共查询到20条相似文献,搜索用时 93 毫秒
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微进给机构是超精密加工设备中实现精密定位的重要组成部分,由于精密磨削时磨削量数量级的减小,热变形的问题更加突出,成为影响平台定位精度的主要因素.运用I-DEAS软件,针对一种精密磨削用多自由度辅助微进给平台,对其磨削工件时的温度场进行了分析研究,为进一步探索其热变形的规律奠定了基础. 相似文献
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为补偿精密磨床砂轮的振动对加工精度的影响,设计了一台作为磨床辅助进给装置的微进给工件平台。该工作平台采用压电陶瓷作为驱动机构,弹性铰链作为预紧机构。为了避免压电陶瓷驱动器受到弯矩的作用,在压电陶瓷驱动器的顶部和动平台之间加了一个球形接头。利用弹性铰链的预紧力,实现驱动器和动平台之间的赫兹接触。高精度的电容式位移传感器用来测量动平台的实际输出并形成反馈控制系统。为了消除压电陶瓷的迟、蠕变等非线性,采用了非线性PID控制算法来实现微进给平台的实时控制。采用跟踪微分器对信号进行跟踪并得到其微分信号,提高了控制系统的鲁棒性。通过计算机仿真了所设计的微进给平台的特性和闭环控制算法的有效性。 相似文献
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压电陶瓷微进给工作台的设计及其实验研究 总被引:3,自引:0,他引:3
本文论述了一台由电致伸缩陶瓷制动器驱动的微进给工作以的研制过程,设计了工作台的主体结构,预紧力机构及密封装置,并利用高等材料力学和有限元法优化了主要变形元件,通过HP5528A激光测距系统对其特性进行了测试,工作台最大行程16μm位移分辨率小于0.1μm重复定位精度0.1μm。 相似文献
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D. Zhang D.G. Chetwynd X. Liu Y. Tian 《International Journal of Mechanical Sciences》2006,48(12):1401-1408
A novel three degree of freedom numerically controlled micro-positioning table has been developed, optimized for applications such as improving the machining precision of precision grinders. The table consists of a moving platform, coupled to a base, three piezoelectric actuators and three capacitive sensors. An elastic structure with three notch-type flexure hinges both guides the platform and generates a preload for the piezoelectric actuators. The dimensions of the platform and flexure hinges and the position of flexure hinges are designed with the aid of finite element modeling to provide good stiffness with little bending deformation of the platform. The inverse model of the table is developed for numerical control. Experimental results are compared to the model predictions. The table has a natural frequency of 584 Hz, a resolution of 6 nm, an open loop control stiffness of 104 N/μm at the center of the moving platform and a closed loop control stiffness of 650 N/μm across the working area of the table. 相似文献
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In this study, a new system of optimum in-process electrolytic dressing and a microposition system are developed. This system
can carry out optimum in-process dressing of superabrasive wheels, and gives effective control of the unstable dressing current
and insulating layer.
Therefore, ultraprecision grinding when using an optimum in-process electrolytic dressing system and microposition system
is a good method for efficient mirror-like grinding of brittle materials. 相似文献
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《机械科学与技术》2013,(11):1610-1615
针对3-RRR柔顺微动平台由于输入的直线位移(压电驱动)与被驱动件的转动(R副)不匹配而带来的传动误差问题,首先对不同型式对称四杆机构的直线位移输出特性进行比对,提出了一种较理想的柔顺直线机构-变截面对称四杆机构;其次,以变截面对称四杆机构作为被驱动机构,提出了一种新型3-PRR平面柔顺微动平台,并对该柔顺微动平台进行了运动学分析,得到了平台的正反解以及雅克比矩阵;利用功能转化原理求得平台的刚度矩阵,最后通过有限元软件进行仿真,分析了随机选取的15组位姿。结果表明:与理论位姿间的最大相对误差仅为1.33%,验证了理论分析的正确性。 相似文献
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为解决微定位平台大行程与高精度之间的矛盾,提出一种新型的3自由度柔性并联机构。该机构三条支链采用特殊方式与动平台相连,使整体机构结构紧凑且具有良好的力学传递性能。同时,机构采用行程大,分辨率高,便于控制的电磁驱动器作为驱动部件,保证机构在不需要引入放大机构的前提下便可获得较大的行程和较高的分辨率。使用大行程柔性铰链代替普通的球铰,降低了加工制造难度和机构刚度模型的求解难度。采用螺旋理论分析了3-P(4S)并联机构末端运动特征,结合单元刚度矩阵法和矩阵位移法推导了3-P(4S)柔性并联机构的静刚度模型,并采用ANSYS进行了分析验证。 相似文献
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超精密加工及其进给驱动技术 总被引:2,自引:0,他引:2
论述了超精密加工的重要意义、主要方法、一些关键技术及在机械制造技术中的作用和地位;介绍了一种直线电机直接驱动的新型超精密进给机构的工作原理和基本结构,较好地解决了超精密加工的精确移动和定位问题。 相似文献
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The increasing use of nano-positioners in a wide variety of laboratory and industrial applications has created a need for
nano-mechatronics education in all engineering disciplines. The subject of nano-mechatronics is broad and interdisciplinary.
This article focuses on the way nano-mechatronics is taught in department of mechanical engineering at Korea Advanced Institute
of Science and Technology (KAIST). As one model of nano-positioning systems, design and experimental methodology is presented
in this article. For design phase, the stiffness and resonant frequencies are found analytically and verified by using a commercial
finite element analysis program. Next, for experimental phase, various tests are performed to access the performances of the
designed nano-positioner, for example, sine-tracking, multi-step response and travel-range check etc. Finally, the definition
of “separation frequency” is described and some comments are discussed. 相似文献
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A numerical procedure to analyze wavy thrust bearings is described. The numerical model is developed by assuming that two circular plates rotate relative to each other. The upper plate is assumed to be flat and rotating, whereas the lower plate is assumed to be stationary and wavy in surface geometry. A Reynolds-equation-based procedure is used to simulate the dynamics engendered by various wavy geometries and loading conditions. The equilibrium position of the journal results from the equilibrium between the forces generated by the fluid-film pressures and the externally applied loads. A numerical small perturbation technique is applied to calculate the linear stiffness and damping characteristics of the bearing at the equilibrium position. Using a three-degrees-of-freedom system with one axial and two rotational displacements, nine linear stiffness coefficients (three principal and six cross-coupled coefficients) and nine linear damping coefficients are calculated. These linear coefficients are then used to calculate the eigenvalues of the system by solving the homogeneous equations of motion. The stability of the bearing system is then expressed using the lowest logarithmic decrement obtained from these eigenvalues. Using this procedure, a parametric study is carried out to examine the effects of external load, location of the applied load, bearing number, and bearing wave amplitude on journal equilibrium position, bearing linear stiffness, damping characteristics, and bearing stability. 相似文献