叶片复杂曲面的机器人抛磨工艺规划

为了实现复杂曲面工件的智能抛磨加工,对叶片复杂曲面进行机器人抛磨工艺规划。对抛磨点位置规划算法和基于最大接触原则的抛磨姿态规划算法进行了研究。首先,通过平行截面法获得抛磨路径割线,以非均匀有理B样条(NURBS)曲线描述。接着,提取曲线特征参数,根据设定的阈值进行抛磨点规划,再基于抛磨轮与工件的最大接触原则进行抛磨点姿态规划,从而得到完整的抛磨路径。然后,将工件位姿从工件坐标系转换到TCP坐标系。最后,搭建了柔性抛磨系统仿真平台生成机器人控制程序。实验结果表明,此方法规划的路径可用于叶片复杂曲面的机器人抛磨加工。分别用本文规划所得路径和CAM软件规划所得路径对叶片进行抛磨加工,测得表面粗糙度分别为0.695~0.930μm和2.803~3.243μm。本文提出的抛磨位姿规划方法可用于复杂曲面工件的抛磨路径规划,使工具和工件保持最大接触,从而避免了位姿不合理所产生的过抛和欠抛。     

叶片机器人砂带磨抛点云匹配算法优化

为解决机器人磨抛路径中工件坐标系难以计算的问题及校正工件装夹误差,将三维点云配准技术应用到叶片机器人砂带磨抛系统中。由三维激光扫描仪扫描工件型面获得工件点云,采用基于主成分分析(PCA)的全局配准算法和改进的迭代最近点(ICP)算法完成了扫描点云和工件模型离散点云间以及不同工件扫描点云间的匹配,以获取工件坐标系和校正工件装夹误差。相关仿真和试验结果表明,优化后的算法在匹配速度与精度上有了长足改进,且加工后产品精度和质量都能满足实际加工要求。     

面向复杂曲面的机器人砂带磨抛路径规划及后处理研究

针对机器人砂带磨抛复杂曲面叶片问题,对叶片内外型面和进排气边的磨抛路径规划及后处理技术进行了研究,对复杂曲面叶片的机器人砂带磨抛路径规划的计算效率及加工效率进行了分析,提出了一种将基于等残留高度法的笛卡尔空间计算的磨抛行距转化为参数域空间的磨抛行距的方法,并将机器人砂带磨抛复杂曲面叶片接触轮的中心坐标位置、支撑轴矢量以及轴线矢量数据后处理为机器人的位姿信息,利用机器人砂带磨抛系统装备实验平台对复杂曲面叶片进行了实际的加工实验。研究结果表明:所提出的刀路规划和后处理技术能够有效地解决机器人砂带磨抛复杂曲面叶片的问题,具有加工路径总长短以及路径条数少的特点,计算简单、加工效率高、加工表面质量好。     

钻尖直线刃后刀面的砂轮磨削轨迹算法研究

为了提高钻尖后刀面的加工精度和保证砂轮磨削姿态的灵活性,研究了钻尖直线刃后刀面数控磨削过程中的砂轮轨迹计算方法。定义了钻尖直线刃后刀面的结构参数,建立了钻尖直线刃线及后刀面的数学模型;定义了钻尖直线刃后刀面的坐标系和砂轮基准磨削姿态;在此基础上,采用坐标变换矩阵描述砂轮运动方式,借助运动学原理推导了基于工件坐标系的砂轮磨削位置和姿态的计算方法。该方法保证了钻尖直线刃后刀面的精度,可灵活调整砂轮磨削姿态。基于VC++环境开发了计算程序,并进行仿真加工验证,验证了算法的有效性。     

基于刚度定向的工业机器人铣削姿态优化研究

针对工业机器人结构非对称引起的主刚度方向难以确定、因刚度低导致的铣削过程中容易发生模态耦合颤振的问题,提出了一种机器人加工系统主刚度定向方法,并利用机器人功能冗余特性优化姿态,以提高铣削过程的稳定性。计算工业机器人末端笛卡儿坐标系中的刚度椭球,确定切削平面内机器人的主刚度方向;通过建立加工系统的动力学模型,得到机器人铣削模态耦合颤振的稳定性判据;基于刚度定向方法,提出一种机器人铣削姿态优化算法。实验结果表明,在不改变其他参数的情况下,通过优化工业机器人姿态,可以保证机器人沿给定轨迹加工的稳定性。     

面向熔射快速制模的机器人自动研磨系统的开发

为解决熔射制造大中型汽车覆盖件模具过程中人工研磨时间长、劳动强度大等问题,建立了面向熔射快速制模的机器人自动研磨系统.在该系统上进行机器人研磨工艺参数实验研究,得到了研磨角度、机器人行走速度和路径对研磨表面质量的影响规律;在此基础上选择合适的研磨条件,在通过等离子熔射制造的模具表面皮膜上进行了研磨实验.实验研究结果表明,保持适当的研磨压力,选取合理的机器人行走速度、研磨角度、进给量,可得到较好的研磨效果.该机器人自动研磨系统适用于熔射制造的模具及一般模具的研磨过程.     

Composite adaptive control of belt polishing force for aero-engine blade

The existing methods for blade polishing mainly focus on robot polishing and manual grinding.Due to the difficulty in high-precision control of the polishing force,the blade surface precision is very low in robot polishing,in particular,quality of the inlet and exhaust edges can not satisfy the processing requirements.Manual grinding has low efficiency,high labor intensity and unstable processing quality,moreover,the polished surface is vulnerable to burn,and the surface precision and integrity are difficult to ensure.In order to further improve the profile accuracy and surface quality,a pneumatic flexible polishing force-exerting mechanism is designed and a dual-mode switching composite adaptive control(DSCAC) strategy is proposed,which combines Bang-Bang control and model reference adaptive control based on fuzzy neural network(MRACFNN) together.By the mode decision-making mechanism,Bang-Bang control is used to track the control command signal quickly when the actual polishing force is far away from the target value,and MRACFNN is utilized in smaller error ranges to improve the system robustness and control precision.Based on the mathematical model of the force-exerting mechanism,simulation analysis is implemented on DSCAC.Simulation results show that the output polishing force can better track the given signal.Finally,the blade polishing experiments are carried out on the designed polishing equipment.Experimental results show that DSCAC can effectively mitigate the influence of gas compressibility,valve dead-time effect,valve nonlinear flow,cylinder friction,measurement noise and other interference on the control precision of polishing force,which has high control precision,strong robustness,strong anti-interference ability and other advantages compared with MRACFNN.The proposed research achieves high-precision control of the polishing force,effectively improves the blade machining precision and surface consistency,and significantly reduces the surface roughness.     

A simulation platform for optimal selection of robotic belt grinding system parameters

Robotic belt grinding is an effective process for removing material from geometrically complex workpieces. However, due to the relatively low stiffness of the system, the grinding quality is prone to inaccuracies caused by system dynamics. In order to control the quality of the grinding process, a profound understanding of the system is required. This paper presents a platform for comprehensive modeling and simulation of the robotic belt grinding system. The system kinematics model is based on the CAD model of the workpiece in composition with robot kinematics. The dynamics model is a comprehensive combination of the dynamics of the robot, the grinder, and the interaction between the grinder and the workpiece. A material removal model of the grinding process, which can adapt to workpieces with complicated shapes, is also developed and presented. The system simulation shows that optimal selection of key control parameters of the grinder and proper selection of robot control strategies can efficiently suppress chatter in the grinding process. Furthermore, having the ability to predict material removal rate, the comprehensive simulation platform is also demonstrated to be a strong tool in selecting the grinding process key parameters, namely, robotic velocity and contact force, for the control of material removal to meet dimensional accuracy requirements on workpieces.     

基于重定位的叶片机器人磨抛系统手眼标定算法

针对叶片机器人磨抛系统中手眼标定存在人工误差、二次误差等因素导致标定精度差等问题,提出了一种基于"重定位"的手眼标定算法.以拍照式三维扫描仪为标定对象,分析机器人手眼标定数学模型,提出利用标准球在机器人末端坐标系中绕工具中心点做定点变位姿运动的标定方案.通过最小二乘法计算扫描仪坐标系下的"重定位"中心坐标,并根据多空间...     

Mathematical modeling and machining parameter optimization for the surface roughness of face gear grinding

Face gear is an important part in the power transmission of helicopter, but its grinding is a difficult problem. In order to enhance the finishing machining surface quality of face gear, the mathematical formula of the residual height of motion trajectory of abrasive grains was obtained, and the model of grinding surface roughness of face gear was corrected. In addition, machining parameter optimization for grinding surface roughness on a five-axis blade grinding machine was investigated by orthogonal experiment method. The experiment results indicated that disk wheel spindle speed and feed velocity of the disk wheel are more significant effect factors among the three factors. The calculation results of model showed that the maximum error comparing with the experiment results is not more than 13.5 %, which suggests that the mathematical model is reasonable.     

[制造前沿]机器人测量-操作-加工一体化技术研究及其应用

阐述了机器人加工的发展现状与面临的挑战,回顾了机器人测量操作加工一体化所需要的关键技术。以典型的机器人加工过程为例,分析了机器人测量-操作-加工一体化过程中误差的来源,建立了加工误差及其传递模型,并分别计算分析了测量误差、坐标变换误差与机器人执行误差对加工精度的影响。将机器人测量加工一体化方案用于飞机机翼和机身装配垫片的磨削加工,由点云数据得到工业机械臂的加工轨迹和工艺参数规划数据,通过在机械臂末端安装顺应打磨头来消除工件法向的位置误差,实现恒力打磨。实验结果表明,该机器人加工方案能够实现飞机装配垫片的变厚度磨削加工。     

航空发动机叶片数控智能磨削加工技术研究

现有磨削加工技术已经无法满足发动机的需求,故提出航空发动机叶片数控智能磨削加工技术。应用参数线法规划叶片磨削加工轨迹,以此为基础,提取磨削加工余量,模拟与计算对应数值,适当处理获取的叶片磨削加工轨迹与加工余量数据,推出叶片数控智能磨削算法(数控车床转轴、直线轴与压力轴运动控制模型),以此控制数控车床运动姿态,并通过刀位点偏移补偿叶片的反变形误差,实现了航发叶片的数控智能磨削。实验数据表明:应用该技术后叶片型面加工前后粗糙度变化明显;叶片边缘加工误差保持在标准误差范围内;叶片根部粗糙度得到了大幅降低,充分证实了该技术具有可行性。     

奥利康摆线齿锥齿轮铣刀盘刀齿刃磨方法及加工仿真

根据磨轮与刀齿型面的接触条件,提出了奥利康摆线齿锥齿轮铣刀盘条形刀五轴刃磨加工的刀位点计算方法。利用Vericut软件构建了虚拟机床模型和加工环境,进行条形刀五轴刃磨仿真,验证了刀位点和NC代码的正确性。     

Robot machining: recent development and future research issues

Early studies on robot machining were reported in the 1990s. Even though there are continuous worldwide researches on robot machining ever since, the potential of robot applications in machining has yet to be realized. In this paper, the authors will first look into recent development of robot machining. Such development can be roughly categorized into researches on robot machining system development, robot machining path planning, vibration/chatter analysis including path tracking and compensation, dynamic, or stiffness modeling. These researches will obviously improve the accuracy and efficiency of robot machining and provide useful references for developing robot machining systems for tasks once thought to only be capable by CNC machines. In order to advance the technology of robot machining to the next level so that more practical and competitive systems could be developed, the authors suggest that future researches on robot machining should also focus on robot machining efficiency analysis, stiffness map-based path planning, robotic arm link optimization, planning, and scheduling for a line of machining robots.     

双机器人快速原型制造离线编程系统的研制

双机器人快速原型制造离线编程系统主要研究如何自动获取ＣＡＤ模型产生的零件图形的加要数据,并对其进行处理后按机器人的程序格式生成双机器人的加工程序。本文在分析双机器人快速原型加工硬件特点的基础上,建立了双机器人离线编程系统总体结构,研究了各功能模块的关键技术,并用ＩＤＥＦ方法对各功能模块进行了详细设计研制了一套离线编程软件,实现了双机器人加工程序的自动生成。     

机器人砂带磨削路径优化插补算法

为解决经典泰勒插补算法生成的加工轨迹在加工中产生的过切问题,在机器人打磨离线编程系统上进行了机器人打磨路径插补算法的研究。通过对比各种路径刀位点生成方法,提出一种改进的泰勒插补算法。该算法在加工路径曲率变化较大的区域刀位点自适应地致密,避免了弓高误差超差引起的过切;当加工路径较为平滑时,刀位点稀疏,保证加工效率。通过设计优化算法与经典算法的对比磨削试验,验证了该插补算法的有效性。     

Developing an end-of-arm tooling for robotic grinding machining application

Cleaning castings is a common process in manufacturing and there have been various kinds of robotic applications in deburring, polishing, etc. However, robots have not been applied to surface machining because of difficulties in metal removal control. Robotic Vision Systems Inc. is currently engaged in a research effort to develop a robotic disc or wheel grinding unit for surface machining applications. Novel design features, such as passive compliance and visual feedback, will provide system performance that offers more consistent quality and lower production costs than manual methods.     

Closed-loop machining cell for turbine blades

This paper presents an innovative concept of a closed-loop machining cell for turbine blade finishing that integrates a robotic surface finishing device with an electro-optical, non-contact precision measuring system. We propose that a synergistic combination of these leading edge technologies allows us to close the loop between finishing and inspection. Instead of part measurement being a mere off-line verification operation, it can direct the robot to do the necessary work and provide feedback to achieve higher finishing precision. In this paper, we describe the challenges in closing the loop seamlessly and our approach to resolve them. We present the overall architecture in which the part is measured using a multiple cooperative sensor system, and the robot is directed until the desired finish is obtained. We present details on the use of multi-sensor inspection and corresponding integration of the various components (hardware and software). We validate by application to turbine blades that are used commercially. Utilizing the suggested concept, turbine blade manufacturers will benefit by realizing greatly increased product throughput and reduced cost. The potential for generating scrap is reduced, and two separate, time-consuming operations will be consolidated into a single setup. It will also reduce hardware, footprint, maintenance, and energy costs by their sharing of common components. This concept can be extended to similar closed-loop manufacturing cells with minor modifications.     

非金属硬脆材料加工技术的最新进展

综述了近年国内外非金属硬脆材料加工技术的发展和最新研究成果,主要包括在传统磨削技术基础上发展起来的先进磨削技术,加热、超声和摩擦化学反应等辅助能量加工技术,以及激光、等离子、电火花、磨料水射流等高能束加工技术,展望了超精密加工技术的发展前景,旨在为促进我国的非金属硬脆材料优质、高效、低成本加工技术的快速发展提供借鉴。     

一种带缘头避让的叶片高效螺旋加工方法

针对航空发动机叶片螺旋铣加工中前后缘处刀位点密集、刀轴矢量变化剧烈而导致的过切等问题,本文提出了一种带缘头避让的叶片高效螺旋加工方法。在叶片螺旋加工中,只有叶盆和叶背曲面参与切削,缘头曲面从螺旋加工过程剥离并对其实施单独处理。为实现螺旋加工中缘头部分的避让,本文利用三次非均匀B样条曲线给出了避让曲线的构造方法。切削实验结果表明,本文方法可有效提高航空发动机叶片的加工效率,并能有效保证缘头处的加工质量。