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1.
基于遗传算法的两足步行机器人步态优化   总被引:4,自引:0,他引:4  
将具有24 个自由度的机器人JFHR简化为7 连杆机构,建立了描述机器人姿态的位置向量.用三次多项式拟合机器人髋关节和踝关节的位置轨迹,并通过动力学模型建立能量消耗表达式,得到能量最优的步态,即多项式系数的获得就可以表示为一个多变量最小值的优化问题,最后应用遗传算法(Genetic Algorithm , GA)获得最优解.在GA设计中,将每一个需要优化的参数用10位二进制数表示,种群中染色体的个数为50,演化的代数固定为100,杂交率和变异率分别定为0.8和0.04.对平地步行和斜坡步行进行了仿真.  相似文献   

2.
以PID控制为基础,提出了一种适应于两足步行机器人计算机控制系统的设计方法,并对一些相关问题进行了讨论.本文提出的这种设计方法已被成功地应用于NAIWR-1两足步行机器人.实践证明,它对控制两足步行机器人的稳定行走是有效和可行的.  相似文献   

3.
模糊神经网络在四足步行机器人控制中的应用   总被引:1,自引:1,他引:1  
将神经网络和模糊控制理论应用于四足步行机器人的控制中,并在实验基础上选取样本,设计了针对四足步行机器人的模糊神经网络控制系统.  相似文献   

4.
本文提出了两种智能步行轮的腿机构,对机构的运动特性进行研究,详细讨论了在各种道路条件下实现智能步行轮预定运动规迹的控制方式和控制规律.以及机构设计参数对控制规律的影响.  相似文献   

5.
四足步行机器人中一种新型腿结构缓冲特性   总被引:6,自引:0,他引:6  
四足步行机器人在高速步行时,地面对其产生了很大的冲击,引入弹性步行机构是减少冲击的关键.将一种新型弹性步行机构应用于四足步行机器人中,分析其工作原理,并研究其控制电路.进而以Pacing步态为例,对弹性步行机构的缓冲和储能功能进行了理论探讨和实验分析,并在对刚性腿和弹性腿对比研究的基础上,指出将弹性步行机构应用于四足步行机器人具有独特的优越性.  相似文献   

6.
推导了四足步行机器人的动力学模型,在此基础上利用平方规划方法研究开发四足步行机器人脚力分配的新算法.这种方法既考虑电机模型,分析了四足步行机器人的关节驱动约束条件,又结合摩擦等约束分析及转换,建立了机器人多约束方程,利用平方规划提高解的质量,并缩减解的规模.最后通过实例验证了该算法的优越性。  相似文献   

7.
基于仿生研究的步行机缓冲型腿机构设计   总被引:4,自引:0,他引:4  
基于仿生研究成果设计出一种含有弹性元件的缓冲型腿机构,分析其工作原理和参数选择原则,具有结构简单、性能可靠的优点.对比分析了几种设计方案的刚度随着压缩量的变化情况.这种具有非线性刚度变化的腿机构初步解决丁机器人在动态行走时的冲击以及由此产生的振动,使机器人在高速行走时得到缓冲并达到节能,提高了机器人的能效,从而得到一种适合于动态步行机器人的缓冲型腿机构.这种腿机构不仅适用于实现动态行走的四足步行机器人,也可适用于高速步行下的多足机器人。  相似文献   

8.
两足步行机器人动态步行规划及仿真   总被引:1,自引:0,他引:1  
根据双足步行机器人动态步行过程中必须满足的动态关系式,提出了动步态规划的两步规划法,从而既满足了机器人步行过程中的基本要求,又保证了系统能够实现动态协调运动。在此基础上,对无冲击步行机器人动态步行过程进行了规划和仿真。结果表明,两步规划法满足了动态步行的要求。  相似文献   

9.
在分析传统多关节腿式机器人动作协调问题的基础上,重点介绍全方位双三足步行机器人DTWM的设计,包括新型步行原理、步行机构及控制系统。DTWM依靠车体变形及被动适应地面的方法产生步行,在很大程度上简化了步行过程中复杂的动作协调控制问题;在控制系统中基本步行指令集的设计和应用,使得步行运动控制方便可靠。因此,DTWM的性能特点显示出它具有良好的应用前景。  相似文献   

10.
根据双足步行机器人动态步行过程中必须满足的动态关系式,提出了动步态规划的两步规划法,从而既满足了机器人步行过程中的基本要求,又保证了系统能够实现动态协调运动.在此基础上,对无冲击步行机器人动态步行过程进行了规划和仿真.结果表明,两步规划法满足了动态步行的要求.  相似文献   

11.
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.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
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.  相似文献   

13.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

14.
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.  相似文献   

15.
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。  相似文献   

16.
王慧 《科技信息》2008,(10):240-240
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.  相似文献   

17.
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.  相似文献   

18.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

19.
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.  相似文献   

20.
1 Rise of studies on climate change's effects on biodiversity
Until the 1980s, climate change and biodiversity were studied as two independent disciplines for more than a century. In 1992, the Ecological Society of America's annual report named climate change, biodiversity, and the sustainable ecological system as the three major global environmental issues of the twenty-first century [1].  相似文献   

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