深度学习框架下数控机床运动误差溯因方法

为了快速准确地识别数控机床误差因素,提出了一种基于深度学习框架的运动误差智能溯因方法。首先,建立数控机床圆运动误差轨迹基准圆模型,生成理论样本解决深度学习大数据训练问题;然后,基于深度学习目标检测框架,提出数控机床运动误差溯因模型,构建深度卷积网络层自动提取圆运动轨迹特征,改进候选区域生成机制实现轨迹判别及区域生成;最后,模型的区域识别层准确识别误差轨迹类型,通过圆运动轨迹与误差源的映射关系实现对运动误差快速准确智能溯因。实验表明,本文方法可行且适应性好,识别溯源准确,正确率超过96%。     

轴心轨迹自动识别及其在旋机诊断中的应用

提出了一种基于Zernike不变矩特征和神经网络分类器的轴心轨迹自动识别方法.通过对原始Zernike矩特征进行二次提取和处理,获得了对轴心轨迹识别更为敏感的矩特征量,降低了后续神经网络分类器设计的难度.仿真研究表明,基于Zernike矩的轴心轨迹识别方法,其识别精度优于常用的几何矩方法.将所提方法应用于汽轮发电机组和高速离心压缩机组轴心轨迹的自动识别,并结合频谱能量分布特征进行故障诊断,结果表明,引入轴心轨迹特征可以有效地提高旋转机械故障诊断的精度.     

运动助力机械臂轨迹跟踪误差校正方法

运动助力机械臂的轨迹跟踪控制是实现高精度工作的关键。由于运动助力机械臂参数存在的不确定性等因素，导致运动助力机械臂轨迹跟踪误差较高，为此，提出了运动助力机械臂轨迹跟踪误差校正方法。分析运动助力机械臂空间位置和变换关系，根据运动助力机械臂关节与连杆之间的空间坐标矩阵变换过程，构建齐次坐标变换矩阵，获取机械臂末端执行器的空间位姿矩阵。通过定义机械臂轨迹的相关性特征集，得到机械臂轨迹跟踪误差的校正指标。基于置信概率计算，确定机械臂轨迹跟踪误差校正的约束范围，构建约束参量分析模型。采用遗传算法的原理，求解运动助力机械臂轨迹跟踪误差校正参数，实现运动助力机械臂轨迹跟踪误差校正。实验结果表明，所提方法的运动助力机械臂轨迹跟踪误差校正效果较好，能够有效提高运动助力机械臂轨迹跟踪误差校正精度。     

神经网络在数控机床运动误差补偿中的应用

本文利用神经网络建立数控机床圆轨迹运动误差的数学模型，并用神经网络模型输出对数控机床圆轨迹运动误差进行补偿。     

加工中心圆轮廓误差的研究

首先从理论上分析了数控机床加工圆轨迹时所产生的轮廓误差;然后基于平面正交光栅KGM182精密测量系统,研究了在不同的半径和进给速度下的圆运动误差轨迹,得到了一些重要的结论,可以用来指导实际加工。     

数控机床径向运动误差的形成机理及补偿方法研究

研究数控机床圆周插补运动径向误差的形成机理,并提出一种误差软件补偿方法。分别用圆轨迹运动误差测试仪和圆度仪测出数控机床圆周插补运动的径向误差,对该误差建立计算机误差补偿模型,应用该模型进行软件补偿实验研究。实验结果验证了误差形成机理的分析,同时表明提出的误差软件补偿方法能有效地提高数控机床的圆轨迹精度。     

冗余度机械臂零初始关节速度的运动规划方案研究

对一种基于伪逆的冗余度机械臂的运动规划方案进行研究。首先,根据机械臂结构和末端运动规划问题,建立速度层的运动学伪逆算法求解模型。其次,通过在关节速度上加约束,可实现关节速度从零开始平滑变化,并能快速趋近其最小范数解。再次,利用了位置误差补偿方法改善了运动学方程,有效消除或减小机械臂执行任务期间末端执行器的位置误差,保证轨迹跟踪的精度。最后,利用MATLAB软件对平面四连杆机械臂跟踪圆形和螺旋线曲线轨迹进行了仿真实验。仿真结果表明,该运动规划方案具有指数收敛性质,运动误差能达到较高的精度等级。     

数控机床圆运动误差检测与分析

对数控机床的圆运动进行检测,分析了数控机床的各单项误差所引起的典型圆运动误差轨迹,并与实验进行对比.单项误差包括滚珠丝杠与螺母之间的间隙、滚珠丝杠的螺距误差以及控制系统的伺服响应滞后等.     

圆轨迹运动误差测试仪的研制及其应用

本文介绍了一种新型的圆轨迹运动误差测试仪，该仪器具有检测精度高，使用方便的特点。论点涉及仪器的检测原理。结构和应用实例。该仪器为三座标测量机、数控机床等设备的圆轨迹运动误差的动态检测提供了新的重要手段。     

冗余机器人的任务优先级轨迹规划方法

当机械臂末端沿期望轨迹运动时,若障碍物影响机械臂末端运动,则末端会与障碍物发生冲突,使其偏离期望运动轨迹。针对这一问题,提出了一种任务优先级轨迹规划方法,使机械臂末端避障后能够继续跟踪期望轨迹。当机械臂末端运动轨迹中含有障碍物时,赋予避障运动作为优先控制,通过计算末端位置增量使机械臂末端产生逃离速度,进而避开障碍物;反之,赋予轨迹跟踪作为优先控制,通过对机械臂期望轨迹与实际位置进行误差控制,达到提高末端轨迹跟踪精度的目的。最后,对冗余机器人进行了仿真及试验验证。结果表明,当障碍物与机械臂末端运动轨迹发生冲突时,基于任务优先级的轨迹规划方法可以使机械臂末端有效地避开障碍物,同时,末端避障后机械臂仍能跟踪到期望轨迹运动。     

数控机床的运动精度诊断——评述与对策

评述了国内外有关数控机床运动精度测试、诊断与补偿方法的研究情况。在硬件方面分析比较了７种方法；在软件方面分析比较了日本垣野、韩国Ｓ．Ｗ．Ｈｏｎｇ、Ｈ．Ｋ．Ｐａｈｋ、中国台湾Ｊ．Ｍ．Ｌａｉ、浙江大学、天津大学等有关运动误差源建模与识别、多体法误差补偿技术等的研究。指出为提高数控机床的开动率和运行质量，必须走检测—诊断—补偿的途径，先把机床调整到最佳状态，使状态误差尽可能小后再去补偿。提出并介绍了名为“三圆（检测诊断控制）法”的对策。     

二维球杆仪测量装置的研制

提出一种用于测量数控机床圆运动轨迹误差的新装置———二维球杆仪 ,讨论了该仪器的误差分析和补偿。理论分析和测量试验证明 ,该仪器不仅可以测量圆轨迹点的径向误差 ,而且可以测量角度误差。     

Motion error compensation of multi-legged walking robots

Existing errors in the structure and kinematic parameters of multi-legged walking robots,the motion trajectory of robot will diverge from the ideal sports requirements in movement.Since the existing error compensation is usually used for control compensation of manipulator arm,the error compensation of multi-legged robots has seldom been explored.In order to reduce the kinematic error of robots,a motion error compensation method based on the feedforward for multi-legged mobile robots is proposed to improve motion precision of a mobile robot.The locus error of a robot body is measured,when robot moves along a given track.Error of driven joint variables is obtained by error calculation model in terms of the locus error of robot body.Error value is used to compensate driven joint variables and modify control model of robot,which can drive the robots following control model modified.The model of the relation between robot’s locus errors and kinematic variables errors is set up to achieve the kinematic error compensation.On the basis of the inverse kinematics of a multi-legged walking robot,the relation between error of the motion trajectory and driven joint variables of robots is discussed.Moreover,the equation set is obtained,which expresses relation among error of driven joint variables,structure parameters and error of robot’s locus.Take MiniQuad as an example,when the robot MiniQuad moves following beeline tread,motion error compensation is studied.The actual locus errors of the robot body are measured before and after compensation in the test.According to the test,variations of the actual coordinate value of the robot centroid in x-direction and z-direction are reduced more than one time.The kinematic errors of robot body are reduced effectively by the use of the motion error compensation method based on the feedforward.     

基于角域振动信号特征统计量的发动机故障分类方法

为了提高发动机故障分类的准确率和成功率,提出了基于角域信号特征统计量的发动机故障分类方法。包括：利用编码器进行发动机振动信号的等角度采样;采用小波包分析和相关系数法获取发动机角域信号的特征阶次;选取特征阶次信号的能量比、标准差比、谱能量比及谱均值比4组参数作为角域信号特征统计量来提取发动机故障特征;采用支持向量机法对发动机故障进行分类。连杆轴承配合间隙故障的台架试验结果证明:相比于传统的分类方法,该方法明显提高了发动机故障分类的准确率。     

并联轴直线运动直线度的检测与误差补偿

通过采用Renishaw激光干涉仪检测混联机床并联轴直线运动的直线度误差,对直线度的干涉测量原理和方法进行深入探讨,提出一种并联轴直线运动直线度的干涉测量方法和误差补偿模型的建模方法。分析干涉仪直线度评定方法和算法,做出并联轴直线运动直线度双向平均偏差特性曲线,建立直线度误差数学模型。利用最小二乘法拟合得到直线度均值误差补偿模型。对并联轴直线运动直线度进行补偿,达到了提高混联机床几何精度的目的。     

NC机床运动误差的矢量分析法

提出了数控机床圆弧插补运动误差的矢量分析方法。可用双球规测量装置测得数控机床圆弧插补运动的综合误差。在分析运动误差与误差矢量关系的基础上以几种典型误差为例，从理论上提出了单一误差源数学模型的建立方法，给出了与单一误差源所对应的误差特征曲线。用这些数学模型和特征曲线可以诊断出数控机床圆弧插补误差产生的原因。     

数控机床主轴径向运动误差在线高精度检测

数控机床加工工件时，在切削力的作用下，用“以被加工工件为测量基准”的测量方案，实时测量机床主轴的径向运动误差．为了提高信噪比，采用基于精确重构的小波变换算法去除加工时存在的噪声．这种新算法成功地应用于自行开发的在线检测装置中。为了掌握测量系统频域特征，还从谐波抑制和总体频域特性两方面做了分析。通过实验验证了该方法的正确性。     

Evaluation of the form errors of axisymmetric components

The form errors of three-dimensional surfaces have an effect on the proper functioning of an assembly. Methods for evaluating form errors of surfaces of spherical and cylindrical components are available. However, in most machines and instruments the functional components are axisymmetric, e.g. spindles, and have varying geometry in the form of steps, tapers etc. Evaluation of the form errors at different zones on the component as well as a form error characteristic of the whole component is required in such cases. To do this coordinate data or circularity traces are obtained at different horizontal sections using a coordinate measuring machine or a roundness measuring instrument respectively and the required form error is then evaluated. Different algorithms developed for fitting the axis of the component which is the first step in the evaluation of form errors are described. The method of normal least-squares fitting was found to be superior to the general least-squares method.     

A control strategy with motion smoothness and machining precision for multi-axis coordinated motion CNC machine tools

The advanced manufacture technology requires that multi-axis coordinated motion computer numerical control (CNC) machine tools have the capability of high smoothness and high precision. At present, the study of the motion smoothness mainly concentrates on the acceleration and deceleration control method and the look-ahead process of velocity planning in the interpolation stage. The control strategy of the contouring error mainly focuses on tracking error control, cross-coupling control, and optimal control. In order to improve the motion smoothness and contouring precision for multi-axis high-speed CNC machine tools, a multi-axis modified generalized predictive control approach was presented in this paper. In the control strategy, the estimation models of tracking error, contouring error, velocity error, and acceleration error were structured separately. A new improved quadratic performance index was proposed to guarantee the minimum of these errors. Generalize predictive control was also introduced, a multi-axis generalized predictive control model was deduced for motion smoothness and machining precision for multi-axis coordinated motion CNC system, and an approved multi-axis generalized predictive controller based on the model was designed in this paper. The proposed predicted control approach was evaluated by simulation and experiment of circular, noncircular, and space line trajectories, respectively. These simulative and experimental results demonstrated that the proposed control strategy can significantly improve the motion smoothness and contouring precision. Therefore, the new position control method can be used for the servo control system of multi-axis coordinated motion CNC system, which increases motion smoothness and machining precision of CNC machine tools.