一种基于局部感知的多机器人编队控制方法

针对未知环境下多机器人难以实现灵活、稳定的编队控制的情况,在分析领队-跟随法、基于行为方法以及虚拟结构法的编队控制方法基础上,提出了一种模拟人类社会中方队形成与变化的思想,将其应用在多机器人的编队中,进行多机器人的编队控制.机器人存储不同编队队形的相对位置信息,通过领航者发布队形控制信息,跟随者查找并匹配预先存储的队形...     

基于通信的多移动机器人编队控制系统

论述了一类通用的经过通信信道进行协调的多移动机器人编队控制系统.在分别获取自身位姿信息的前提下,各个机器人通过通信信道交换和共享同组成员的位姿信息,然后通过计算得到各机器人之间的相对位姿,进而完成编队协调任务.利用此技术,可实现一种不受环境限制的多机器人编队,其特点在于编队的完成主要依赖于通信系统,不论编队中各机器人是否能够彼此感知,编队都能进行,从而提高了多机器人编队对环境的适应性.采用闭环l-ψ编队控制算法验证此设计方法的有效性,在三台移动机器人上进行了实验,实验结果证明了该方案的可行性.     

未知环境中基于观察者的多机器人编队控制方法

结合领导-跟随法和VFH+ 避障法,提出一种基于观察者的多机器人编队控制方法,并利用Player/Stage机器人仿真平台,对编队控制方法进行了仿真实验.结果表明,编队控制方法可有效地将一组移动机器人以一定队形无碰地到达指定目的地.基于Player/Stage机器人仿真平台的特性,编队控制方法完全可以用于实际机器人上.     

基于仿生鱼群优化方法的非完整机器人队形控制(英文)

利用人工鱼群优化(AFSO)方法研究了多机器人的队形控制问题。机器人编队可视为寻迹问题,而编队寻迹是不断减小机器人与其期望编队位置之间的平移和角度误差的优化过程。每一个机器人的控制指令可看做是人工鱼群,通过一系列的控制实现期望队形。队形控制策略中包含机器人间的冲突规避行为。利用Matlab中的多机器人仿真器MRsim工具进行了仿真,结果表明,提出的方法具有很高的有效性和效率,适用于各种形式的队形,可以被广泛应用在没有精确系统模型的无线传感器网络中。     

基于仿生鱼群优化方法的机器人队形控制

本文利用人工鱼群优化（AFSO）方法研究了多机器人的队形控制问题。机器人编队可视为寻迹问题,而编队寻迹是不断减小机器人与其期望编队位置之间的平移和角度误差的优化过程。每一个机器人的控制指令可看做是人工鱼群,通过一系列的控制实现期望队形。队形控制策略中包含机器人间的冲突规避行为。本文利用Matlab中的多机器人仿真器MRsim工具进行了仿真,结果表明本文提出的方法具有很高的有效性和效率,适用于各种形式的队形,可以被广泛应用在没有精确系统模型的无线传感器网络中。     

基于干扰观测器的多移动机器人编队鲁棒控制

针对多移动机器人存在模型参数不确定性和外部扰动的编队控制问题,提出了一种多移动机器人编队的鲁棒控制方法。在运动学层面依据领航机器人和跟随机器人位姿的偏差,建立领航机器人和跟随机器人的编队误差动态模型,在此基础上为跟随机器人设计镇定编队误差的辅助速度控制器。以辅助速度控制器的输出作为跟随机器人动力学模型的速度给定信号,并在动力学层面设计基于干扰观测器的自适应滑模控制算法,从而改善普通滑模控制中抖振突出的问题,保证编队控制的稳定性和鲁棒性。对编队控制系统进行仿真验证,结果表明了所提控制方法的有效性。     

基于领航跟随法和星系动力学的多机器人编队控制

针对机器人常规编队控制方法编队精度低、机器人易掉队,且当队形进行大角度变换时跟随者不能快速适应的问题,提出了一种基于领航跟随和星系动力学(LF-GD)机器人编队控制方法.该方法结合了领航跟随法控制简单、编队快速和星系动力学法编队稳定和动态均衡的优点.实现了机器人快速编队和动态避障的性能要求,避免了队形大角度变换时机器人相互之间的碰撞和掉队问题,提高了整个编队系统的智能性和环境适应性.通过仿真验证了该方法的可行性和有效性.     

多智能体编队避障算法研究

利用势函数方法,研究了多智能体在障碍物环境下的追击编队控制.为解决单个智能体在势场中存在局部极小点与动态性能不好问题,引入速度势场建立新的势场函数.并研究了多智能体在不同环境下的编队控制,其中包括无障碍物环境,静态障碍物环境,以及静态障碍物和动态障碍物并存的复杂环境.通过选择与目标,障碍物和编队队形相关的势场函数,提出一种新的分布式编队避障控制算法.仿真结果表明所提算法能有效地解决多智能体编队避障问题.     

基于竞标机制的多移动机器人实时编队控制

研究了整体时间最优的多移动机器人实时编队控制问题。由于在多机器人编队围捕等一些任务中,存在任务时间或通信范围有限等约束,提出了基于竞标机制的时间最优控制策略。针对编队过程中机器人可能发生故障等问题,在实时编队控制策略中设置了监督机制,以保证任意时刻编队队形的完整。设计了与竞标和监督机制相适应的机器人编队及运动行为,使得移动机器人的运动时间最少。通过编队形成及编队改变等一系列实时编队仿真实验,结果表明:本文提出的编队控制策略灵活可行,且能满足编队控制中实时性的要求。     

基于相邻矩阵的多机器人编队容错控制

针对基于leader-follower模式的多机器人编队运动中可能出现的机械故障和网络故障,提出了一种基于相邻矩阵的容错控制方法,利用相邻矩阵表示编队中多机器人的相互位置关系,一旦在编队运动过程中出现故障,则利用调整队形搜索算法找到需要进行队形调整的机器人编号,根据相邻矩阵更新算法,这些编号所代表的机器人的相邻关系在相邻矩阵中得以调整,新的理想编队所对应的相邻矩阵产生,编队队形就可以依赖相邻矩阵重新得以恢复。从而实现多机器人编队的容错控制,仿真实验证明了该方案的有效性和可行性。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.