Laser triangulation sensor and six axes anthropomorphic robot manipulator modelling for the measurement of complex geometry products

A laser triangulation sensor and six-axis manipulator mathematical modeling for the measurement of complex geometry parts will be outlined in the article. The integrated system model is showed covering the laser triangulation sensor, the geometry of the manipulator and the relative positions of the components during the measurement process. The method to calibrate the sensor and relate the positions of the sensor and the robot is explained in this work. The measurement process is carried out with the parameters calculated with this method and the nominal parameters of the robot. Finally, plane surfaces with holes and termination of tubes placed in different orientations will be measured; the accuracy of the integrated system (sensor and robot) will be presented as well.     

Modelling and calibration of the laser beam-scanning triangulation measurement system

We present an approach of modelling and calibration of an active laser beam-scanning triangulation measurement system. The system works with the pattern of two-dimensional beam-scanning illumination and one-dimensional slit-scanning detection with a photo-multiplier tube instead of a CCD camera. By modelling the system-fixed coordinate, we describe the formulation of 3D computation and propose a calibration method in terms of LSE using a planar fitting algorithm. As a sensor-dependent solution, the estimation is refined in the domain of sensing variables. Result of calibration of the real system and a brief analysis of systematic errors are given.     

An automatic measurement system for the wall thickness of corrugated plate based on laser triangulation method

Wall thickness is an important parameter used in the characterization of the surface quality of chevron corrugated plates. However, current measurement techniques such as contact mechanical or destructive modes are timing-consuming and are limited by the complex morphology of the measured object. In this study, an optical measurement system is established for experimental evaluation of the wall thickness. Its optical design and working characteristic are described based on the triangulation principle. By performing normal vector estimation, and combining with the search results about the best possible reconstructed mesh surface, the wall thickness at each measurement point can be evaluated. A series of comparison experiments with the maximum deviation 0.043 mm show that our proposed method can provide effective and automatic technical support for dimensional detection of complex components.     

基于CMOS激光位移传感器的板厚测量系统

为了提高板材厚度参数的测量效率和精度,本系统利用CMOS激光位移传感器,通过激光三角法实现板材厚度的测量,并利用MPC08运动控制卡控制交流伺服系统实现激光位移传感器的测量定位,同时计算机对采集数据进行分析处理、显示和存储.实验表明该系统运行稳定可靠,测量效率大幅提高.     

基于光源扫描的三角法位移测量方法

对激光三角法测量位移的几种光路布局方案及其特点进行了比较,在此基础上,提出了一种新的基于光源扫描的三角法激光位移测量方法,阐述了激光三角法测量原理,并设计了相应的测量系统,分析了影响系统精度的因素。理论分析可知,该系统的测量分辨力可达到1.5×10-5m。实验结果表明:此系统有很强的实用性,测量范围为0mm~10m,适用于工业生产。     

MEMS传感器的惯性测量模块的设计与初始校准

设计了一种基于微机电系统(MEMS)传感器的惯性测量模块,它包括三轴加速度计、三轴陀螺和三轴磁阻传感器。这种惯性测量模块具有体积小、功耗低、成本低的优点,可以方便地用在微小机器人定位系统以及空中机器人控制系统中。详细分析了模块的误差来源,提出了模块中三轴加速度计的非正交误差模型。并运用基于Newton迭代的方法实现了一种自动初始校准算法。实验结果表明:这种自动初始校准算法可以有效地消除该模块的固定偏差、比例误差和非正交误差。     

一种新的无陀螺惯性测量组合标定方法

无陀螺惯性测量组合在角速率解算过程中不仅需要知道加速度计标定因数、零偏及实际安装方向向量,还需要准确获取加速度计的实际安装位置.针对上述特点,以加速度计输出模型为基础,提出并建立了一种广泛适用于各种无陀螺惯性测量组合的标定方法.该方法经转台位置和速率实验验证可以准确得到加速度计标度因数、零偏及安装误差,进一步提高了载体线加速度和角速率解算精度,从而为后续的姿态解算奠定基础.     

数字气压传感器的一种高效标定和补偿方法

硅压阻式压力传感器受制造工艺和测量环境的影响,其输出大都具有一定的非线性,其中以温度的影响最为明显。鉴于此,传感器需要准确地标定测试和温度补偿,首先制作一种带有高精度AD和微处理器的数字气压传感器,用它采集数据;然后分析测试设备,确定采用恒压变温的标定方案,它不仅效率高,而且能准确反映传感器的温度和输出特性;最后用最小二乘算法在微处理器上实现温度补偿,补偿后传感器的输出精度满足了应用需求。     

三基色测温法在CCD图像传感器测温中的应用

设计了CCD图像传感器的非接触式测温系统,对三基色测温法进行了介绍,并应用三基色测温法对采集的某固体火箭发动机的高温燃气舵图像进行了温度场仿真计算,并对比了CCD比色测温法和三基色测温法,结果表明本文提出的测温法能有效地测量出高温燃气舵表面温度场,提高了测温精度。     

基于CAE仿真和矩阵标定的汽车零部件载荷测试方法

针对结构形状及受载复杂的汽车零部件的载荷测试,采用矩阵标定方法进行载荷测试.根据CAE应力仿真结果确定应变贴片位置并利用CAE方法模拟试验矩阵标定过程,确定可行的试验矩阵标定方案;开展试验矩阵标定和路谱采集,得到试验标定矩阵和应变历程并计算零部件的载荷.以某款汽车后悬架拖曳臂标定为例阐述标定过程,并验证该方法可行.该方法能提升复杂零部件的载荷测试、动力学载荷分解和疲劳试验精度.     

基于精密星敏感器的航天器高精度姿态测量标定方法

为了解决传统航天器姿态测量方法中存在的误差率高的问题,提出基于精密星敏感器的航天器高精度姿态测量标定方法。首先对使用的精密星敏感器进行设计,并将在不影响航天器运行的前提下安装在合适的位置上。通过建立运动坐标系、坐标参数转换和设置姿态参数三个步骤得出航天器运动模型,在该模型下分析出航天器姿态的基本运动规律、利用精密星敏感器识别并选取航天器空间下的任意三个星点,最后综合定位的星点和航天器姿态的运动规律,从不同的角度上确定航天器姿态测量结果,为了提高航天器姿态测量结果的精度进行标定处理。通过模拟实验分析得出结论：与传统测量方法相比,基于精密星敏感器的航天器高精度姿态测量标定方法的平均误差率降低了6.0%。     

一种用于位移测量装置校准的LVDT模拟器

为了实现位移测量装置的自动化校准,根据线性可调差动变压器(LVDT)的工作原理,提出了一种基于D/A转换器的LVDT模拟器的设计思想。该模拟器以LVDT主线圈交流激励信号作为参考电压,利用参考电压和数字给定值的乘积关系,通过改变D/A的数字量得到幅值可变的LVDT副线圈输出电压,从而模拟铁心位置改变时LVDT副边信号的变化关系。试验表明:该模拟器具有0.024%的稳态精度和200Hz的动态带宽,可以高度逼真地模拟LVDT电气行为,完全满足LVDT类位移测量装置的维护和校准需要。相对于采用实际LVDT,利用该模拟器进行校准可省去高精度的运动机构,可以提供更大的灵活性,并可以实现校准过程自动化。     

A new calibration method for an inertial and visual sensing system

The relative pose between inertial and visual sensors equipped in autonomous robots is calibrated in two steps. In the first step, the sensing system is moved along a line, the orientations in the relative pose are computed from at least five corresponding points in the two images captured before and after the movement. In the second step, the translation parameters in the relative pose are obtained with at least two corresponding points in the two images captured before and after one step motion. Experiments are conducted to verify the effectiveness of the proposed method.     

A method for the calibration of a 3-D laser scanner

The calibration of a three-dimensional digitizer is a very important issue to take into consideration that good quality, reliability, accuracy and high repeatability are the features which a good digitizer is expected to have. The aim of this paper is to propose a new method for the calibration of a 3-D laser scanner, mainly for robotic applications. The acquisition system consists of a laser emitter and a webcam with fixed relative positions. In addition, a cylindrical lens is provided with the laser housing so that it is capable to project a plane light. An optical filter was also used in order to segment the laser stripe from the rest of the scene. For the calibration procedure it was used a digital micrometer that move a target with known dimensions. The calibration method is based on the modeling of the geometrical relationship between the 3-D coordinates of the laser stripe on the target and its digital coordinates in the image plane. By this method it is possible to calibrate the intrinsic parameters of the video system, the position of the image plane and the laser plane in a given frame, all in the same time.     

基于激光位移传感器的小转角测量方法研究

针对结构刚度测试中的转角测量问题,提出了一种新的小转角测量方法。采用激光位移传感器测量待测物体的切向线位移值,再通过几何关系将其转换成转角值。建立了包含4个因素的误差数学模型,分析了±1°的测量范围内各误差因素分别对测量结果的影响,结果表明：光斑距刻线标志偏距Δl对误差的影响较大。应用本方法,针对一异形构件进行了扭转刚度测试,当Δl上下限为±1 mm时,测量误差在2%左右,验证了本方法的有效性和准确性。     

加速度传感器动态校准系统不确定度评估方法的研究

针对加速度传感器动态校准获取其工作频带的过程中,因校准系统存在测试不确定度导致传感器校准不准确的问题,设计了某型号加速度传感器的动态校准试验,以试验数据为依据提出了系统不确定度评估方法。通过对冲击试验台为冲击激励源构成的动态校准系统测试过程中几个主要误差源的分析,结合文中提出的系统不确定度评估方法计算出校准系统的测试标准不确定为1.77%,扩展不确定度为3.54%。对比测量仪器特性评定相关指标可知该校准系统符合工程校准需要,而该评估方法的提出对校准系统的不确定度评估有一定的现实指导意义。     

A robot hand-eye calibration method of line laser sensor based on 3D reconstruction

In the robotic eye-in-hand measurement system, a hand-eye calibration method is essential. From the perspective of 3D reconstruction, this paper first analyzes the influence of the line laser sensor hand-eye calibration error on the 3D reconstructed point clouds error. Based on this, considering the influence of line laser sensor measurement errors and the need for high efficiency and convenience in robotic manufacturing systems, this paper proposes a 3D reconstruction-based robot line laser hand-eye calibration method. In this method, combined with the point cloud registration technique, the newly defined error-index more intuitively reflects the calibration result than traditional methods. To raise the performance of the calibration algorithm, a Particle Swarm Optimization - Gaussian Process (PSO-GP) method is adopted to improve the efficiency of the calibration. The experiments show that the Root Mean Square Error (RMSE) of the reconstructed point cloud can reach 0.1256 mm when using the proposed method, and the reprojection error is superior to those using traditional hand-eye calibration methods.     

基于图像的树木测量方法

树木是城市绿化、美化的一个重要的组成部分,具有重要的科学、历史和观赏价值。传统的树木生长信息采集方式,利用人工使用卷尺或不易操作、低效率和复杂麻烦的大型测量仪器等,费时、费力、准确度又不高。结合计算机视觉、数学几何模型等技术,设计了一种新式的树木高度、胸径和冠幅测量模型,提出了基于图像的树木测量方法和实现了树木信息采集软件系统;为了得到更精确的测量结果,使用摄像头标定技术和坐标校正方法对图像进行畸变矫正;并且利用正交试验分析法分析本设计使用的最佳拍摄环境,最终相对误差控制在4%左右。本方法具有携带方便、操作简单、适用面广、准确度高的优势。     

一种自动校准多风表的风洞检测试验装置

针对传统风表校准方式需多次手动调节风量、操作复杂、人工读数与绘图费时费力且校准精度低等问题,设计了一种自动校准多风表的风洞检测试验装置,介绍了该装置的结构及检测试验原理。试验结果表明,该装置风流稳定,可自动调节风量,操作简单,可1次校准多个风表,校准精度高,并能对校准结果进行记录、存储、处理,适合于低、中、高3档多风表自动校准。     

Using infrared sensors for distance measurement in mobile robots

The amplitude response of infrared (IR) sensors based on reflected amplitude of the surrounding objects is non-linear and depends on the reflectance characteristics of the object surface. As a result, the main use of IR sensors in robotics is for obstacle avoidance. Nevertheless, their inherently fast response is very attractive for enhancing the real-time operation of a mobile robot in, for instance, map building tasks. Thus, it seems that the development of new low-cost IR sensors able to accurately measure distances with reduced response times is worth researching. In this paper, a new IR sensor based on the light intensity back-scattered from objects and able to measure distances of up to 1 m is described. Also, the sensor model is described and the expected errors in distance estimates are analysed and modelled. Finally, the experimental results obtained are discussed.