共查询到18条相似文献,搜索用时 46 毫秒
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在加工过程中,机床会因热变形而产生误差,这将严重影响加工精度。减少加工过程的热误差是提高加工精度的有效途径,而确定关键温度测点不仅能提高计算效率,还可避免温度数据间复共线性问题,提高热误差模型的预测精度。提出基于改进模糊聚类和最大信息系数(MIC)的温度测点选择方法,通过改进模糊聚类对温度测点进行分类;根据MIC方法选择每类温度数据中的关键温度测点;使用BP神经网络对热误差进行建模。结果表明:与传统温度测点选择方法相比,利用所提方法改进的热误差模型精度更高。 相似文献
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机床主轴的模糊优化设计 总被引:1,自引:0,他引:1
机床主轴在传动过程中,具有速度波动,为减少速度波动引起的动载荷影响,设计时要在传递转矩一定的情况下,使质量最小,本文讨论了主轴设计过程中的模糊因素,建立了以截面积最小的模糊优化设计模型,运用模糊理论和方法获得最优解。 相似文献
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根据灰色聚类综合评价的原理和方法,对影响夹具公差选择的多种因素进行了数据处理,建立了夹具公差选择的灰色聚类综合评价模型,为定量确定夹具的公差提供了有效的方法。 相似文献
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运用灰色系统的理论及方法,将疲劳应力与寿命的相互制约关系看成一个灰色系统,将疲劳试验的应力水平均匀分成数级,并找出与之对应的安全寿命的白化值。通过对安全寿命值数列的一次累加,生成一个光滑离散函数。据此建立灰色系统模型,并求解灰色系统的微分方程 。通过残差模型的修正,提高模型精度,再运用灰色系统模型的还原模型,可计算出任一应力水平下的安全寿命值。为机床主轴的安全寿命计算提供了新的途径,具有较大的推广应用价值。 相似文献
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将许用挠度看作模糊变量,将载荷、材料参数、几何尺寸等不确定因素视为随机变量,提出了考虑模糊失效准则的机床主轴刚度靠性分析模型。给出了机床主轴模糊失效的几何意义,推导了其隶属度函数。利用Gauss-Hermite积分,建立了机床主轴模糊可靠性的数值计算方法。数值算例表明,该方法不仅有效地减少了计算量,精度高,而且与实际情况更接近,计算结果更为保守。 相似文献
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在设计机床的主传动非常规变速系统时,首先利用传统优化设计方法求出理想解和多个合理解,然后再把其作为一个灰色系统,利用灰色系统理论中的灰色聚类方法,对多个合理解按满意程度进行排列,其结果可为普通机床的设计、开发提供更趋于实际的理论依据.文中介绍利用灰色聚类方法开发金属切削机床直流电机无极变速的主传动非常规变速系统优化设计的总体结构、功能和方法.本系统具有界面美观、操作方便、易于理解的特点. 相似文献
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热误差作为制约数控机床加工精度的关键因素,在重型数控机床上表现得尤为明显。以重型落地镗铣床为例,根据热误差测量试验数据,分析重型数控机床温度场特性,并基于兼顾相关系数和欧式距离的系统聚类准则,对温度测点系统进行优化,以减小温度测点间共线性。通过优化温度测点,采用多元线性回归分析,建立重型数控机床热误差预测模型。由现场试验可知,建立的热误差预测模型可将均方根误差控制在10μm以内,有效地提高了热误差预测精度。 相似文献
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针对数控机床主轴的控制问题,采用综合鲁棒控制器实现数控机床主轴的有效控制,并对控制效果进行仿真验证。构造数控机床主轴系统模型简图,建立了考虑切削力的数控机床主轴的完整动力学模型。基于H_∞控制策略开发针对机床主轴的综合鲁棒控制器。采用MATLAB软件对数控机床主轴进行仿真,并与传统PID控制器的仿真结果进行对比和分析。结果显示:采用综合鲁棒控制器控制的数控机床主轴转速超调量小,能快速消除波动;所需控制电压范围减少了约50%;即使受到较大随机干扰,主轴系统也能够快速消除干扰,处于受控状态且稳定。采用综合鲁棒控制器可以提高机床主轴的动态稳定性以及抗干扰能力。 相似文献
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Milling machine spindle analysis using FEM and non-contact spindle excitation and response measurement 总被引:3,自引:1,他引:3
Matti Rantatalo Jan-Olov Aidanp Bo Gransson Peter Norman 《International Journal of Machine Tools and Manufacture》2007,47(7-8):1034-1045
In this paper a method for analysing lateral vibrations in a milling machine spindle is presented including finite-element modelling (FEM), magnetic excitation and inductive displacement measurements of the spindle response. The measurements can be conducted repeatedly without compromising safety procedures regarding human interaction with rotating high speed spindles. The measurements were analysed and compared with the FEM simulations which incorporated a spindle speed sensitive bearing stiffness, a separate mass and stiffness radius and a stiffness radius sensitive shear deformation factor. The effect of the gyroscopic moment and the speed dependent bearing stiffness on the system dynamics were studied for different spindle speeds. Simulated mode shapes were experimentally verified by a scanning laser doppler vibrometer. With increased spindle speed, a substantial change of the eigenfrequencies of the bearing-related eigenmodes was detected both in the simulations and in the measurements. The centrifugal force that acted on the bearing balls resulted in a softening of the bearing stiffness. This softening was shown to be more influential on the system dynamics than the gyroscopic moment of the rotor. The study performed indicates that predictions of high speed milling stability based on 0 rpm tap-test can be inadequate. 相似文献
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Application of a two-level optimization process to conceptual structural design of a machine tool 总被引:1,自引:0,他引:1
Bi-Chu Wu Gin-Shu Young Te-Yen Huang 《International Journal of Machine Tools and Manufacture》2000,40(6):783-794
This paper proposes a modified two-level optimization approach for the concept design of a machine tool. The lower level of optimization is applied to each structural part of the tool and the upper level to the machine tool as an integrated system. When frequent modification of design specifications is required and re-use of previous design experience is preferred, the proposed approach is efficient because of the approximation functions used. Examples presented in the paper show that the principal dimensions of all the structural parts can be determined, minimizing the weight of the machine while maintaining sufficient stiffness. 相似文献
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Estimation of machine tool feed drive inclination from current measurements and a mathematical model 总被引:2,自引:0,他引:2
Young Hun Jeong Byung-Kwon Min Dong-Woo Cho 《International Journal of Machine Tools and Manufacture》2006,46(12-13):1343-1349
Leveling is an important part of a machine tool installation process because it significantly influences the product quality, machine tool accuracy, and machine lifetime. Conventional leveling procedures are performed by skilled engineers using leveling instruments such as spirit or electronic levels. It is difficult to monitor the level of a machine tool because an accurate leveling instrument is expensive and difficult to install. Therefore, a novel methodology for estimating the inclination angle of a machine tool feed drive is proposed in this paper to overcome the difficulties of leveling. The proposed methodology utilizes motor current measurements and a new mathematical model of the machine tool feed drive that considers the inclination. Experimental results showed that the proposed method successfully estimates the inclination angle and enhances the accuracy of the machine tool feed drive model by considering the inclination effects. 相似文献