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增大工作空间和提高灵巧度是并联机床设计的一项重要任务。依据运动学反解,采用三维搜索的方法得到了带约束条件的交叉杆并联机床的工作空间;利用自然坐标法推导了该机床的新型雅可比矩阵;基于工作空间和新型雅可比矩阵获得了交叉杆并联机床的灵巧度分布。在此基础上分析了机床各结构参数对工作空间和全域灵巧度指数的影响规律,然后用最小二乘法进行曲线拟合并以工作空间指数和全域灵巧度指数为优化目标对该机床进行优化,与优化前相比,两项指标分别增大了0.40倍和0.26倍,达到了机构优化的目的。 相似文献
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新型6-SPS并联机床局部承载能力分析 总被引:8,自引:1,他引:7
应用并联机器人机构学理论 ,定义了一种新型 6 SPS并联机床处于初始装配位姿时的承载能力性能指标 ,并分析其承载能力性能指标与结构参数关系 ,为设计和使用该结构方案的并联机床提供理论依据。 相似文献
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以6-PSS并联机床为例,从单一支路的运动分析出发,利用并联机床的结构约束条件,得到并联机床显格式的位置反解方程以及工作空间到输入空间的速度和加速度映射矩阵,最后给出衡量并联机床运动精度的重要指标及其计算式。 相似文献
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6-PSS并联运动机床的奇异性分析是6-PSS并联运动机床其它分析的基础,也是空间机构学分析的一个难点。本文首先解释了并联运动机床奇异性特征,通过建立6-PSS并联运动机床结构数学模型,实现了参数化设计。利用螺旋理论空间分析的优势,建立了6-PSS并联运动机床的Plücker坐标,方便地给出机床受力Jacobian矩阵,同时利用Matlab强大数学计算功能,精确的分析出并联机床的奇异性空间,降低了并联运动机床奇异分析的复杂性。 相似文献
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铰链间隙对6自由度并联机床刀具位姿的影响分析 总被引:1,自引:0,他引:1
为了评价6自由度交叉杆型并联机床中铰链间隙对刀具空间位置与姿态(简称位姿)的影响,提出了一种"分解、求交"方法,确定铰链间隙引起刀具平台位姿的可达空间,进而分析铰链间隙对刀具位姿的影响。基于旋量理论,采用指数坐标法推导了该机床各支链的正向运动学指数式解析表达式,并分别求取单支链单独约束下铰链间隙引起刀具平台的可达空间。对6个空间进行求交处理,获得6支链同时约束下的可达空间,即为间隙引起的误差空间。实验结果证明了该"分解、求交"方法的正确性和有效性。 相似文献
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Aspheric optics has been widely employed in some high-tech industries for its superiority. In order to achieve the ultra-precision machining of these aspheric surfaces, the large optical ultra-precision grinding machine becomes crucial because it determines the efficiency of the whole process. As the key functional unit in ultra-precision machine tool, the hydrostatic guideways are commonly adopted for the excellent performance. However, the motion errors of hydrostatic guideways have a direct influence on the accuracy of the machined workpiece, and some analysis approaches have been reported correspondingly. Although the existed analysis models do work, their imperfections also can be easily captured. Accordingly, a novel analysis model with less imperfection is deserved to be developed. In this paper, the kinematic theory is utilized to establish the quasi-static analysis model for motion errors in closed hydrostatic guideways. Through the large ultra-precision grinding machine designed by our research group, the consistently good agreement between the predicted results and the measured experimental data are obtained. Furthermore, it is found that the motion accuracy is more sensitive to the profile error of the guide rail bearing the external load rather than that of the other guide rail in the closed hydrostatic guideway. The presented research is supposed to be valuable to the peer designers. 相似文献
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Guilian Wang 《Machining Science and Technology》2013,17(1):106-121
In this paper, a serial-parallel hybrid special polishing machine tool based on the elastic polishing theory is developed, which is used for polishing mould surface by using bound abrasives. This machine tool mostly consists of parallel mechanism of three-dimensional moving platform, series rotational mechanism of two degrees of freedom and elastic polishing tool device. The parallel mechanism controls the spatial position of the polishing tool. The series mechanism controls the pose of the polishing tool. The elastic polishing tool system can realize active control by a pneumatic servo system and passive conformity by a spring. The main process parameters that have influence on surface roughness and polishing efficiency are tool speed, feed rate, force, pose angle and polishing number of times. Optimal combination of process parameters is presented by the Taguchi and grey relational analysis, which provide a choice of parameters as a basis for free-form surface polishing in practice. 相似文献
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基于边界元法研究混联数控机床整机结构动态特性的解析和建模方法。首先采用粱单元、集中质量单元、弹簧单元及结合部单元建立混联机床整机结构动力学模型,基于边界元方法建立各单元的动力学方程式,通过单元合成方法推导出混联数控机床整机结构动力学方程,用频率扫描法得到整机结构的固有频率。基于所建立混联机床结构动态特性解析方法,开发相应的整机动态特性解析软件,实验证明,所建立混联机床整机动态特性解析方法及开发的软件是可靠的,不仅可以为混联数控机床加工过程中回避薄弱位姿状态提供依据,而且可以为混联数控机床的结构设计提供理论依据,对提高混联数控机床的设计水平具有重要意义。 相似文献
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基于凯恩方程的新型并联机床动力学研究 总被引:10,自引:2,他引:8
新型并联机床是空间多环机构在机床领域的创造性应用,本文以凯恩方程为基础建立了该机床的封闭形式的动力学方程,该方程不使用动力学函数且不需求导运算,因而便于计算机实现,为对并联机床进行动态分析与设计提供了基础。 相似文献
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新型并联机床的固有特性研究 总被引:5,自引:0,他引:5
新型并联机是空间多环机构在数控机床不上的应用,本文建立了该机庆的弹性动力学有限元模型,并确定了机床的结构参数种典型的加工轨迹,经过有限元实例计算得到了机床一阶有频率变化曲线,通过对计算结果的分析得出机床固有频率随机床结构参数和刀头姿态变化的规律。本文的研究对在机床设计阶段提高机床的动力学性能具有重要意义。 相似文献
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Lu Yi 《The International Journal of Advanced Manufacturing Technology》2005,26(9-10):1018-1025
A novel computer-aided geometric approach for machining a 3D free surface by adopting a 3-UPU spatial parallel machine tool is proposed. Based on the geometry constraint and dimension-driving technique, first, a spatial 3-UPU parallel simulation mechanism is created. Next, a 3D free surface and a guiding plane of tool path are constituted. Finally, the 3-UPU spatial parallel simulation mechanism, the 3D free surface, and the guiding plane of tool path are combined together, and a novel spatial parallel 3-UPU simulation machine tool is created for machining a 3D free surface. In the light of two specified tool paths, the extensions of three driving limbs and the position of the moving platform are solved dynamically by adopting the dimension-driving technique. The results of computer simulation prove that the computer-aided geometric approach is not only fairly quick and straightforward in developing or designing, but is also advantageous from the viewpoint of accuracy and repeatability . 相似文献