共查询到20条相似文献,搜索用时 15 毫秒
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针对目前NURBS曲线插补中加减速控制方法不足的问题,实现了加工过程中进给速度的平滑过渡,提出了一种新的NURBS曲线插补方法,包括速度规划和实时插补两个方面。速度规划采用了一种基于曲率自适应的简化计算的S型加减速方法,并结合"双向插补"的思想实时预测减速点,防止产生过大的弓高误差;实时插补则利用Muller插值和Newton迭代法计算了下一周期的插补参数,进而求出了下一时刻到达的空间坐标点。最后与已有插补方法进行了仿真分析比较。研究结果表明,该方法能保证加速度连续和加加速度有界,有效减少弓高误差和进给速度波动,提高机床运行的平稳性。 相似文献
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介绍了数控机床两种超行程保护的工作机理。当机床的某一轴同时触发两个方向的超程警报时,可借助系统诊断功能查询机床PLC的当前状态,结合对机床电气回路的测量,查找并分析故障原因;通过调整行程开关位置并修改相关系统参数,最终排除数控机床的超程故障。 相似文献
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机床出现爬行时,将严重影响加工工件表面质量、表面粗糙度及定位精度,甚至还会影响机床零件的使用寿命,缩短刀具的使用寿命。机床导轨爬行严重时,可导致机床丧失加工能力。主要分析了数控机床爬行的原因及其对策。 相似文献
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X. Zhiming C. Jincheng F. Zhengjin 《The International Journal of Advanced Manufacturing Technology》2002,20(4):270-276
This paper presents a real-time interpolation algorithm for NURBS curves. In contrast to the existing linear and circular
interpolators, the proposed interpolator can maintain small contour errors and feedrate fluctuations. Feedrate components,
acceleration components and the servomotor driving force for each axis are precalculated from the given curve shape and themachine
tool dynamic properties. As a sudden change in the geometrical properties of the tool path can increase contour errors and
cause a sudden change of driving force of each servomotor, a new strategy of variable feedrate machining based on the geometrical
properties of tool path is suggested. Real-time performance measurement of this interpolator is performed to demonstrate its
practical feasibility. 相似文献
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提出了以四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新型并联机床的配置方案。推导了并联机床位置、速度逆解模型 ,设计了面向该并联机床的CNC系统方案。构造了由刀具轨迹计算、位置与速度逆解模型和PVT细插补模式相结合的NURBS曲面直接插补算法 ,并讨论了CNC系统方案实施中的关键技术 相似文献
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数控技术全面支持高速复合机床精度的提升 总被引:1,自引:0,他引:1
文章概括了保证数控机床精度的三个层面的问题:支撑刚度,导向精度和定位精度与刚度。从上述三个方面,重点介绍了数控技术链的各技术环节对实现大连科德数控有限公司KDL1550FH立式车铣复合加工中心和KDW4200FH卧式铣车复合加工中心高速高精度控制的作用。 相似文献
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针对一种基于PLC的开放式数控系统,应用NURBS(Non-Uniform Rational B-Spline)曲线插补技术,对传统的自由曲线插补算法进行改进.同时根据STEP-NC标准对CAD/CAM/CNC一体化的新型数控插补方法进行研究,利用ActiveX技术实现了与CAD系统的数据交换,并在实验数控系统中加以应用.实验结果证明该插补算法可以有效地提高实时插补速度和精度,提高数控系统的工作效率. 相似文献
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蒙斌 《工业仪表与自动化装置》2014,(6):53-55
分析了闭环伺服系统的控制特性和控制要求。对采用光栅作为检测装置的数控机床,指出了影响数控机床控制精度和加工精度的主要因素。提出了对检测反馈信号进行倍频处理,从而提高闭环伺服系统检测精度及控制精度的措施。给出了倍频处理电路和EXE信号处理电路的设计方法。针对光栅使用中可能出现的故障,给出了故障诊断及处理方法。该方法不但可以提高数控机床的控制精度,改善闭环控制系统的特性,而且可以方便地进行测量系统故障的诊断与处理。 相似文献
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In-Hugh Choi Min-Yang Yang Won-Pyo Hong Tae-Sung Jung 《The International Journal of Advanced Manufacturing Technology》2005,25(3-4):325-333
Finish machining of a curved surface is often carried out by an NC system with curve interpolation in the field. This function, called a NURBS interpolation, adopts a feedrate optimizing strategy based on both the geometrical information of the curved path and dynamic properties such as the curvature of the curve, the allowable acceleration and the time constant. However, in the case of a finish cut using a ball-end mill, the curve interpolator needs to take the machining process into account for improved surface roughness, while reducing the polishing time. This surface roughness on high-speed machining is theoretically defined by the feed per tooth and the pickfeed at the given radius of the tool. In this study, the effect of low machinability at the bottom of a tool on surface roughness is also considered. A curve interpolation algorithm is proposed for generating particular feedrate commands that are able to control the roughness of a curved surface. The simulation of the machined surface by the proposed algorithm was carried out, and experimental results are presented. A feedrate scheme that depends on the inclination angle has important potential application in part finishes consistent with prescribed surface roughness. The results show that the proposed algorithm is potentially useful for roughness-controlled machining of curved surface products. 相似文献