基于“PBL教学方法”的数控加工实训教学设计

本文应用职业教育课程改革中应用广泛的“PBL教学法”对数控操作中级工实训这门课程进行了教学设计，并以其中一个教学模块进行了单元设计作为示例。     

深度学习框架下融合注意机制的机床运动精度劣化预示

数控机床运动精度衰退是一个动态的演化过程。为尽早发现数控机床潜在的失效风险,挖掘蕴含在各类监测数据序列中的运动精度演化特征,在深度门控循环网络（Gated recurrent unit,GRU）框架下,提出了一种融合注意机制的数控机床运动精度劣化预示方法。为了克服传统深度卷积神经网络不能学习时序特征的缺陷,采用深度编码器-解码器框架,提出基于深度GRU的运动精度深度学习建模方法,以数据驱动,自动挖掘运动精度与振动、温度、电流等状态信号时间序列的时空特征,预测运动精度,根据预测曲线对机床劣化趋势进行预示。为了增强主要状态信号和关键时间点的信息表达,提高精度劣化预测的准确性,提出一种在深度学习框架中融合注意机制的方法,建立状态参量的注意网络,计算振动、温度等状态信号与机床精度间关联程度,自动调整各信号的权值;进一步,建立时序注意网络自主选取精度劣化历史信息关键时间点,以提升较长时间段预示的准确性。实验结果表明,基于深度学习网络与注意机制的预示模型可以很好地追踪数控机床运动精度的劣化趋势和规律,有较高的预测精度,优于传统方法。     

宏程序在斜椭圆车削中的应用

数控车床在车削斜椭圆轮廓时,常用的加工指令难以完成曲面加工,必须采用宏程序编程。通过旋转转换方程确定斜椭圆的参数方程,编制出(包含宏程序)实际加工程序。文章以FANUC0i-mateTC数控系统为例,介绍宏程序在斜椭圆车削中的应用。     

关于数控加工工艺标准化的探讨

随着科学技术水平的不断提升,数控技术得以快速发展。建构数控加工工艺标准化体系具有必要性,能够规范数控技术操作。文章主要论述了数控加工工艺标准过程与内容的设计,并提出数控加工工艺标准化的设计。     

Software fault location of CNC system

In order to quickly and accurately locate the fault of CNC software and improve the reliability of CNC system,an improved algorithm of similar path and fuzzy judgment is introduced into the fault location of CNC software. Firstly,according to the execution information recorded by monitor,the failed path is generated;secondly,the similar path set can be obtained from control flow graph and failed path;then the search scope of suspicious codes can be reduced by program slicing;finally,the fuzzy mathematics is performed to judge suspicious codes. In addition,the experiment on the NURBS interpolation injected bugs is carried out. The experiment results indicate that the proposed method is effective in locating the fault of the CNC software.     

我国数控木工机械的发展现状及自动化技术的研发方向

论述了我国数控木工机械数控化率估算的分类基础,提出数控木工机械的定义、判定低档和高档数控木工机械的标准,明确指出我国木工机械数控化率已经达到42%。分析了我国木工机械种类分类定义,介绍了德国木工机械的分类方法。阐述了我国木工机械软件和硬件以及数控带锯机、数控截段锯切设备、数控刨切机床、数控车床、数控砂光机等技术的发展现状,我国木工机械自动化技术的研发步骤及方向。我国用短短5年的时间,完成了欧洲木工机械发达国家30年的数控木工机械开发历程,我国木工机械在产值上超过德国可能仅需要6～8年的时间。     

数字化技术在重组装饰材设计中的应用与研究（Ⅱ）

重组装饰材是天然木材的完美替代品。研究探索了计算机虚拟制造技术在重组装饰材中的应用,为重组装饰材纹理制造提供了新的思路。     

高密度纤维板数控雕刻加工工艺研究

本文以高密度纤维板为原料,采用正交试验探究雕刻工艺对产品质量的影响,得到在该试验水平范围内最优雕刻工艺参数:主轴转速为24000 r·min-1,路径间距为0.20 mm,加工速度为6000 mm·min-1.为数控雕刻在高密度纤维板上应用提供了参考和技术支撑.     

数控机床导轨滑块结合部组建模与参数辨识方法研究

提出理论建模-动态试验-多目标优化技术的广义结合部组参数辨识方法,该方法在综合考虑结合部组与被连接件间的双重耦合特性、构建导轨滑块系统广义等效结合部组模型的基础上,通过结构凝聚技术降低计算成本保证计算精度,最终推导得到约束状态下以阻抗形式表达的整体动力学模型,基于未知传递函数/阻抗数据信息获取,将理论建模、动态试验与多目标优化问题求解相结合对结合部参数进行辨识。实例表明,该广义结合部组参数辨识方法的辨识精度较高,模态频率及频响函数的误差非常小,该辨识方法有效。     

Nitrate leaching in a silage maize field under different irrigation and nitrogen fertilizer rates

Quantification of the interactive effects of nitrogen (N) and water on nitrate (NO₃) loss provides an important insight for more effective N and water management. The goal of this study was to evaluate the effect of different irrigation and nitrogen fertilizer levels on nitrate-nitrogen (NO₃-N) leaching in a silage maize field. The experiment included four irrigation levels (0.7, 0.85, 1.0, and 1.13 of soil moisture depletion, SMD) and three N fertilization levels (0, 142, and 189 kg N ha⁻¹), with three replications. Ceramic suction cups were used to extract soil solution at 30 and 60 cm soil depths for all 36 experimental plots. Soil NO₃-N content of 0-30 and 30-60-cm layers were evaluated at planting and harvest maturity. Total N uptake (NU) by the crop was also determined. Maximum NO₃-N leaching out of the 60-cm soil layer was 8.43 kg N ha⁻¹, for the 142 kg N ha⁻¹ and over irrigation (1.13 SMD) treatment. The minimum and maximum seasonal average NO₃ concentration at the 60 cm depth was 46 and 138 mg l⁻¹, respectively. Based on our findings, it is possible to control NO₃ leaching out of the root zone during the growing season with a proper combination of irrigation and fertilizer management.