共查询到20条相似文献,搜索用时 25 毫秒
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A hybrid 5-axis CNC milling machine 总被引:1,自引:0,他引:1
5-Axis CNC milling machines are important in a number of industries ranging from aerospace to consumer-die-mold machining because they can deliver high machining accuracy with a spindle tilting capacity. Most of these machines have serial mechanisms so that modest static and dynamic stiffness become very critical design issues when high speed machining capability is required. Parallel mechanisms have recently received attention from machine tool designers because of their inherent potential for stiffness and because of their compactness. However, much of the promised advantages of parallel machines only occur within a very small region of their workspace. We discuss some of the kinematic and structural challenges to extract machining performance from serial and parallel machines. We compare a hybrid machine, which combines serial and parallel mechanisms, with typical serial and parallel machines such as Euler angle machines and a hexapod. In particular, we consider singularities, reversal characteristics, and manufacturability. We show that hybrid machines can benefit from the advantages of serial and parallel mechanisms while avoiding most potential pitfalls. However, hybrid structures can suffer from the manufacturing problem of over-constraint. We show that the degree of over-constraint depends on machine size. We have designed a small hybrid 5-axis motion platform, the MIT-SS-1, which can tolerate this over-constraint through a novel layout of axes. We show that this structure has potential as a small 5-axis CNC milling machine. 相似文献
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为了在自由曲面的弹性研抛中 ,获得稳定的动力学特性和加工效果 ,开发了一种由“3轴并联 + 2轴串联”构成的新型 5自由度混联虚拟轴研抛机床。采用柔性多体系统动力学方法 ,建立了基于Lagrange方程的空间刚 柔耦合动力学模型 ;考虑研抛机床整体的刚性运动与各支链弹性变形间的相互作用及耦合 ,将机床的各个支链和平台看作独立子结构 ,建立各自的动力学方程 ,根据子结构之间的约束关系建立了系统约束动力学方程 ;通过动力学仿真分析 ,获得了较稳定的动力学特性 相似文献
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6-UPS型并联机构的刚体动力学模型 总被引:15,自引:0,他引:15
建立了6-UPS型并联机构的动力学模型。为了能使动力学模型包含所有构件的重力和惯性力,以6-UPS并联机构的支链为研究对象,运用D-H方法建立了各构件的坐标系,推导了支链的运动学反解的解析方程,并给出了各个构件的速度、加速度与动平台的速度、加速度的映射关系。然后用牛顿-欧拉方法推导了6-UPS并联机构的动力学模型,为支链中各个构件支反力的求解和整个机构的动力学分析奠定了基础。最后以并联机床为例,运用动力学模型进行了实际计算并绘制了连杆驱动力的变化曲线。 相似文献
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Jun Wu Jinsong Wang Tiemin Li Liping Wang 《The International Journal of Advanced Manufacturing Technology》2007,34(3-4):413-420
This paper focuses on the dynamic characteristics of the two degree-of-freedom (DOF) planar parallel manipulator of a heavy
duty hybrid machine tool. The Newton-Euler approach is employed to derive the inverse dynamic equation of the parallel manipulator.
According to the motion planning of the cutting tool, dynamic simulation without cutting force is performed, and the ratio
of the masses of counterweights to that of moving parts (not including the counterweight) is optimized. It demonstrates that
the manipulator which is designed with over constraint can improve the dynamic behaviour. Furthermore, the cutting force model
for face milling is introduced and the dynamic simulation with the dynamic cutting force is carried out. Simulation shows
that the oscillation of cutting force is one cause of the vibration of the machine tool in the milling process. In the detailed
design, some modification in the structure of the machine tool is made to suppress the vibration. 相似文献
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一种新型运动副及其在并联机床上的应用 总被引:2,自引:2,他引:0
提出了一种基于新型运动副——复合球铰的虚拟轴机床,它是由5-SPS分支组成的并联机构,其中3个分支汇交于一个三重球铰,另2个分支汇交于一个二重球铰,两个球铰固接在一起形成一个复合球铰,代替了并联机构的活动平台,而且机床主轴位于复合球铰中心线上。这种基于复合球铰的5个分支新型虚拟轴机床与基于Stewart平台机构的6个分支的虚拟轴机床相比具有同样多的实用自由度,并且机床结构简单、解耦,其正反解计算及控制亦相对简单。探讨了5分支机床的结构形式,尤其对关键结构——复合球铰的结构,机构位置反解,以及一定姿态下的可达工作空间进行了分析和计算。这种新型虚拟轴机床在空间曲面加工领域将有着广泛的应用前景。 相似文献
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三杆混联数控机床的运动学研究 总被引:4,自引:0,他引:4
介绍了一种3-TPS(RRR)型混联机床,该机床既可进行立式加工,将工作头旋转一定角度后又可实现卧式加工。在工作头下面安装一个数控转台,并配置自动换刀系统后,机床可进化为一台五轴联动的数控加工中心。在分析其约束机构的基础上,给出了机构的位置、速度、加速度逆解方程及雅可比矩阵的计算公式,并进行了机床的工作空间分析。理论分析表明,3-TPS(RRR)型混联机床运动学方程形式简洁,计算简单,控制计算方便,在运动空间内无运动干涉和耦合,无奇异点和不定形位,可操作性良好,有效工作空间大。 相似文献
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Kinematic calibration of gantry hybrid machine tool based on estimation error and local measurement information 总被引:1,自引:0,他引:1
Xiaoqiang Tang Jinsong Wang Men Gao 《The International Journal of Advanced Manufacturing Technology》2005,26(4):382-390
This paper presents the kinematic calibration of a four degrees-of-freedom (DOF) hybrid machine tool based on a novel planar 3-DOFs parallel mechanism and a long movement of the worktable. Closed-form solutions are developed for both the inverse and direct kinematics about the parallel mechanism. The error model is built and the mechanism accuracy is investigated. Two types of kinematic calibration method are proposed by a simple measurement device. The first type of calibration method is based on estimation error, and can easy improve the machine tool accuracy quickly by estimating the error trends. The second type of kinematic calibration method is based on local measurement information, which includes the position errors and does not include the pose errors of the machine tool. The calibration tests showed the effectiveness of the calibration methods, which can be useful for the similar types of parallel machine tool. 相似文献
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新型3T2R龙门式混联机床动力学模型 总被引:2,自引:0,他引:2
提出了一种以能实现沿X、Z轴平移和绕X、Y轴转动的新型并联机构2-RPU2-UPS作为主体,辅以能实现主体Y轴滑动的直线导轨来共同实现五坐标联动加工的一种新型龙门式混联机床的机构设计方案。运用螺旋理论分析了该机床实现3T2R运动原理,计算出该机床的自由度,进行输入选取与论证,并进行机床机构奇异分析,提出减少奇异的参数设计条件。建立该机床的位置反解数学模型,推导出了该机床的速度雅可比矩阵和加速度分析表达式,求解了该机床的位置反解、速度和加速度。基于虚功原理和该机床的运动学模型建立该机床的动力学模型,并采用Adams软件对该机床动力学进行模拟仿真,模拟结果表明理论结果完全正确。 相似文献
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三杆混联数控机床的动力学 总被引:2,自引:0,他引:2
为了考察3-TPS型立卧转换式混联数控机床的动态特性、解决机床构件结构参数的选择和优化以及机床的控制等技术问题,使用拉格朗日方法研究了该种混联数控机床的动力学问题。首先根据机床的结构特点将拉格朗日动力学方程展开成表示在笛卡尔坐标中的标准形式,并将机床按照其结构特点分为动平台、三个驱动支链和平行约束机构三个子系统,然后分别推导了三个子系统的动能和势能的计算模型,在此基础上建立了机床在笛卡尔坐标中的拉格朗日动力学方程,并根据拉格朗日动力学方程的标准形式用递推方法得出了动力学方程中三个子系统的惯量矩阵M、科氏项系数V和重力系数G等各系数的计算公式,最后总结出了相应的算法。机床的这种动力学模型概念清楚,计算比较简单,可以满足机床的控制要求。 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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一种混联型虚拟轴机床的位置正确与工作空间分析 总被引:5,自引:0,他引:5
提出了以4自由度空间并联机构作为主进给机构,辅以双向移动工作台实现多坐标数控加工的一种混联型虚拟轴机床的配置方案,推导出了主进给机构位置正确的封闭方程,基于曲面分析方法分析了主进给机构及其虚拟轴机床的工作空间,并给出了数值实例。 相似文献