基于PH曲线五轴数控插补策略的研究
发布时间：2018-10-18 15:35
【摘要】：科学知识的不断融合和制造市场竞争的日趋激烈,对机械制造的加工精度和效率提出了更高的要求。代表制造水平的数控技术正向着高速、高精和多轴加工方向发展。五轴加工技术能够一次性加工比较复杂的自由曲面零件,正逐渐取代传统的三轴加工。在对自由曲面进行加工时,通常采用微段直线逼近加工曲线的方法。这种方法导致了庞大的数控加工程序,使得存储和传输的负荷非常大,并且速度不连续降低了加工质量。样条曲线插补可以降低数控程序数量,降低速度波动,从而提高表面加工质量。PH曲线是一种拥有许多优良特性的多项式曲线。它拥有能够精确计算的弧长和精确表示的等距线,并且保持了与Bezier曲线的完全一致性。因此本文针对PH曲线在五轴数控系统中的插补策略进行研究。本文首先在Farouki的CC(cubic-cubic)准则插值算法的基础上提出了数据点消去的逼近算法,减少传统算法的计算量以提高效率。其次,提出以弧长为参数的加减速控制策略,缩短机床低速定位时间和降低机床冲击;对CAM软件生成的CLS文件进行后置处理,生成空间五次PH曲线并用于五轴数控插补的算法。最后,设定五轴数控插补中PH曲线的插补G指令以及处理机制,通过PH曲线样条插补算法和曲面加工仿真验证了理论的正确性和可行性。
[Abstract]:With the continuous integration of scientific knowledge and the increasingly fierce competition in the manufacturing market, higher requirements for machining accuracy and efficiency have been put forward. NC technology, which represents manufacturing level, is developing towards high speed, high precision and multi-axis machining. Five-axis machining technology can process complex free-form parts in one-time, which is gradually replacing the traditional three-axis machining. When machining free-form surfaces, micro-segment straight lines are usually used to approximate the machining curves. This method leads to a large number of NC machining programs, which makes the load of storage and transmission very large, and the speed discontinuity reduces the machining quality. Spline curve interpolation can reduce the number of NC programs, reduce the fluctuation of speed, and improve the quality of surface machining. PH curve is a polynomial curve with many excellent characteristics. It has an exact arc length and an exact representation of the isometric line, and maintains the complete agreement with the Bezier curve. Therefore, the interpolation strategy of PH curve in five-axis NC system is studied in this paper. In this paper, based on Farouki's CC (cubic-cubic) criterion interpolation algorithm, a data point elimination approximation algorithm is proposed to reduce the computational complexity of the traditional algorithm to improve the efficiency. Secondly, an acceleration and deceleration control strategy with arc length as a parameter is proposed to shorten the low speed positioning time and reduce the impact of machine tools, and to post process the CLS files generated by CAM software to generate the PH curve of five times space and to be used in the five-axis NC interpolation algorithm. Finally, the G instruction and processing mechanism of PH curve interpolation are set up in five-axis NC interpolation. The correctness and feasibility of the theory are verified by PH curve spline interpolation algorithm and surface machining simulation.
【学位授予单位】：辽宁科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG659
本文编号：2279565
[Abstract]:With the continuous integration of scientific knowledge and the increasingly fierce competition in the manufacturing market, higher requirements for machining accuracy and efficiency have been put forward. NC technology, which represents manufacturing level, is developing towards high speed, high precision and multi-axis machining. Five-axis machining technology can process complex free-form parts in one-time, which is gradually replacing the traditional three-axis machining. When machining free-form surfaces, micro-segment straight lines are usually used to approximate the machining curves. This method leads to a large number of NC machining programs, which makes the load of storage and transmission very large, and the speed discontinuity reduces the machining quality. Spline curve interpolation can reduce the number of NC programs, reduce the fluctuation of speed, and improve the quality of surface machining. PH curve is a polynomial curve with many excellent characteristics. It has an exact arc length and an exact representation of the isometric line, and maintains the complete agreement with the Bezier curve. Therefore, the interpolation strategy of PH curve in five-axis NC system is studied in this paper. In this paper, based on Farouki's CC (cubic-cubic) criterion interpolation algorithm, a data point elimination approximation algorithm is proposed to reduce the computational complexity of the traditional algorithm to improve the efficiency. Secondly, an acceleration and deceleration control strategy with arc length as a parameter is proposed to shorten the low speed positioning time and reduce the impact of machine tools, and to post process the CLS files generated by CAM software to generate the PH curve of five times space and to be used in the five-axis NC interpolation algorithm. Finally, the G instruction and processing mechanism of PH curve interpolation are set up in five-axis NC interpolation. The correctness and feasibility of the theory are verified by PH curve spline interpolation algorithm and surface machining simulation.
【学位授予单位】：辽宁科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG659
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