共查询到20条相似文献,搜索用时 93 毫秒
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针对数控机床几何精度设计过程中整机精度设计指标难于合理确定的问题,提出一种基于待加工试件公差指标反演机床刀具工件间相对位姿误差允许变动范围的方法。该方法首先建立试件单一公差项与机床位姿误差之间的约束关系模型,即为满足试件单一公差要求,机床刀具工件间相对位姿误差需要被控制在何种范围内,然后将所有公差项对应的变动范围求交集即可得到机床位姿误差的允许变动范围,并作为整机精度设计的设计指标,用于机床零部件公差分配。推导了常用公差项对应的位姿误差变动范围的求解方法,并以机床精度检验标准中轮廓加工试件为例,阐述了所提方法的应用过程。 相似文献
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一种基于位姿反馈的工业机器人定位补偿方法 总被引:1,自引:0,他引:1
为了提高工业机器人的绝对定位精度,提出了一种基于末端位姿闭环反馈的机器人精度补偿方法。该方法通过激光跟踪仪测量实时跟踪机器人末端靶标点的位置来监测机器人末端的位姿,并通过对靶标点的实际位置和理论位置进行匹配获得机器人末端的位姿偏差。工业机器人系统与激光跟踪测量系统通过局域网进行数据通信,并根据位姿偏差数据对机器人末端的位姿进行修正。最后通过实验对基于末端位姿闭环反馈的机器人精度补偿方法进行验证,实验表明,经过位姿闭环反馈补偿后机器人末端位置误差最大幅度可以降低到0.05mm,姿态误差最大幅度可以降低到0.012°。 相似文献
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一种含平行四边形支链的3自由度并联机构姿态精度综合与装配工艺设计 总被引:2,自引:0,他引:2
以含平行四边形支链的3平动自由度并联机构主模块为对象,通过误差建模揭示出影响这种机构末端姿态精度因素。利用灵敏度分析结果,将精度综合归结为一类有约束线性规划问题,并据此提出两种可以有效抑制末端姿态误差的装配工艺方案。 相似文献
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Machine tools used for batch and mass production are generally equipped with the Geneva Mechanism for indexing. One of the factors affecting the machining accuracy in these machine tools is the positional accuracy of the tools with respect to the work which, in turn, is affected by the indexing accuracy of the indexing mechanism. This paper discusses the effect of manufacturing tolerances on indexing accuracy. It is observed that indexing accuracy is different for constrained and unconstrained designs corresponding to the same value of tolerance. Results regarding indexing accuracy for different values of tolerances in constrained designs are recorded and suggest that, in the case of constrained designs, careful allocation of tolerances on design parameters is needed. The method of tolerance allocation suggested by Choubey and Atluri8 is followed. Synthesis of a six-slot Geneva Mechanism incorporating manufacturing tolerances and following stochastic non-linear programming and the exterior penalty function method is carried out to study these effects. Practical implications of the effects of manufacturing tolerances on indexing accuracy and synthesis of Geneva drives are discussed, giving suitable examples 相似文献
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基于混合部件模型的人体姿态估计方法忽视了人体结构的对称位姿约束关系,从而导致对称部件容易被重复检测、人体姿态估计准确率较低,为此,提出一种基于位姿约束与轨迹寻优的姿态估计新方法。首先估计人体单部件和对称部件在单帧图像中的多个合理位置,利用对称部件之间的位姿约束关系构建标识部件。然后根据单部件和标识部件各自的目标优化函数,通过动态规划算法反复迭代获得初始轨迹候选集,再结合轨迹的全局特征剔除检测得分较低的运动轨迹。最后引入树形合约模型,联系时空上下文信息,准确求解出视频序列光滑且兼容的最优轨迹。在N-best、Outdoor Pose和Scene数据集中的实验结果表明,对于存在背景复杂、运动模糊、部件遮挡等问题的视频序列中,该方法平均姿态估计准确率达87%以上,有效减少了对称部件的误判,提高了视频中人体姿态估计的准确率。 相似文献
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行星滚柱丝杠(PRSM)公差主动设计对提高其传动性能与加工可行性有着至关重要的作用。建立了综合考虑丝杠、滚柱、螺母的螺纹同轴度误差、螺距误差与中径误差的PRSM行程误差及轴向间隙模型,计算得到各误差因素敏感性指数;基于三角模糊数的专家评判层次分析法,计算各误差因素加工权重,初步分配PRSM行程精度各误差项公差;基于序列二次规划算法对轴向间隙各误差项公差进行优化;以标准型PRSM为例,验证了该方法的有效性。结果表明:针对行程精度与轴向间隙各误差项进行公差优化的方法,不仅极好地平衡了行程精度与轴向间隙,且增加了关键公差带宽度,提高了零件加工可行性,算例表明,优化后完整周期内轴向间隙最小值由-25μm变为0,避免螺纹干涉发生;优化后V300行程变动量基本不变,公差带宽度平均增加65%,保证PRSM 5级精度指标的同时提高了关键零件加工可行性,降低了加工成本,可为PRSM公差主动设计理论提供参考。 相似文献
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针对平面四杆连杆机构的函数再现问题,分析了随机性的干扰因素对机构运动精度的影响,建立了模糊稳健优化设计数学建模.采用支持向量回归机对模糊概率等非线性函数进行仿真计算,提高了模糊稳健优化设计的求解效率、降低了机时消耗.给出了新方法的具体算法步骤,该方法能使机构运动精度和各尺寸的制造公差得到合理匹配,具有工程实用价值. 相似文献
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运用并行公差优化设计方法对精密卧式加工中心线性轴进行公差分配.在保证机床现有精度条件下,综合分析机床各线性轴制造误差的敏感度和加工成本,优化了给定结构机床线性轴导轨选型和导轨基面工序公差的精度设计,节约了机床制造成本. 相似文献
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Bernard Anselmetti 《The International Journal of Advanced Manufacturing Technology》2010,48(9-12):1221-1237
A tolerance synthesis provides the distribution of tolerances on the functional specifications of parts for a mechanism, with the objective of satisfying a set of functional requirements. This approach involves adjusting the nominal dimensions of parts. The present article offers a six-step solution within an Excel solver environment. The designer is able to control the optimization process using a dashboard. The initial steps detect conflicting requirements and suggest compromises, while the subsequent steps optimize the nominal part dimensions in order to maximize mechanism quality with minimum tolerance. The final steps then seek to maximize tolerances with the aim of minimizing costs. The proposed method can also manage specifications with both maximum and minimum material requirements. 相似文献
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Marie Royer Bernard Anselmetti 《The International Journal of Advanced Manufacturing Technology》2016,84(9-12):2151-2165
The safety and performance requirements for mechanisms are such that the necessary accuracy of part geometry is difficult to reach using classical manufacturing processes. This paper proposes a manufacturing tolerance stack-up method based on the analysis line method. This technique enables both the analysis and the synthesis of ISO manufacturing specifications through a new approach which relies on production specifications, adjustment specifications, and their analysis to stack up the 3D resultant. The originality of the method resides in the 3D calculation for location requirements, which takes into account angular effects and probing operations on numerical-control machine-tools in order to define a local work coordinate system (WCS). For achieving tolerance analysis, deviations are modeled using small-displacement torsor. This tolerance analysis method enables one to determine explicit three-dimensional linear relations between manufacturing tolerances and functional requirements. These relations can be used as constraints for tolerance optimization. 相似文献