Active force feedback in industrial robotic assembly: A case study

This paper describes the application of a robot with active force feedback to an industrial assembly operation involving fragile, medium-sized workpieces supplied with large position and orientation uncertainties. It is shown that active force feedback yields a better and more reliable technical solution than passive force feedback. In addition, active force feedback is also economically justified, since the passive solution requires additional peripheral equipment in order to deal with the large uncertainties. The active force feedback approach presented is general in nature and not application dependent.     

基于切削层形状的动态铣削力试验研究及建模

选取轴向切深、每齿进给量、径向切深和主轴转速为试验因素,采用YDX-Ⅲ9702型压电式铣削测力仪,进行了动态铣削力正交实验。针对立铣刀侧铣加工,研究了单刃铣削的临界条件,为设计试验方案提供了理论依据。结合铣削过程,采用角度积分方法求解铣削力模型,避免了轴向积分的繁琐计算。精确地建立了简捷且适应性强的基于切削层形状的动态铣削力预测模型,模型的仿真结果和试验数据相吻合。     

多刃均布式深孔镗刀的建模及切削参数的确定

深孔镗削过程中,设置合理的切削参数可有效减小切削系统的振动.基于矢量法建立多刃均布式深孔镗刀的切削角度模型,利用Pro/E建立几何模型并生成中性几何文件,通过Ansys有限元法,计算不同切削条件下,镗刀的受力情况,分析其最大应力应变曲线,确定出合理的切削参数.     

Specific cutting force coefficients modeling of end milling by neural network

In a high precision vertical machining center, the estimation of cutting forces is important for many reasons such as prediction of chatter vibration, surface roughness and so on. The cutting forces are difficult to predict because they are very complex and time variant. In order to predict the cutting forces of end-milling processes for various cutting conditions, their mathematical model is important and the model is based on chip load, cutting geometry, and the relationship between cutting forces and chip loads. Specific cutting force coefficients of the model have been obtained as interpolation function types by averaging forces of cutting tests. In this paper the coefficients are obtained by neural network and the results of the conventional method and those of the proposed method are compared. The results show that the neural network method gives more correct values than the function type and that in the learning stage as the omitted number of experimental data increase the average errors increase as well.     

金刚石圆锯片锯切花岗石的切削力双因素实验研究

基于金刚石圆锯片锯切五莲红花岗石的双因素实验,对切削速度和进给速度与切削力的关系进行研究.通过极差分析和趋势图得出进给速度是影响切削力Fx、Fy、Fz的主要因素,切削力随切削速度的增大而减小,随进给速度的增大而增大.通过回归分析建立了切削力数学模型,为生产中根据给定的加工参数来预测切削力提供了理论支持.     

切削刃数量对工件切削力及温度影响的仿真研究

通过仿真软件对切削过程建模,并采用不同数量的切削刃对工件进行切削仿真计算,查看其切削数目对加工工件影响。通过仿真计算可以看出,不同数量的切削刃对刀具的温度和作用力有一定的影响:随着切削刃的增加主轴的受力更为平稳,但是其温升加剧;而采用少切削刃则能够获得较少的温升但是其受力波动较大。随着切削速度的提升,多切削刃的温度随着转速提升显著上升。     

Dynamic characteristics of piezoelectric six-dimensional heavy force/moment sensor for large-load robotic manipulator

This paper presents research on dynamic characteristics of a piezoelectric six-dimensional heavy force/moment sensor for a large-load robotic manipulator. The theory on dynamic characteristics of the sensor structure is analyzed, and a mathematical model of the sensor dynamics, decoupled into separate vibration modes, is provided. This model is complemented by dynamic mode analysis of the sensor by finite-element modeling (FEM; ANSYS software). A dynamic calibration experiment is designed, and methods and principles for measurements and data analysis are provided. The characteristic dynamic vibration modes of the piezoelectric force/moment sensor are extracted by analyzing experimental data, yielding amplitude frequency and phase frequency curves of the transfer function linking the excitation loads with the output signals of the transducer. The results of the dynamic calibration experiment demonstrate the good dynamic characteristics of the piezoelectric six-dimensional heavy force/moment sensor. The natural frequencies in the three force directions are high, with values close 2000 Hz. This demonstrates the applicability of the presented six-dimensional heavy force/moment sensor to large industrial robotic manipulators.     

Design and experimental study of an end effector for robotic drilling

This paper presents the development of a drill end effector for use on industrial robots. The end effector has low weight and high rigidity. The drill end effector is fully programmable and will realize different drilling mode. The real-time force feedback can detect dull or broken bits, drill to breakthrough, and plot thrust force while drilling. Additionally, the end effector can also be equipped with a coolant/lubricant device. Based on the drill end effector, an experimental study on dry drilling of Ti-6Al-4V alloy and 7075-T6 alloy bimetal stacks was performed by using an uncoated cemented carbide drill. The hole quality (hole size, surface roughness) and thrust force were evaluated at various spindle speeds, feed rates, stacking sequence, and clamp force. This study indicates that the spindle speed and feed rate have an effect on the hole quality and thrust force by means of changing the temperature and plastic deformation of cutting zone. The results show that drilling 7075-T6 alloy firstly would be most efficient because of the high hole quality and the low thrust force. It was also found that high clamp force is helpful to improve the hole quality.     

基于应变传感器的切削力测试装置实验研究

为了提高应变式切削力测试装置的动态性能,建立了测试装置的动力学方程,利用有限元软件分析了敏感元件的应变分布规律,并进行了装置的结构设计;开发了包含740B02压电式应变传感器、DH5863电荷放大器和PXI-6254数据采集卡的实验装置,通过测量敏感元件的应变,实现了切削力的动态测试。切削实验结果表明,该测试装置结构简单、动态特性较好,适用于较低转速下的切削力实时测量。     

五轴数控滚齿机切削力误差综合运动学建模

根据数控滚齿机运动的实际情况,分析了机床运动副的运动学原理,利用齐次坐标变换对一台包含3个移动轴和3个转动轴的四联动数控滚齿机建立了切削力误差综合数学模型.该分析方法可为其他类型的多轴数控机床误差综合建模及补偿提供理论参考.     

单刀片镗削加工时的力学建模

介绍镗削加工的力学模型.沿切削刃切屑厚度的分布,被作为刀具刃倾角、刀尖圆弧半径、切削深度和进给量的函数被建模.使用机械的和直角到斜角切削转变两种方法,建立该过程的切削力学模型。     

基于两级神经网络分析的切削力与切削功率的研究

基于多层神经网络原理,建立了切削深度、进给量和刀具耐用度为输入,以切削速度为输出的第一级神经网络.构造了切削深度和进给量和切削速度为输入,切削力与切削功率为输出的第二级神经网络.获得满足刀具耐用度条件下的切削速度、切削力和切削功率的插值计算模型建立方法.摆脱了传统经验公式的拟合计算的缺陷.为实现系统在线监测分析提供条件.     

刀具钝化对切削力及表面粗糙度的影响

目前有关刀具钝化对切削力和加工零件表面粗糙度的影响的研究比较少.通过单因素法对比试验,分别测出在不同切削参数下刀具钝化引起的切削力及加工后零件表面粗糙度的变化.分析结果表明,随着切削速度的增加,刀具钝化后的切削力增加了,Fx和Fz方向增加比较明显;随着径向、轴向切深的增加,钝化刀具切削时的切削力增加了,F2增加的最明显.随着切削速度、径向切深及轴向切深的增加,表面粗糙度都明显减小,加工工件的表面质量得以改善.     

Electromechanical coupling modeling simulation and experimental study of crawler

The electromechanical coupling performance of crawler machinery is investigated. A dynamic equation of electromechanical coupling of crawler machinery is established under multi-typical working conditions. The variation in performance of electromechanical parameters during unstable operations over time is analyzed using the virtual prototype and electromechanical coupling model of crawler machinery. The correctness of the electromechanical coupling model is confirmed by comparing the theoretical analysis, virtual prototype simulation, and physical prototype results. This study provides accurate and valuable theoretical methods and fundamental knowledge to analyze the electromechanical and road driving performance as well as to develop and design a crawler machinery.

     

微量油膜附水滴切削试验研究

论述微量油膜附水滴(Oil on Water,OoW)加工液发生原理和冷却润滑特点.针对该切削液的冷却润滑特点进行车削试验研究,并在同干切削和乳化液冷却润滑加工方式对比研究的基础上,通过对切削力、平均摩擦因数和切屑形态的研究分析,揭示出微量油膜附水滴具有良好的冷却润滑效果.