharing resource. The proposed deadlock avoidance algorithm can be employed to realize the allocation of dynamic non-sharing processes.     

ATP-Responsive and ATP-Fueled Self-Assembling Systems and Materials

Adenosine triphosphate (ATP) is a central metabolite that plays an indispensable role in various cellular processes, from energy supply to cell-to-cell signaling. Nature has developed sophisticated strategies to use the energy stored in ATP for many metabolic and non-equilibrium processes, and to sense and bind ATP for biological signaling. The variations in the ATP concentrations from one organelle to another, from extracellular to intracellular environments, and from normal cells to cancer cells are one motivation for designing ATP-triggered and ATP-fueled systems and materials, because they show great potential for applications in biological systems by using ATP as a trigger or chemical fuel. Over the last decade, ATP has been emerging as an attractive co-assembling component for man-made stimuli-responsive as well as for fuel-driven active systems and materials. Herein, current advances and emerging concepts for ATP-triggered and ATP-fueled self-assemblies and materials are discussed, shedding light on applications and highlighting future developments. By bringing together concepts of different domains, that is from supramolecular chemistry to DNA nanoscience, from equilibrium to non-equilibrium self-assembly, and from fundamental sciences to applications, the aim is to cross-fertilize current approaches with the ultimate aim to bring synthetic ATP-dependent systems closer to living systems.     

基于RTLinux的模块化、网络化开放式控制器系统

现代开放式控制系统追求方便的扩展、灵活的定制、容易的移植和无缝的集成等特性。本文提出了一种基于RTLinux的开放式控制器系统(RTOC)。文章首先提出一种包含硬件平台、操作系统模块和应用软件模块的参考模型。然后,在实时操作系统RTLinux上开发完成了RTOC。由于RTLinux操作系统平台的开放性,在RTOC中,应用软件模块和操作系统模块都可以被轻松地扩展与定制。同时由于核心部分采用标准C语言进行开发,加之：RTLinux本身具有良好的可移植性,RTOC的软件部分能够很容易地移植到其它硬件平台上。为了保证模块之间的无缝连接,RTOC中实现了基于文件系统的通讯方法和硬件无关访问接口。整个系统采用层次化、模块化的设计,结构清晰,便于二次开发。同时由于RTLinux的支持和RTOC系统设计的优势,本系统具有明显的网络化特征。在RTOC执行控制任务时,关键任务会被加载到系统的核心态运行,从而保证了实时性能。最后,RTOC系统被成功地应用于虚拟漫游平台的控制试验中,证明了其具有良好开放性的优势。     

非线性弱最小相位系统的全局镇定

研究了非线性弱最小相位系统的状态反馈全局镇定问题 .在无通常要求被驱动系统全局渐近稳定的情况下 ,提出了若干全局可镇定的充分条件 .一个例子说明了本文结果的适用性     

离轴三反射镜系统研究

介绍了离轴三反射系统的两种基本离轴形式,一种是光闹离轴的有中间象面的系统,另一种是视场离轴的没有中间象面的类似于库克三片镜的系统。分析讨论了两种系统的优缺点．     

Duality in the Quantum Dissipative Villain Model and Application to Mesoscopic Josephson Junction Circuits

We study exact self-duality in the model of a Brownian particle in a washboard (WB) potential which describes a Josephson junction (JJ) coupled to an environment, for arbitrary temperature and arbitrary form of the spectral density of the environment. To this end we introduce the quantum dissipative Villain model (QDVM), which models tunneling of a degree of freedom coupled to a linear quantum environment through an infinite set of states. We derive general exact mappings on various dual discrete representations (one-dimensional Coulomb gases or surface-roughening models) which are exactly self-dual. Then we show how the QDVM maps exactly onto the WB model and use duality relations to calculate the leading terms of the total impedance of a JJ circuit, for general frequency dependence of the spectral density of the environment and arbitrary temperature.     

Reliability and risk analysis of large systems with ageing components

Applications of limit reliability functions to the reliability evaluation of large multi-state systems composed of independent components are considered. The main emphasis is on multi-state systems with ageing components because of the importance of such an approach in safety analysis, assessment and prediction, and analysing the effectiveness of operation processes of real technical systems. The results concerned with multi-state series systems are applied to the reliability evaluation and risk function determination of a homogeneous bus transportation system. Results on limit reliability functions of a homogeneous multi-state “m out of n” system are applied to durability evaluation of a steel rope. A non-homogeneous series-parallel pipeline systems composed of several lines of pipe segments is estimated as well. Moreover, the reliability evaluation of the model homogeneous parallel-series electrical energy distribution system is performed.