基于体感机械臂的舒适控制算法设计研究

分析人体手臂在体感控制中的舒适程度,依据疲劳度理论建立手臂舒适范围空间模型。采用体感方式控制机械臂运动,通过径向测试实验与点阵指定实验测试手臂的舒适参数,拟合控制映射函数,提出基于体感机械臂的舒适控制算法。通过动作跟踪与远程抓物实验,测得用舒适算法控制机械手的相对误差在5%以内,尖端位置绝对误差在2 mm以内,舒适度比传统控制算法提高51.8%,在满足体感控制准确度的基础上较大程度保证了使用者的舒适性,提高了体感控制效率。     

基于限幅加权骨骼节点滤波的体感交互技术

为了改善机器人的操作方式,提高体感交互的识别精度,提出了一种基于限幅加权骨骼节点滤波的体感交互技术。首先利用Kinect传感器获取深度场景信息,并通过骨骼追踪技术处理所获得的深度信息以此匹配人体各个关节,建立人体各关节的3D坐标;然后采用空间向量映射的形式计算出各关节转动角度,并利用本文所提出的限幅加权滤波算法,即通过对采集并计算出的关节转动角度进行限幅加权滤波处理,减少了骨骼噪声的影响;最后将转动角度转化为控制指令,通过蓝牙串口将控制指令发送给机械臂控制器,操控机械臂舵机转动。实验结果表明,该方法能够实现体感交互效果,机械臂随人体手臂运动的识别率为96.3%,且限幅加权滤波算法能有效减少骨骼噪声影响。     

基于手臂体感器与机械臂的人机交互系统设计

本文所设计的系统主要通过手臂体感器获取手臂的移动情况,利用信息捕捉加坐标转化的方法,转化为相应的指令传输到机械臂的系统中,使得机械臂能在非特殊情况下,按照手臂的运动轨迹做相应的运动.获取移动轨迹的途径由手臂体感器提供,并将之体现为三维空间中的坐标,使得机械臂的运动更加接近手臂的运动,为进一步的研究开发建立了基础.     

基于事件触发的神经网络控制器稳定性分析

针对非线性系统稳定性问题,设计了基于事件触发的神经网络控制器来稳定非线性系统,控制器只有在触发规则满足的条件下,才更新控制参数,降低了网络传输率。算法开始先建立非线性系统模型,在采样过程中引入事件触发机制,并且设计了神经网络控制器,对于系统中包含的传输时滞,引入系统时滞模型,运用输入延迟法将同步控制器求解问题转化为时滞系统的稳定性问题。再通过构造分段Lyapunov-Krasovskii泛函并结合Jensen不等式,给出了非线性系统稳定条件。与传统数据采样系统相比,本文所提出的方法有效地增大了采样间隔,结尾通过例子仿真验证了所提出方法的有效性。     

未知非线性零和博弈最优跟踪的事件触发控制设计

设计了一种基于事件的迭代自适应评判算法,用于解决一类非仿射系统的零和博弈最优跟踪控制问题.通过数值求解方法得到参考轨迹的稳定控制,进而将未知非线性系统的零和博弈最优跟踪控制问题转化为误差系统的最优调节问题.为了保证闭环系统在具有良好控制性能的基础上有效地提高资源利用率,引入一个合适的事件触发条件来获得阶段性更新的跟踪策略对.然后,根据设计的触发条件,采用Lyapunov方法证明误差系统的渐近稳定性.接着,通过构建四个神经网络,来促进所提算法的实现.为了提高目标轨迹对应稳定控制的精度,采用模型网络直接逼近未知系统函数而不是误差动态系统.构建评判网络、执行网络和扰动网络用于近似迭代代价函数和迭代跟踪策略对.最后,通过两个仿真实例,验证该控制方法的可行性和有效性.     

自动化控制下机械手臂运动轨迹研究

对机械手臂运动轨迹进行优化控制,能改善机械手臂的自动控制性能。为了提高机械臂的控制稳健性,提出一种基于变结构模糊PID控制的机械手臂运动轨迹优化控制模型。首先采用末端效应逆运动学模型构建机械手臂的运动规划约束参量数学模型,采用七自由度运动空间重构方法建立机械手臂运动的动力学方程。然后通过纵向定常运动,分析建立机械手臂整定控制目标函数,求解机械臂在抓取作业过程中的最佳导引控制律,采用变结构模糊PID控制方法进行运动轨迹的误差修正,实现机械臂自动控制优化。最后通过仿真实验进行控制性能测试,结果表明,采用该方法进行机械手臂运动轨迹控制的精度较高,对机械臂位形变化轨迹的预测准确性较好。     

不稳定时滞对象的最优鲁棒二自由度控制器解析设计

针对不稳定时滞对象提出一种二自由度控制器解析设计方法．通过内模控制规律进行控制器设计,改进内模控制的滤波器提高系统的鲁棒性及其性能．同时对系统的稳定性、鲁棒性及性能进行分析,提出了严格基于模型信息的鲁棒指标选择规则,保证系统获得良好的鲁棒/性能平衡．最后,将控制器的参数整定转化为一个约束优化问题,提出控制器解析整定方法,并通过仿真实例验证该方法的有效性．     

科学计算应用程序单核指令级优化研究

尽管高性能计算机性能提升越来越快,但科学计算应用程序获得同步的性能提升是很困难的.提高科学计算应用程序的执行性能,需要依照高性能计算机体系结构的特点进行针对性的优化,其中单核指令级优化是科学计算应用程序性能优化的重要方面之一.以基于JASMIN(J adaptive structured meshes applications infrastructure)框架实现的Euler程序为例,探讨了科学计算应用程序在Intel Xeon微处理器平台上的具体性能问题和指令级并行性能优化方法,并较大幅度地优化了Euler程序的单核性能.程序优化后,二维和三维两个物理模型计算的总运行时间比优化前减少了21%~34%,核心模块Gas1dapproxy的执行时间缩短了50%以上.性能优化实验表明:流水线效率已成为影响科学计算类实际应用程序计算效率的重要因素,需要通过降低计算语句的依赖度、减少长延迟计算数量等方法予以改进.     

级联触发策略下非结构化道路的自主卡车队列控制

本文针对非结构化道路上自主卡车队列系统的控制问题进行研究, 设计一种基于级联触发的控制器,有效提高复杂工况下的卡车队列系统性能. 首先, 建立不依赖于道路结构的纵–横耦合卡车队列系统模型, 该模型涉及复杂环境下车辆存在故障(包括执行器、传感器的失效故障以及随机网络故障)影响. 其次, 为降低燃油消耗, 设计了基于自触发和事件触发的级联触发控制器, 并利用李雅普诺夫方法证明了系统的闭环稳定性. 此外, 通过对系统Zeno行为的分析量化, 得到了触发时间间隔的下界值, 保证了算法的实际应用性. 本文为了实现卡车系统队列稳定性控制目标, 进一步给出了控制器设计限制条件. 最后, 仿真结果表明, 所提出的控制方法不但能保证单车渐近稳定以及队列稳定, 还能有效减少执行器更新频率, 提高燃油经济性.     

Delphi中使用图形资源

所有Ｗｉｎｄｏｗｓ应用程序都将使用各种类型的资源文件,其中包括自定义的外部资源文件,来改善窗口界面的视觉效果。本文利用光标及图标的自定义图形资源,在应用程序中实现以下功能：为窗体内各组件设置不同的自定义光标;转换菌体中的图标显示;在任务栏中显示指示图标。本文用Ｄｅｌｐｈｉ４０语言编程,应用程序在微机上通过调试。１应用程序与自定义光标应用程序通过ＬｏａｄＣｕｒｓｏｒＦｒｏｍＦｉｌｅ函数加载一个外部的光标文件,将其定义为设置屏幕状态ＴＳｃｒｅｅｎ类的Ｃｕｒｓｏｒｓ属性值,以便在应用程序中添加一个自定…     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.     

Editorial: Special issue on recent advances in hybrid control theory and applications

正The demands of a rapidly advancing technology for faster and more accurate controllers have always had a strong influence on the progress of automatic control theory.In recent years control problems have been arising with increasing frequency in widely different areas,which cannot be addressed using conventional control techniques.The principal reason for this is the fact that a highly competitive economy is forcing systems to operate in regimes where     

Information for Authors

正Aim The Journals of Zhejiang University-SCIENCE(A/B/C)areedited by the international board of distinguished Chinese andforeign scientists,and are aimed to present the latest devel-opments and achievements in scientific research in China andoverseas to the world’s scientific circles,especially to stimulateand promote academic exchange between Chinese and for-eign scientists everywhere.     

Enhancing a leaf radiative transfer model to estimate concentrations and in vivo specific absorption coefficients of total carotenoids and chlorophylls a and b from single-needle reflectance and transmittance

The relative concentrations of different pigments within a leaf have significant physiological and spectral consequences. Photosynthesis, light use efficiency, mass and energy exchange, and stress response are dependent on relationships among an ensemble of pigments. This ensemble also determines the visible characteristics of a leaf, which can be measured remotely and used to quantify leaf biochemistry and structure. But current remote sensing approaches are limited in their ability to resolve individual pigments. This paper focuses on the incorporation of three pigments—chlorophyll a, chlorophyll b, and total carotenoids—into the LIBERTY leaf radiative transfer model to better understand relationships between leaf biochemical, biophysical, and spectral properties.Pinus ponderosa and Pinus jeffreyi needles were collected from three sites in the California Sierra Nevada. Hemispheric single-leaf visible reflectance and transmittance and concentrations of chlorophylls a and b and total carotenoids of fresh needles were measured. These data were input to the enhanced LIBERTY model to estimate optical and biochemical properties of pine needles. The enhanced model successfully estimated reflectance (RMSE = 0.0255, BIAS = 0.00477, RMS%E = 16.7%), had variable success estimating transmittance (RMSE = 0.0442, BIAS = 0.0294, RMS%E = 181%), and generated very good estimates of carotenoid concentrations (RMSE = 2.48 µg/cm², BIAS = 0.143 µg/cm², RMS%E = 20.4%), good estimates of chlorophyll a concentrations (RMSE = 10.7 µg/cm², BIAS = − 0.992 µg/cm², RMS%E = 21.1%), and fair estimates of chlorophyll b concentrations (RMSE = 7.49 µg/cm², BIAS = − 2.12 µg/cm², RMS%E = 43.7%). Overall root mean squared errors of reflectance, transmittance, and pigment concentration estimates were lower for the three-pigment model than for the single-pigment model. The algorithm to estimate three in vivo specific absorption coefficients is robust, although estimated values are distorted by inconsistencies in model biophysics. The capacity to invert the model from single-leaf reflectance and transmittance was added to the model so it could be coupled with vegetation canopy models to estimate canopy biochemistry from remotely sensed data.     

Mr. Twinn’s bombes

This article discusses the history and design of the special versions of the bombe key-finding machines used by Britain’s Government Code & Cypher School (GC&CS) during World War II to attack the Enigma traffic of the Abwehr (the German military intelligence service). These special bombes were based on the design of their more numerous counterparts used against the traffic of the German armed services, but differed from them in important ways that highlight the adaptability of the British bombe design, and the power and flexibility of the diagonal board. Also discussed are the changes in the Abwehr indicating system that drove the development of these machines, the ingenious ways in which they were used, and some related developments involving the bombes used by the U.S. Navy’s cryptanalytic unit (OP-20-G).