共查询到20条相似文献,搜索用时 109 毫秒
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对平面二自由度五杆机构的位姿形式及位置逆解进行分析之后,提出了用二自由度辅助机构进行全铰链五杆轨迹机构综合的方法。该方法先将平面二自由度全链五杆机构看成由两个开链二杆机构组成的机构。然后按照给定要实现的轨迹,用二自由度辅助机构分别综合出两个开链二杆机构。最后再将综合出的两个开链二杆机构组合成全链五杆机构。按照此种方法综合出的全铰链五杆机构可精确地实现给定的轨迹,配以合适的驱动方式可进行异形边界及系列边界的加工,本文的研究为特殊类型边界的加工提供了手段。 相似文献
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一种新型3自由度并联机构的奇异性分析 总被引:4,自引:0,他引:4
研究一种新型空间3自由度并联机构(HANA)的奇异性。该机构由定平台、动平台和三个联接支链组成,其动平台相对于定平台具有2个移动和1个转动自由度。其结构主要特点是只采用了单自由度的运动副。构型优势主要是转动自由度灵活度高。详细分析了该机构的三类奇异形位,为以后关于该机构的工作空间和转动能力分析以及控制提供基础,特别是基于合理设计的工作空间内无奇异特性将保证该机构拥有很高的转动能力。该机构不仅可以应用在并联机床的设计中,还可以广泛地应用在工业机器人、飞行模拟器和微型机器人等领域。 相似文献
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3-6Stewart平台安全机构设计 总被引:1,自引:0,他引:1
提出了一种通过优化杆长的最大伸长比来进行Stewart平台安全机构设计的方法。首先用 Stewart平台上平面顶点轨迹圆的集合定义了顶点空间 ,并通过设计伸长比 ,生成不同的顶点空间 ;进而在考虑上平面几何约束的条件下建立约束方程 ,在顶点空间内 ,将满足约束条件的机构的设计问题转化为三角形方程组解的存在性问题 ;最后利用 Strum定理来确保在任一组顶点轨迹圆上都存在满足约束条件的实解。仿真实验表明 ,应用该方法设计出的 Stewart平台不但能够满足机构的约束 ,而且具有最大的工作空间。 相似文献
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曲柄群驱动机构是一种特殊的传动机构,根据经典机构学的理论,它是一个超静定机构,文中将它视为一种特殊的并联机构,运用基于螺旋理论的自由度分析方法,对存在p个曲柄的该机构的自由度进行了分析,从约束螺旋的角度深入分析了其被约束的自由度,结果表明其自由度为1,破解了它的超静定问题,为该机构的应用提供了理论依据。 相似文献
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为揭示任意个球面剪叉单元构成的球面可展机构的运动特性,研究这类机构的自由度特性和运动分析方法。基于螺旋理论分析球面剪叉单元及其串联运动链、多支链构成的球面可展机构的自由度特性,得出由球面剪叉单元构成的球面剪叉可展机构的自由度特性,据此构造出任意个球面剪叉单元和任意个支链构成的自由度为1的球面可展机构。基于球面几何理论,对两个球面剪叉单元串联的球面可展机构进行运动分析,并对任意m个球面剪叉单元串联的球面可展机构进行运动分析,在此基础上分析n个支链的球面剪叉可展机构的运动特性。建立球面剪叉可展机构这类机构通用的运动分析方法,并给出运动分析的数字实例,证明了该方法的有效性。编制能满足任意个球面剪叉单元构成的球面可展机构的运动分析软件,实现了对这类机构运动的自动分析计算,具有工程应用的实际意义。 相似文献
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Wang Wen Wu Shixiong Chen Zichen Department of Mechanical Engineering Zhejiang University Hangzhou China 《机械工程学报(英文版)》2004,17(2):189-192
NC code or STL file can be generated directly from measuring data in a fas re-verse-engineering mode. Compressing the massive data from laser scanner is the key of the new mode.An adaptive compression method based on triangulated-surfaces model is put forwar. Normal-vectoranges between triangles are computed to find prime vertices for removal. Ring data structure isadopted to save massive data effectively. It allows the efficient retrieval of all neighboring vertices andtriangles of a given vertices. To avoid long and thin triangles, a new re-triangulation approach based onnormalized minimum-vertex-distance is proposed, in which the vertex distance and interior angle oftriangle are considered. Results indicate that the compression method has high efficiency and can getreliable precision. The method can be applied in fast reverse engineering to acquire an opimal subsetof the original massive data. 相似文献
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基于径向基函数的多种类型孔洞修补算法研究 总被引:3,自引:0,他引:3
利用径向基函数对散乱数据点进行曲面重建受到越来越多学者的关注,并被应用于解决网格模型中的孔洞修补问题。本文在实现径向基函数对简单孔洞进行修补的基础上,进一步研究了对多种类型孔洞的修补问题,提出了统一的修补算法:首先利用填充算法对孔洞进行填充,然后使用径向基函数建立孔洞区域的隐式曲面,最后将新增加的三角片顶点调整到建立的隐式曲面上,并给出了修补结果的优化处理。实例证明,该算法适用性好,对不同类型孔洞的修补效果理想。 相似文献
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Loop细分曲面的自适应等距面生成算法与实现 总被引:3,自引:0,他引:3
提出一种精确快速生成有边界等距 L oop细分曲面的新算法 ,其核心思想是 :从控制网格顶点在 L oop细分曲面上的位置 ,按照给定的等距值 ,沿其法矢正 (反 )向等距 ,通过解线性方程组求出等距后的控制网格 ,然后检测等距误差 ,对部分超过给定等距精度的控制网格进行局部自适应细分 ,重新生成等距面并检测误差 ,直至整个细分等距曲面满足精度要求 ,所生成的等距细分曲面除局部 C1 外其余 C2 连续。实例表明 :本算法高效稳定 ,生成的等距细分曲面已完全满足实际工程需要。 相似文献
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WU Shixiong WANG Chengyong School of Mechanical Electrical Engineering Guangdong University of Technology Guangzhou China CHEN Zichen College of Mechanical Energy Engineering Zhejiang University Hangzhou China 《机械工程学报(英文版)》2006,(1)
A region-growing method for reconstructing triangulated surfaces from massive unorganized points is presented. To save memory space, a ring data-structure is adopted to build connections between points and triangulated surfaces. The data-structure allows the efficient retrieval of all neighboring vertices and triangles of a given vertice. To narrow the search range of adjacent points and avoid mangle intersection, an influence area is defined for each active-edge. In the region-growing process of triangulated surfaces, a minimum-edge-angle-product algorithm is put forward to select an appropriate point to form a new triangle for an active edge. Results indicate that the presented method has high efficiency and needs less memory space, optimized triangulated surfaces with reliable topological quality can be obtained after triangulation. 相似文献
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Jong-Geun Kwak Sang C. Park Minho Chang 《The International Journal of Advanced Manufacturing Technology》2010,50(1-4):409-418
A virtual factory is a very useful model for analyzing complex manufacturing systems that cannot be described by analytical or mathematical models. One of the main obstacles in the simulation of a virtual factory comes from the huge size of the geometric data involved. This paper proposes an efficient method for reducing that data volume through introducing a simplification method for virtual factories that consist of prismatic solid models containing complex internal features. The proposed method allows a determination of whether the faces of a virtual factory represent internal features (invisible), which are unnecessary to the simulation and may therefore be eliminated. The proposed approach uses a graphics board optimized to render a given scene and reverses the process; after drawing a scene, we try to identify the entities that are visible. The proposed algorithm splits the given triangles into visible groups, and for each visible group, we can then draw the mesh on a pixel map from the corresponding viewing direction. By querying the colors that appear on the pixel map, it is possible to determine the visible triangles. When the visible triangles are known, it is possible to remove the internal features by removing those invisible triangles from the triangular mesh. 相似文献
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任意曲面离散求交的投影算法及其实现 总被引:1,自引:0,他引:1
提出一种任意曲面离散求交的投影算法。曲面首先被离散为一系列三角形平面子面片 ,然后将这些平面三角形面元分别投影到正投影面和水平投影面上 ,再将得到的两个投影映射到二维空间。在二维空间 ,求出两相交三角形的交线段 ,其集合就是两曲面交线的逼近。在详细描述算法原理后 ,给出了算法的实现步骤 相似文献
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Isomorphism detection is fundamental to the synthesis and innovative design of kinematic chains(KCs).The detec-tion can be performed accurately by using the similarity of KCs.However,there are very few works on isomorphism detection based on the properties of similar vertices.In this paper,an ameliorated multi-order adjacent vertex assign-ment sequence(AMAVS)method is proposed to seek out similar vertices and identify the isomorphism of the planar KCs.First,the specific definition of AMAVS is described.Through the calculation of the AMAVS,the adjacent vertex value sequence reflecting the uniqueness of the topology features is established.Based on the value sequence,all possible similar vertices,corresponding relations,and isomorphism discrimination can be realized.By checking the topological graph of KCs with a different number of links,the effectiveness and efficiency of the proposed method are verified.Finally,the method is employed to implement the similar vertices and isomorphism detection of all the 9-link 2-DOF(degree of freedom)planar KCs. 相似文献