柔性机械臂振动控制系统的实验研究

本文为避开柔性机械臂传统建模的繁锁性及精确性的要求，研究柔性机械臂振动的控制规律，对并置式ＰＩＤ控制的柔性机械臂进行了系统的实验研究，包括电机轴驱动力矩和梁末端加速度响应的检测，调整系统的控制增益或运动参数，可实现柔性机械臂振动的有效抑制，通过一系列的实验研究，揭示了柔性臂振动控制规律－力相位制律，为柔性机械臂振动控制及其控制器的设计指明了方向，本实验研究亦可验证理论模型。     

气动机械臂模糊控制的研究

研究气动机械臂的模糊控制原理和实现方法，设计了机械臂的气压驱动伺服控制回路，并进行了实验研究，结果表明，模糊控制能使气动机械臂获得良好的控制性能。     

一种串联式液压机械臂PLC运动控制方法研究

串联式液压机械臂是一个复杂的连杆控制机构，针对复杂多变的运行工况下串联式液压机械臂的运动控制精确化需求，在串联式液压机械臂工作原理和运动控制系统结构基础上，构建了PLC主从式控制系统图，并设计了PLC控制程序，优化了运动控制系统的标定参数，在搭建好的串联式液压机械臂运动控制实验台架中进行调试测试，最后实验结果表明该控制方法能够快速提高串联式液压机械臂的运动控制精度，提升运动控制系统的响应能力。     

一重载高速机械臂的结构与控制同时设计

拟订了机械臂的工作原理，建立了机械臂的受控动力学方程，运用优化算法设计了PD控制器的增益，计算了机械臂在不同角度下的刚体动力学响应。为了确定合理的机械臂截面尺寸，运用有限元法建立了机械臂的弹性动力学方程，求解了不同截面尺寸下的机械臂弹性动力响应，评价了机械臂的弹性振动。实践证明，所确定的机械和控制设计方案满足设计要求。     

基于PLC的液控分拣机械臂设计与研究

随着科学技术水平的提高，机械臂逐渐代替人力应用于工业生产中，实现货物的装卸、搬运及分拣等工作。传统球坐标机械臂由于承受自重及货物负载，导致转动角度及控制精度较差。对此，基于传统球坐标机械臂及PLC控制原理，设计了新型五自由度液控机械臂。该机械臂以液压为驱动力，通过PLC控制程序实现对机械臂的运动控制，完成生产线中物料的自动分拣，其应用大幅降低了人工劳动强度，提高了生产效率。     

基于故障在线估计的欠驱动机械臂容错控制方法

为了提高机器人机械臂故障曲线跟踪准确性，本文设计了基于故障在线估计的欠驱动机械臂容错控制方法。分析机器人欠驱动机械臂关节故障原理，建立动力学模型实现对关节故障的检测。采用分散控制的思想将机器人欠驱动机械臂容错控制分为故障检测、信号重构、取代控制以及反馈控制四个部分，依据这四部分设计容错控制律，实现对速度信号与错误信息的实时反馈。在此基础上，通过干扰观测器实现控制律的干扰补偿，使容错控制后的机器人欠驱动机械臂具有抗外界干扰能力，以此完成控制方法设计。分析实验结果可知，所提方法不仅提高了故障曲线跟踪的准确性，减少了欠驱动机械臂容错控制后的稳态时间，满足了机器人欠驱动机械臂容错控制设计需求。     

机械臂的设计及其动力学仿真

所研究的机械臂是工业生产线上负责传送物料的装置，它是一种集机械、自动控制和液压传动为一体的机械系统。作者阐述了机械臂这类受控机械系统动力学计算的基本原理，运用机械系统动力学仿真软件ADAMS，建立了机械臂的机械与液压相互耦合及机械与控制相互耦合的动力学模型，获得了机械臂工作时各参数随时间的变化规律，对液压和控制子系统的动力学特性进行了计算和分析。     

带有加速度反馈的柔性机械臂开关变结构控制

为了实时控制柔性机械臂的残余振动，提高定位精度，提出了带有加速度反馈的开关变结构控制，将柔性机械臂的运动过程分成两部分，第一部分使其在控制力矩作用下做大角度刚体运动；第二部分，当柔性机械臂的运动临近终止状态时，通过逻辑开关，将柔性机械臂末端加速度反馈量接通，　以产生抑制弹性振动的控制力矩，与刚体运动的控制力矩迭加，完成终点定位和振动抑制。一系列的试验包括与ＰＩＤ控制的比较证明带有加速度反馈的柔性机械臂开关变结构控制对于抑制柔性臂残余振动是有效和实用的。     

基于PLC技术的重载混联式液压机械臂运动优化控制方法研究

重载混联式液压机械臂运行在复杂多变的工作环境下，高负荷运行需要稳定的运动控制。针对重载混联式液压机械臂可变工况下运动控制失稳现象，在液压机械臂系统结构和动力学分析的基础上，对液压机械臂的模块间通讯进行优化，构建了基于CANopen的分布式通讯结构；利用PLC作为运动优化控制技术，设计了双闭环的运动控制策略；在真实模拟的重载混联式液压机械臂运动控制试验环境中验证控制方法的可靠性。实验结果分析可以看出，该控制方法能够快速的提升重载混联式液压机械臂运动稳定性和动态响应能力。     

软腔体柔性机械臂的T-S模糊建模与控制

针对柔性机械臂强非线性、强耦合性及不确定性的特点，利用Takagi—Sugeno模糊模型其规则前件是模糊变量，而规则后件的结论是输入输出线性函数的特点，对柔性机械臂进行了建模。在验证了模型准确性的基础上，进行了广义预测控制方法的研究，最后，对比分析了广义预测控制和传统PID控制，实验结果表明，基于T—S模糊模型的广义预测控制能很好的实现对柔性机械臂的控制。为柔性机械臂的模糊建模和进一步研究提供了理论指导及重要的前提条件。     

Mice embryology: A microscopic overview

In this work, we studied the embryology of mice of 12, 14, and 18 days of gestation by gross observation, light microscopy, and scanning electron microscopy. Grossly, the embryos of 12 days were observed in C‐shaped region of the brain, eye pigmentation of the retina, first, second, and third pharyngeal arches gill pit nasal region on the fourth ventricle brain, cervical curvature, heart, liver, limb bud thoracic, spinal cord, tail, umbilical cord, and place of the mesonephric ridge. Microscopically, the liver, cardiovascular system and spinal cord were observed. In the embryo of 14 days, we observed structures that make up the liver and heart. At 18 days of gestation fetuses, it was noted the presence of eyes, mouth, and nose in the cephalic region, chest and pelvic region with the presence of well‐developed limbs, umbilical cord, and placenta. Scanning electron microscopy in 18 days of gestation fetuses evidenced head, eyes closed eyelids, nose, vibrissae, forelimb, heart, lung, kidney, liver, small bowel, diaphragm, and part of the spine. The results obtained in this work describe the internal and external morphology of mice, provided by an integration of techniques and review of the morphological knowledge of the embryonic development of this species, as this animal is of great importance to scientific studies. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc.     

聚焦型微通道内气泡生成特性数值模拟

微气泡因具有比表面积小和稳定性好等特点被广泛应用于污水处理和矿物浮选等领域。为了高效获得稳定的微气泡,利用COMSOL软件研究了聚焦型微通道中气、液相流速、表面张力、液相黏度和壁面润湿性对气泡生成的影响。结果表明：当气相流速增加时,气相克服表面张力的能力增强,气泡的脱离尺寸和频率增大,脱离时间减小;液相流速增加时作用在微气泡上的惯性力和剪切力增大,气泡脱离时间和脱离尺寸均减小;表面张力增大时气泡脱离时间和脱离尺寸增大,脱离频率减小;液相黏度增大时,作用于气泡的黏性力随之增大,气泡的脱离时间和脱离直径均随之减小,脱离频率增大;接触角从40°增大到180°,气泡的脱离尺寸和脱离时间整体先增大后减小,脱离频率先减小后增大。     

The actuality and progress of whole sky infrared cloud remote sensing techniques

Clouds are crucial regulators of both weather and climate. Properties such as the amount,type,height,distribution and movement of them have an impact on the earth's radiation budget and the hydrological cycle,thus cloud observation is very important. The disadvantages of zenith pointing measuring instruments and whole sky visible imagers limit the application of them.A summary of the actuality and application of ground-based whole sky infrared cloud measuring instruments and analyses of the techniques of radiometric calibrations,removal of atmospheric emission and calculation of cloud cover,amount,type are conducted to promote the automatically observation of the whole sky. Fully considering whole sky infrared cloud sounding theories,techniques and applications,there are still a lot of studies on improving the properties of instruments,enhancing the techniques of cloud base height measurements and establishing instrumental cloud classification criterion before actual operations.     

大尺度构件重载高精加工机器人本体设计与性能提升关键技术

基于典型大尺度构件的移动机器人化加工需求背景与发展现状的总结与分析,提出了大工作空间、高刚度、高精度、重载、轻量化、高动态响应、大负载自重比的大尺度构件加工机器人本体的基本性能要求。围绕上述基本性能要求,从机器人本体构型与机构优化设计,高性能加工机器人专用控制器与加工机器人操作系统开发,加工机器人运动学参数动态标定及位姿误差实时预测与动态补偿,刚柔耦合多体动力学建模,机器人动力学控制及主动振动控制等方面,论证了重载高精度加工机器人本体的优化设计及机器人性能提升方法,并完成了大尺度构件加工机器人本体构型与机构的概念设计。大尺度构件加工机器人本体的创新设计与研制,可为航空航天等领域的典型大尺度构件提供高性能的超柔性机器人化加工系统,并有助于推动国产工业机器人关键性能的提升。     

微波滤波器的装调融合建模与反演

微波滤波器作为关键的选频装置,在设计制造周期中存在一些突出问题,如设计制造周期数据割裂以及数据缺乏有效利用,从而导致设计制造阶段脱节,降低了设计制造迭代效率。文中提出了一种微波滤波器装调融合建模与反演方法,根据滤波器的设计信息、制造数据以及滤波器机理采用自顶向下的方式构建滤波器知识图谱,利用知识图谱对微波滤波器的数据与机理进行规范化存储;利用机理数据融合建模的方法构建微波滤波器正向演进模型;基于正向演进模型,结合渐进空间映射算法,构建微波滤波器快速装调反演模型。演进与反演实验结果表明,预测电性能与实际电性能基本重合,故障滤波器通过两次装调即可满足设计指标。该方法能够实现微波滤波器设计制造数据的有效关联、微波滤波器性能演进的有效预测以及快速装调反演,提高了设计制造周期数据的利用率,增强了滤波器设计与制造的协同。     

XPN-FMS: A CAD tool for FMS modeling, analysis, animation, and simulation using Petri nets and X window

We propose a CAD tool, XPN-FMS, which is primarily based on a unique Petri net (PN) synthesis method, called the knitting technique, developed by the authors. Petri net theory has been applied to specification, validation, performance analysis, control code generation, and simulation for manufacturing systems. The analysis of flexible manufacturing systems (FMSs) based on PNs suffers from the complexity problem of reachability analysis (Peterson, 1981). CAD tools are urgently needed. There is no existing CAD tool for FMSs as comprehensive as XPN-FMS, in the sense that the latter integrates the functions of drawing, analysis, reduction (Chao and Wang, 1992; Murata and Koh, 1980), synthesis, property queries, and animation of FMS operations in one software package. Using the X window graphical interface and animation, XPN-FMS makes the modeling and analysis of an FMS visualizable and easy to understand and manipulate. It lets a user draw the factory layout of an FMS on the screen of a monitor using the supplied tools. A corresponding PN model can also be drawn on the monitor screen. XPN-FMS can animate and simulate the overall operating process of the FMS. It is useful for FMS specification, validation, and exploration of different design alternatives, status monitoring, and control. Using XPN-FMS with various inputs and comparing the resulting outputs, the user can determine how to improve efficiency, reduce cost, and pinpoint bottlenecks. For the PN models of FMSs that are decision free, we extend the theory and algorithm of a unique matrix-based method (Chao and Wang, 1993b) to search for subcritical loops (including types A and B) and to support scheduling and dealing with transition periods. XPN-FMS implements this extended method to find the minimum cycle time, critical loop, subcritical loops, next critical loop, and scheduling ranges to avoid the transient period for static scheduling. This is implemented in XPN-FMS for the input sequence control.This project is partially funded by NJIT's Separately Budgeted Research Program. Portions of this article were presented in Chao, Chen, Wang, and Zhou (1992),Proceedings of the 1992 IEEE International Conference on Systems, Man, and Cybernetics, Chicago, Illinois, October 1992. The former name of the first author, which has appeared in some of his earlier publications, was Yuh Yaw.     

一种新型弱耦合三平移并联机器人机构及其运动学分析

提出一种弱耦合2RRPaR+PPaP三平移操作机器人机构,分析了机构的自由度及拓扑结构特征;推导了机构的正逆解方程以及速度、加速度模型,根据速度雅可比矩阵,分析了机构的奇异位置;根据机构的逆解方程和主要约束,采用三维极坐标边界搜索法绘制了机构的工作空间三维实体图和截面图;由ADAMS三维模型仿真和运动正解方程计算所得的位移、速度、加速度曲线基本一致,验证了运动方程的正确性。该机构解耦性好、结构简单、运动灵活,在纵向移动方向上具有部分解耦和工作空间大的优点,适合用作生产线自动操作手机构。     

Contribution of high-resolution correlative imaging techniques in the study of the liver sieve in three-dimensions

Correlative microscopy has become increasingly important for the analysis of the structure, function, and dynamics of cells. This is largely due to the result of recent advances in light-, probe-, laser- and various electron microscopy techniques that facilitate three-dimensional studies. Furthermore, the improved understanding in the past decade of imaging cell compartments in the third dimension has resulted largely from the availability of powerful computers, fast high-resolution CCD cameras, specifically developed imaging analysis software, and various probes designed for labeling living and or fixed cells. In this paper, we review different correlative high-resolution imaging methodologies and how these microscopy techniques facilitated the accumulation of new insights in the morpho-functional and structural organization of the hepatic sieve. Various aspects of hepatic endothelial fenestrae regarding their structure, origin, dynamics, and formation will be explored throughout this paper by comparing the results of confocal laser scanning-, correlative fluorescence and scanning electron-, atomic force-, and whole-mount electron microscopy. Furthermore, the recent advances of vitrifying cells with the vitrobot in combination with the glove box for the preparation of cells for cryo-electron microscopic investigation will be discussed. Finally, the first transmission electron tomography data of the liver sieve in three-dimensions are presented. The obtained data unambiguously show the involvement of special domains in the de novo formation and disappearance of hepatic fenestrae, and focuses future research into the (supra)molecular structure of the fenestrae-forming center, defenestration center and fenestrae-, and sieve plate cytoskeleton ring by using advanced cryo-electron tomography.     

Histochemical and ultrahistochemical localization of heavy metals in calf organs

Cadmium, zinc, selenium, and copper were administered, singly or in combination, orally or subcutaneously. Experiment I included 32 calves of both sexes; six received Cd (two groups), Zn, Cd, and Zn, and Cd and Se (two groups) and one group was a control. In Experiment II (21 bulls), three were given Cd, Cd, and Cu, and Cd and Zn, respectively, and one group was a control. For light microscopy, in Experiment I the highest amounts of silver granules were present in the samples of liver, small intestine, and vesicular gland of all the exposed groups; in Experiment II the most affected organs were liver, kidney, and small intestine. For electron microscopy, in Experiment I, after administration of Cd and Zn, the highest amounts of granules were seen in the cytoplasm of hepatocytes and cells of the proximal and distal renal tubules and the lowest amounts were found in glandular cells of the pancreas. Administration of Cd and Se resulted in the presence of large numbers of granules in the nuclei and nucleoli of spermatogonies. In Experiment II, ingestion of Cd and Zn in feed led to the appearance of highest amounts of granules in the nucleoli, nuclei, and cytoplasm of cells in testes, kidneys, and pancreas. Following Cd intake, the highest accumulation of granules was observed in the nucleoli of hepatocytes and cells of the proximal and distal renal tubules. Combined Cd and Cu produced the highest number of granules in cells of the proximal and distal renal tubules and in the nucleoli and nuclei of germinal epithelium.     

振动子结构综合与修正方法研究综述

在大型复杂的结构设计过程中,子结构综合与修正方法由于其快速、动态、综合等特点越来越广泛地应用于现代结构设计之中,以完善子结构综合与修正方法知识参考、引起国内学者关注该技术研究为目的,阐述了振动子结构与系统之间的综合与修正方法。在子结构综合方法中,主要对比分析了模态缩减与综合、频域JETMUNDSEN、REN、机械阻抗导纳法综合法、频响函数奇异值分解降噪法、子系统转角自由度刚柔等效及转换方法的原理及应用,评述了上述方法的优点与不足,就尚未解决的问题作了进一步探讨;在子结构修正方法中,对比分析了多重参考基准修正法、目标函数动态修正法、参数型修正、神经网络型修正、灵敏度修正、频响函数修正等方法的应用,总结了模型修正方法中存在的一些问题。最后,提出了振动子结构综合及修正方法的研究趋势。