Finite Element Simulation Analysis of a Novel 3D-FRSPA for Crawling Locomotion

A novel three-dimensional-fiber reinforced soft pneumatic actuator(3D-FRSPA)inspired by crab claw and human hand structure that can bend and deform independently in each segment is proposed.It has an omni-directional bending configuration,and the fibers twined symmetrically on both sides to improve the bending performance of FRSPA.In this paper,the static and kinematic analysis of 3D-FRSPA are carried out in detail.The effects of fiber,pneumatic chamber and segment length,and circular air chamber radius of 3D-FRSPA on the mechanical performance of the actuator are discussed,respectively.The soft mobile robot composed of 3D-FRSPA has the ability to crawl.Finally,the crawling processes of the soft mobile robot on different road conditions are studied,respectively,and the motion mechanism of the mobile actuator is shown.The numerical results show that the soft mobile robots have a good comprehensive performance,which verifies the correctness of the proposedmodel.This work shows that the proposed structures have great potential in complex road conditions,unknown space detection and other operations.

Strategy to control crawling vehicles with automated mechanical transmission

In order to move vehicles with automated mechanical transmission （AMT） a little bit of distance, such as reversing into or moving in a garage, a control strategy for crawling vehicles was proposed. Based on the dynamic analysis of vehicle starting process and requirements of crawl driv- ing for the vehicle, a control strategy of the clutch was designed. The strategy increased the.slipping friction torque first and then decreased it, in order to realize the crawl driving. The speed increased by the engagement of the clutch, and then the clutch turned to disengage to the half disengage point, when the speed met the requirements. Based on the control strategy, a control software was de- signed. In the end, the software was tested on a vehicle with AMT. The lowest steady vehicle speed was reduced to 40% of the original value, which was set in the control strategy.

New focused crawling algorithm

Focused carawling is a new research approach of search engine. It restricts information retrieval and provides search service in specific topic area. Focused crawling search algorithm is a key technique of focused crawler which directly affects the search quality. This paper first introduces several traditional topic-specific crawling algorithms, then an inverse link based topic-specific crawling algorithm is put forward. Comparison experiment proves that this algorithm has a good performance in recall, obviously better than traditional Breadth-First and Shark-Search algorithms. The experiment also proves that this algorithm has a good precision.

Manipulation of Crawling Growth for the Formation of Sub-millimeter Long ZnO Nanowalls

Vapor-phase growth of ZnO nanowires based on gold catalyst is usually accompanied with lateral crawling growth on the substrate surface. We present results from our systematic experiments where the growth temperature and catalyst size are controlled. The data corroborate that it is possible to obtain clean vertical nanowire arrays while avoiding the crawling growth. 0% the other hand, crawling growth can be manipulated to obtain root-interconnected nanowire arrays, which could be useful for certain applications. Our results also imply that the previously suggested growth mechanism for the wire-on-wall hybridstructure might be incorrect. Finally, we show the formation of sub-millimeter long, straight ZnO nanowalls by combining a gold-catalyzed epitaxial growth of vertical nanowires and their mergence due to a confined crawling growth. These unconventional nanostructures might have unique electric or optical transport properties.

分布式Web Crawler的研究:结构、算法和策略

本文介绍了一个大型分布式Web Crawler系统——Igloo 1.2版。它采用分布式的系统结构,通过我们设计的二级哈希映射算法使系统可以进行高效的任务分割,并且系统的规模动态可扩展.爬行网页的质量是评价Crawler的一个重要指标,Igloo以PageRank值作为网页质量评价的标准,从而提高了爬行质量.加快爬行速度的关键是如何解除Crawler系统中的性能瓶颈,本文对此也作了详细的讨论,并提出了一种基于“滞后合并”策略的UBL数据库存取方法.实验表明,Igloo在保持高性能的同时能快速爬行到高质量的网页.

SmartCrawler:A Three-Stage Ranking Based Web Crawler for Harvesting Hidden Web Sources

Web crawlers have evolved from performing a meagre task of collecting statistics,security testing,web indexing and numerous other examples.The size and dynamism of the web are making crawling an interesting and challenging task.Researchers have tackled various issues and challenges related to web crawling.One such issue is efficiently discovering hidden web data.Web crawler’s inability to work with form-based data,lack of benchmarks and standards for both performance measures and datasets for evaluation of the web crawlers make it still an immature research domain.The applications like vertical portals and data integration require hidden web crawling.Most of the existing methods are based on returning top k matches that makes exhaustive crawling difficult.The documents which are ranked high will be returned multiple times.The low ranked documents have slim chances of being retrieved.Discovering the hidden web sources and ranking them based on relevance is a core component of hidden web crawlers.The problem of ranking bias,heuristic approach and saturation of ranking algorithm led to low coverage.This research represents an enhanced ranking algorithm based on the triplet formula for prioritizing hidden websites to increase the coverage of the hidden web crawler.

A Survey about Algorithms Utilized by Focused Web Crawler

Abstract—Focused crawlers （also known as subjectoriented crawlers）, as the core part of vertical search engine, collect topic-specific web pages as many as they can to form a subject-oriented corpus for the latter data analyzing or user querying. This paper demonstrates that the popular algorithms utilized at the process of focused web crawling, basically refer to webpage analyzing algorithms and crawling strategies （prioritize the uniform resource locator （URLs） in the queue）. Advantages and disadvantages of three crawling strategies are shown in the first experiment, which indicates that the best-first search with an appropriate heuristics is a smart choice for topic-oriented crawlingwhile the depth-first search is helpless in focused crawling. Besides, another experiment on comparison of improved ones （with a webpage analyzing algorithm added） is carried out to verify that crawling strategies alone are not quite efficient for focused crawling and in most cases their mutual efforts are taken into consideration. In light of the experiment results and recent researches, some points on the research tendency of focused crawler algorithms are suggested.

Infiltration of Mould from Crawl Space under the Prefabricated Bathroom

The indoor mould concentration depends not only on the outdoor mould source but also on the indoor mould source. The mould source is not only on the interior surface but also in the concealed spaces: a crawl space, a beam space, a wall cavity etc. Most detached houses in Japan have crawl spaces under the first floor. The humidity is high from spring to autumn in crawl spaces. Therefore the concentration of mould spore is very high in most crawl spaces. Prefabricated bathrooms called “bath-units” are installed in most Japanese houses. The authors showed in the previous studies that there are infiltration routes between bath-units and walls that the routes may lead chemical compounds from crawl space to indoor space. In this study, the influence of mould infiltration from crawl space upon indoor mould concentration is investigated using a test house which consists of a lavatory and a bathroom. The structure of the house is wooden post-and-beam. The house is airtight and insulated according to the latest building code for save energy. The mould concentrations were measured in the crawl space and the indoor spaces continuously using a mould multi-sampling system with a pump, valves and impingers. Before the measurements, the indoor mould concentration was made low using an air cleaner. The air flow rates were measured using tracer gases. After the exhaust fan was switched on, the mould concentration increased. The number of infiltrated mould was calculated using air flow rates and mould concentrations. The results showed that mould infiltration ratio may be one of the important indicators of indoor air quality.

爬行真的可有可无吗?——婴幼儿动作发展的国际论证与经验启示

动作发展是指个体在成长过程中逐渐掌握并发展出的各种动作技能。爬行在婴幼儿动作发展中扮演着重要角色,对认知神经系统、肌肉骨骼系统、动作能力和社交能力等方面的成长发育有着积极意义。然而,我国学术界对于动作发展,尤其是爬行的重视程度相对较低,且公众对于爬行在个体成长中的重要性认知不足。以爬行这一婴幼儿时期关键的动作发展里程碑为例,运用文献资料法和逻辑分析法,系统梳理了国际上关于婴儿爬行的相关研究,包括其发展变化、多元作用、影响因素和干预措施等方面的理论研究与实践探索。对实现我国“幼有优育”的婴幼儿健康成长的研究启示主要有:开展大样本的婴儿爬行队列研究;采用婴儿爬行经历作为临床筛查的参考指标;改善婴儿家庭养育的爬行支持环境;完善特殊婴儿的爬行活动干预。

城轨车防爬缓冲装置的可靠性优化研究

为提升防爬缓冲装置的可靠性,对防爬缓冲装置进行了可靠性优化。首先通过试验设计建立了吸能量和初始峰值力的近似模型,经确定性优化得到了pareto前沿的最优解。然后在确定性优化的基础上引入了可靠度约束并进行可靠性优化,得到了符合可靠度要求的最优解。结果表明,相比于确定性优化,可靠性优化的优势更加明显,它在对防爬缓冲装置进行耐撞性优化的同时,也保证了结构的可靠性,为工程实际中防爬缓冲装置的可靠性优化提供了参考。

压电爬行平台高精度步长控制调速方法

压电爬行平台是实现微纳尺度运动控制的重要执行器,其调速精度直接影响定位的准确性.然而,压电爬行平台在开环调速中常采用频率控制调速方法,并未考虑压电致动率相关特征对单步步长的影响,因此导致压电爬行平台的速度公式失准,使运动的定位精度受到损害.为解决此问题,本文提出高精度步长控制调速方法.该方法能够结合速度公式,在定频率下使用电压-单步位移特性对步长精准建模,通过调节切向压电叠堆的电压信号峰峰值控制步长大小,从而忽略率相关特征的影响,满足压电爬行平台调速精度需求.实验证明,在压电爬行平台的倍速控制对比中,高精度步长控制调速方法的控制效果显著优于传统频率控制调速方法.在2.0秒定时长的终点位置处,两组对照实验的开环定位误差率分别从9.642%和17.01%减小至0.282%与0.729%.

昆虫级微型爬行机器人的研究综述

爬行作为动物的一种有节律的运动行为,众多学者对其潜在机理的研究已经持续了一百多年。随着计算机集成技术、材料科学、空气动力学、微纳制造与人工智能技术的不断进步,对仿生爬行机器人的研究正朝着微型化和智能化的方向发展。本文对昆虫级微型爬行机器人的前沿动态发展进行了综合评述,并结合当前发展态势给出了微型爬行机器人未来发展的建设性意见。首先介绍了微型爬行机器人的研究背景和基本概念,对微型爬行机器人的运动机理和稳定性判据进行了简单分析。然后分析了微型爬行机器人的驱动方式并比较了各种微型爬行机器人的性能。最后,从供能、制造和设计3方面对微型爬行机器人的关键技术进行了总结,探讨了微型爬行机器人研究面临的问题,并提出了微型爬行机器人未来的应用前景和发展方向。

复杂地形多功能轻型机器人设计与研究

随着当今自然灾难、野外战争的频繁发生,如何能在野外复杂的地形下搜寻目标和运输补给具有重大意义。然而,自然灾难和野外战争的环境恶劣,搜寻目标及运输补给的过程中往往面临野外地形复杂、搜寻难度大、搜寻成本高等系列问题,从而制约着搜寻作业的顺利进行。对此,提出了一种具有爬行、轮式移动、腿足跨越的复杂地形多功能轻型机器人。对其进行了结构设计;结合其设计模型,对其运动的最大步长、最大倾斜角度、升降范围等性能参数进行了计算分析,对其承载能力进行了应力应变仿真;最后,制作工程样机对其性能进行了验证。结果表明,设计的复杂地形多功能轻型机器人可以实现爬行、轮式移动、腿足跨越3种功能,其跨越障碍的最大倾斜角可以达到53°,其穿越障碍的最大高度可以达到4.1cm。

管桁架焊缝检测机器人夹紧机构瞬态振动特性分析与试验

为保证管桁架焊缝检测机器人夹紧瞬间的稳定性,对机器人夹紧瞬间的振动特性展开研究。根据夹紧机构零部件配合方式构建夹紧机构振动模型,对机器人夹紧瞬间进行仿真,分析夹紧瞬间夹紧机构的响应情况,研究夹紧机构对模型参数的敏感程度。对夹紧机构进行改进,提高弹簧刚度,增加动态吸收器,建立改进后的夹紧机构瞬态振动模型,并在MatLab中进行仿真分析。开展夹紧机构振动测试试验,测量原始与改进后机构的振动情况,对比弹簧支撑振动测试结果与仿真结果。结果表明:弹簧刚度对弹簧压缩量影响最大,弹簧阻尼对调整时间影响最大;机构改进后,调整时间缩短,弹簧压缩率显著降低,稳定性优于原始机构;试验结果与仿真结果的瞬态性能指标误差均小于5%,试验结果与仿真结果具有一致性。

中小企业爬取数据的正当性及规制路径

围绕大型互联网平台企业生态圈生存发展的中小企业的数据利益应受到重视。对于中小企业而言,数据爬取是获取数据资源的重要方式。当前,尚无专门规制中小企业爬取数据行为的法律规范,法律缺位将导致数据爬取纠纷层出不穷,也增加司法裁判的难度。因此,有必要对中小企业爬取数据行为进行正当合理的规制,促进数据的利用、共享,助力数字产业创新。中小企业爬取数据正当性不仅需要从私法权益保护路径论证,还需要从竞争法路径论证。中小企业爬取数据行为应遵循爬取的基本原则,并综合考量爬取目的、对象、方式及爬取造成的损害结果,把数据爬取行为限制在合理边界内。规范数据爬取行为的同时,建立数据合规制度、数据合理使用制度及数据信托制等,有利共同完善数据爬取的法律规制。

MeLAZY1c基因调控木薯株型的初步研究

IGT基因家族参与作物株型的调控,LAZY属于IGT的亚家族。以拟南芥6个LAZY成员氨基酸序列为“种子”在木薯基因组中进行比对,在木薯中共鉴定到8个LAZY基因,其中MeLAZY1c与调控分枝角度的AtLAZY1高度同源。基于此,本研究以MeLAZY1c为研究对象,利用qRT-PCR分析发现MeLAZY1c在茎中转录水平最高,GUS染色显示pMeLAZY1c在维管束中染色较深。在MeLAZY1c启动子中发现8个光响应/调节元件,随后发现黑暗能显著抑制其表达水平。同时对MeLAZY1c进行基因编辑,获得纯合编辑株系19个,炼苗移栽后观测表型,发现melazy1c突变体植株与SC8野生型相比,其主茎呈现匍匐生长,并且弯曲部位茎外皮细胞形态扭曲变形且大小不一致,近地侧1 mm处细胞数目约是远地侧细胞数量的1.5倍,表明MeLAZY1c在木薯直立/匍匐生长建成方面发挥着重要作用。

人体爬行运动信号检测与处理的研究进展

爬行是幼儿粗大运动发育的重要标志,同时也是运动障碍患者重要的康复训练手段,准确评价人体爬行运动状态对于了解幼儿粗大运动发育进程以及运动障碍患者康复疗效等具有重要的临床应用价值。因此,近年来许多研究尝试通过检测分析人体爬行过程中的运动生理信号来实现对爬行状态的量化评价,但目前缺乏针对人体爬行运动信号检测与处理的整理工作,本文对相关研究进行系统综述。首先,从惯性传感器、压力传感器、表面肌电等角度介绍目前面向人体爬行运动信号检测的主流方法;然后,依次介绍针对人体爬行运动信号进行周期分割、运动学分析、动力学分析等内容,其中立足于运动协同理论,详细总结人体爬行运动过程中关节协同运动、肌肉协同收缩方面的研究进展;最后,对当前人体爬行运动分析存在的问题和未来的发展方向进行讨论及展望。

网络爬虫行为版权侵权的行政规制

网络爬虫是一项能够根据指令自动搜索并抓取指定网络信息内容的新兴互联网技术,存在被滥用之风险。作为爬取网络版权数据信息的工具,网络爬虫行为版权侵权现象时有发生。目前,对于网络爬虫行为版权侵权的规制多见于民法与刑法领域,忽视了行政规制。目前存在的网络爬虫行为侵权规制过于依赖司法手段、缺乏针对网络爬虫行为的必要规范以及行政机关针对网络爬虫行为的互联网监管缺失等问题,阻碍了网络爬虫行为版权侵权行政规制的应用与发展。对此,可以从构建网络爬虫行为版权侵权的全覆盖预警系统、完善网络爬虫行为版权规范内容和设置网络爬虫使用者自律管理义务等方面着手,充分利用行政手段遏制网络爬虫行为版权侵权,保护版权权利人的合法权益。

数据爬取不正当竞争认定的反思及路径重构

数据爬取是近些年才成熟的技术,其天然的技术中立性使得爬取行为亦具有竞争中性之属性。数据爬取以互联网为依托,而互联网领域跨界竞争乃为常态,这便对传统竞争关系认定理念造成冲击。同时,数字科技这一新兴领域的商业道德标准模糊,使得正当性认定标准难以统一。司法裁判理念亦未完全革新,涌现出许多类案不同判的现象。基于此,应将“竞争关系”作实质性解读,即只要双方经营者之间的交易机会、竞争优势等存在此强彼弱的关联反应,便可以认定双方存在竞争关系。对于正当性认定,可将多元利益动态衡量作为基础框架,秉持谦抑干预理念,以比例原则作为主要进路,细化商业道德认定标准,分获取、使用两个阶段对行为正当性分别进行评判。只有统一司法认定标准,才能对不正当的数据爬取行为进行精准、有效规制。

基于Halbach阵列的新型吸附结构设计及其优化

为解决目前爬壁机器人永磁式吸附结构难以改变吸附力大小的问题,提出了一种基于Halbach阵列的新型永磁式吸附结构,该结构由方形永磁体和圆柱形永磁体按一定的充磁方向排列组合而成,通过转动圆柱形永磁体改变充磁方向,从而改变吸附力大小.采用ANSYS Maxwell软件研究了吸附结构各参数(永磁体数量、轭铁厚度、气隙大小)对吸附力和单位吸附力的影响,并对以上参数进行优选;以单位吸附力为目标参数,基于粒子群算法对两种永磁体尺寸进行优化,优化前永磁体体积为219823 mm^(3),吸附力为744 N,永磁利用率为0.00352N/mm^(3),优化后永磁体体积为160027.4 mm^(3),吸附力为819.7 N,永磁利用率为0.00510 N/mm^(3).研究结果表明:吸附结构优化后节省了27.2%所占据的空间,增加了15.1%的总体吸附力,提升了45.5%的永磁利用率,优化后吸附结构的吸附性能有了显著提高,可为永磁式吸附结构的设计及优化提供参考.