一种新的直线度测量方法

本文介绍了一种新直线度测量方法,运用该方法对一长直导轨进行了直线度测量。实验表明:利用PSD、激光器、A/D及计算机等组成的检测系统具有自动化程度高、测量速度快、安装调试简单等优点。该系统尤其适用于长件直线度的批量检测。     

激光束角漂移对频激光直线度测量的影响

利用惠更斯关于波面传播的理论，分析计算了双频激光渥拉斯顿棱镜直线度测量系统中激光束角漂移以及渥拉斯顿棱镜和双面反射镜倾角对测量精度的影响，得到了相应的结论。     

激光束角漂移对双频激光直线度测量的影响

利用惠更斯关于波面传播的理论，分析计算了双频激光渥拉斯顿棱镜直线度测量系统中激光束角漂移以及渥拉斯顿棱镜和双面反射镜倾角对测量精度的影响，得到了相应的结论。     

一种新型平尺直线度自动测量方法

阐述了按JJF 1097—2003《平尺校准规范》推荐的传统方法(桥板法)对平尺直线度测量存在的缺点,同时提出了一种采用光电自准直仪自动检测平尺直线度的方法,并分析比较了桥板法和光电自准直仪法检测平尺直线度的误差计算方法,最后总结出光电自准直仪法利用目前先进的仪器及计算机软件自动采集数据、无线传输、自动平差等技术,可大大减少人为误差,节省人力物力,所测数据准确可靠.     

轴线直线度误差的一种近似评定方法

本文提出一种近似评定圆柱形工件轴线直线度误差的方法，该方法利用两个传感器在万能工具显微镜上测得工件被测点的二维坐标，利用一种简便的近似评定法获得了工件直线度误差，该方法简单实用，适于在工厂及实验室测量及评定轴线直线度误差。     

轴线直线度误差的一种近似评定方法

本文提出一种近似评定圆柱形工件轴线直线度误差的方法．该方祛利用两个传感器在万能工具显微镜上测得工件被测点的二维坐标．利甩一种简便的近似评定法获得工件轴线直线度误差，该方法简单实用，适于在工厂及实验室测量及评定轴线直线度误差。     

一种圆管类工件直线度激光测量系统

设计了一种圆管类工件直线度激光测量系统,提出了一整套关于圆管类工件定心、内径获取和直线度计算的方法。研制了高精度的自动定心机构,采用双锥体同轴定心法实现测量系统在圆管类工件内的高精度自动定心。通过位置敏感探测器(PSD)和准直激光获得圆管各截面中心坐标,结合旋转扫描机构获得圆管内径测量值,并采用最小二乘椭圆拟合算法进行定心误差修正,最后进行数据处理,计算出工件直线度。实验结果表明,该系统定心准确度可达20μm,内径测量准确度可达5μm,测量重复性稳定在7μm以内,直线度测量准确度在40μm以内。     

一种新型平尺直线度自动测量的方法

比较桥板法测量平尺直线度误差的方法和一种新型的自动测量方法,指出了桥板法测量的缺点,分析了自动测量的检测精度优势和实时采集数据计算优势,并通过实例计算来比较两种测量方法的精度,为平尺直线度误差测量提供了一种创新思路。     

一种应用于光纤陀螺寻北的温度漂移补偿方法

光纤陀螺寻北启动误差是启动过程温度剧烈变化导致的光纤陀螺零偏漂移产生的误差,表现为冷启动时寻北误差较稳定段时明显增大,事实上延长了有效寻北时间。通过对光纤陀螺温度漂移影响因素的分析,利用经验模态分解、ARMA建模与Kalman滤波建立多参量线性模型,实现了一种应用于光纤陀螺寻北的温度漂移补偿方法,实验结果表明,该方法可以将寻北启动误差降低近80%,使得冷启动时寻北精度与稳定段相当并缩短了有效寻北时间。     

共路激光干涉测量系统的研究

激光干涉测量系统在精密测量领域占有重要地位,它对温度变化、大气变化、激光波长变化、机械安装误差和外界振动等比较敏感,影响系统的测量精度和稳定性。针对此情况,该文提出一种新型的激光干涉光路,两光臂呈完全共路结构,使干涉条纹信号具有极强的抗干扰能力;对光路进行抗干扰分析和理论推导;构建位移测量系统,进行系统测试实验和误差分析。实验表明,本系统测量分辨力0.72nm,合成标准不确定度5．2nm（k=2）,运行速度0．56mm／s,量程0．01mm。     

采用小波降噪和神经网络的FOG温度漂移补偿方法

光纤陀螺(FOG)输出易受环境温度的影响,发生漂移导致光纤陀螺测量精度降低。采用传统的BP神经网络容易陷入局部极小值,导致网络训练失败。为了优化BP神经网络,本文提出了一种粒子群(PSO)优化BP神经网络与小波降噪相结合的光纤陀螺温度漂移补偿方法。首先分析了光纤陀螺温度漂移产生的原因;然后在不同温度下对光纤陀螺进行测试,最后采用该方法建立了光纤陀螺温度漂移模型并根据模型对光纤陀螺进行补偿,结果表明采用该方法补偿后光纤陀螺在不同温度下的输出标准差降低了60.19%,与传统的BP神经网络相比补偿效果显著提高。     

Tool path re-planning in free-form surface machining for compensation of process-related errors

Free-form surfaces are widely used in many applications in today’s industry. This paper presents a new approach to identify and compensate process-related errors in machining of free-form surfaces. The process-related errors are identified online by a newly developed in-process inspection technique. In this technique, the surface is first machined through an intermediate semi-finishing process that is specifically designed to machine different geometric shapes on the surface with different process parameters. An inspection method is developed to identify the process-related errors in the selected regions on the semi-finished surface. The relationship between the machining/surface parameters and process-related error is then achieved using a neural network. This relationship is used to predict the process-related errors in the finishing process. The process-related errors, together with the machine tool geometric errors identified using a method developed in our previous work, are compensated in the finishing tool paths through tool path re-planning. Experiment has been conducted to machine a part with a free-form surface to show the improvements in the machining accuracy.     

双光路多通道颜色快速计测系统

介绍一种用于物体色快速测量的双光路多通道系统。     

A real-time filtering method for the drift data of a laser Doppler velocimeter

To effectively reduce the random drift of a laser Doppler velocimeter (LDV), a real-time filtering model is presented for filtering the drift data of an LDV, which is a combination of the metabolic grey model (1, 1) and the metabolic time series model AR (2). The basic principle of the metabolic grey-time series model is introduced in detail first. Then, the model is established for the static and dynamic drift data, and a Kalman filter is used to filter the drift data based on the model. The variance analysis method and the Allan variance method are employed to analyse the static drift data. The dynamic drift data are also compared before and after being modelled and filtered. The results demonstrate that the metabolic grey-time series method cannot only effectively reduce the static random drift of an LDV, but can also reduce the dynamic random drift in real time.     

MCR-NAS: A combined hard-soft multivariate curve resolution method based on net analyte signal concept for modeling kinetic data with inert interference and baseline drift

This paper demonstrates a novel implementation of a net analyte signal (NAS) algorithm for resolving kinetic model. The evaluation of spectroscopic kinetics data by the established hard-modeling approach assumes that all the variation related to the response is linked to the species involved in the kinetic process. If effects are present in the data that cannot be explained by the model, such as baseline drift or inert interference, the estimated rate constant might be incorrect. An iterative net analyte signal procedure is shown to yield good rate constant estimates when the spectroscopic data is influenced by additional sources of variance. Simulated and real examples are used to confirm this statement.     

A general gamma nonlinearity compensation method for structured light measurement with off-the-shelf projector based on unique multi-step phase-shift technology

ABSTRACT

Nonlinearities in the application of fringe projection metrology make it very difficult to acquire perfect 3D data. This paper describes a six-step phase-shifting technique for a structured light measurement system with an off-the-shelf projector. First, the phase error is analysed and a gamma model is established by deriving the relative expression between the wrapped phase and input images. This is then expressed in matrix form to derive a unique solution, which is used for the gamma solver. The complex gamma calibration and projector error compensation can be removed once the gamma value of the off-the-shelf projector has been determined. The ideal model reconstruction results are obtained through simulations and experiments, and the standard deviation of the phase error is found to be only 0.0039 radians. Hence, the proposed method eliminates the nonlinear errors associated with fringe projection technology using existing projectors and improves the overall image reconstruction quality.