基于AHRS和物联网的智能倾角仪的研制

介绍了一种可进行空间全角度测量、具有高度互联性的倾角仪的研制方法,实现了对远程、大动态等运动设备倾角的在线测量和分析。该倾角仪硬件上采用惯性MEMS传感器组成的AHRS(航姿参考系统),并用卡尔曼滤波进行数据融合解算角度,通过蓝牙4. 0和android移动终端进行数据交换和后端处理,为测量仪器的智能化和物联化发展提供参考。     

基于椭球拟合的MEMS倾角仪现场快速标定系统

针对由倾角仪核心模块MEMS加速度计的偏值和标度因数会随时间推移而产生变化,造成倾角仪倾角测量误差变大、准确度降低、对精密标定设备依赖性强的问题,设计一种基于STM32结合椭球拟合算法的倾角仪现场快速标定系统。该系统以STM32单片机为核心处理单元,内嵌椭球拟合算法,修正MEMS加速度计的偏值和标度因数;配合自编程的上位机程序实现对倾角仪的现场快速标定,保证其测量准确度。试验结果表明:该倾角仪现场快速标定系统操作方便,标定后降低测量误差且使测量准确度提高一个量级,具有一定的工程应用价值。     

基于六自由度运动轨迹的晃车仪测试技术北大核心CSCD

针对现有晃车仪测试方法单一,难以满足实际工况要求,以及晃车仪内部单一加速度传感器在线角复合振动下解算不确定度大的问题,基于六自由度平台,利用其复合运动的轨迹,采用与陀螺仪传感器数据融合的方法测量复合振动角度幅值。通过量化处理线角复合振动,利用陀螺仪测量振动角度幅值,校正复合振动下单一加速度传感器受到的倾角影响,以提高晃车仪解算精度,并对融合解算后的参考频率点进行扩展不确定度评定。结果表明陀螺仪与晃车仪二者数据融合后整个测试系统线振动和角振动相对扩展不确定度分别为0.36%、0.08%,拓宽了晃车仪标准测试工况。     

激光跟踪仪测角精度评定方法

本文以Leica AT901＿B激光跟踪仪为测试仪器,进行测角精度的评定研究。由于缺乏严密的角度检校标准,本文参考经纬仪／全站仪系统检校规范,提出以常规的角度检校模型为基础,采用全圆方向观测法获取数据,通过坐标反算观测值来计算系统轴系误差2C值和I角误差,并通过最小二乘平差原理解算系统水平角误差和垂直角误差。该方法基于严密的经纬仪／全站仪角度检校模型,真实地反映了激光跟踪仪的轴系误差和测角精度。通过数据的平差解算,求得AT901＿B的水平和垂直测角精度分别为0．54″和0．52″,由此评定出AT901＿B激光跟踪仪的实测精度符合其标称精度。     

基于修正EKF的微小型飞行器姿态估计

分析了常用飞行姿态估计方法在微小型飞行器上应用的局限性,针对基于微机电系统(MEMS)惯性器件的姿态测量方案,构建了以MEMS陀螺仪姿态矩阵解算为状态更新、以MEMS加速度计重力矢量解算为观测更新的扩展卡尔曼滤波器(EKF),推导了相应的卡尔曼滤波方程.为了提高该滤波器抵抗机动加速度干扰的能力,设计了基于M估计的新息修...     

基于四元数和Kalman滤波器的多传感器数据融合算法

工业现场、工程计量的倾角测量要求测量范围大、测量精度高。本文采用四元数进行姿态变换,Kalman滤波器进行数据融合,在低成本的ARM平台和MEMS传感器上实现了多传感器数据融合算法,解算出空间全角度的姿态角。实验结果表明测量误差在±0. 2°范围内,能够满足一定范围内的测量要求。     

独立卡尔曼滤波器全加速度计复杂振动角速度解算

对于运动体的多自由度振动测试,准确的振动角速度是复杂振动参数解算的关键。针对目前解算角速度单一方法测试精度不理想的问题,分析由4个三轴加速度计组成传感器阵列,测试角速度解算算法,设计一种独立的卡尔曼滤波器用于角速度解算。通过仿真及实验证明:该方法解算结果的误差最大值和标准差相对于单一方法可提高1个数量级,其得到的角速度幅值准确性和曲线平滑度也优于其他单一解算方法。     

用正弦规校准数显倾角仪示值误差的不确定度

数显倾角仪是进行角度测量常用的计量器具,为保证倾角仪计量性能的准确可靠,利用正弦规对其进行角度测量.文章重点介绍了该校准方法和示值误差的不确定度评定.     

基于MEMS陀螺的压气机静子叶片安装角度测量系统研究

介绍了一种基于MEMS陀螺的高精度压气机静子叶片安装角度测量系统的设计方案。从测量需求入手,利用双轴MEMS陀螺角度传感器和基准工装对小空间、高精度的静子叶片安装角进行测量,推导了倾角测量算法,进行了误差分析,并设计了基于MEMS陀螺的角度测量系统。     

基于倾角仪测试铁路桥梁静态挠度

桥梁挠度测量是桥梁检测的重要组成部分和安全性评价的一项重要指标。随着铁路桥梁设计跨度逐步增大、桥梁主跨下面为江流等因素,传统的静态挠度测试法如水准仪等不再适合测试大跨度桥梁的静态挠度,该文利用QY倾角仪测量了焦柳铁路线上的融水大桥第3跨的静态挠度。测试结果表明:倾角仪测得的静态挠度值与水准仪测得值相差较小,其挠度曲线也相似于有限元分析所得挠度曲线,可适用于大跨度铁路桥梁的静态挠度测试。     

Highly Accurate Inclinometer Robust to Ultralow-Frequency Acceleration Disturbances and Applications to Autotracking Antenna Systems for Vessels

This paper describes a new inclinometer that compensates for ultralow-frequency acceleration disturbances. This inclinometer consists of a low-cost accelerometer, pendulum, and rotary encoder. The key feature of this inclinometer is the estimation method used to calculate the pendulum's inertial angle. We propose two algorithms to estimate the pendulum's angle. Algorithm I uses time-averaged accelerations and some assumptions. Algorithm II applies the pendulum's equation of motion. The results of simulations and experiments confirm that both algorithms can achieve highly accurate level/angle estimations under acceleration disturbance conditions. We apply this inclinometer to an autotracking antenna system for vessels. Time simulations verify its effectiveness.      

Bi-dimensional fluid inclinometer

A gravity referenced optical inclinometer which uses a transparent fluid as angle-sensor element is described. Its principle of operation is based on light refraction at a free surface of the fluid. Measurements were carried out in an optical inclinometer built by the authors, and a resolution of 0.007° was obtained. The inclinometer permits real-time angle determinations along two perpendicular axis.     

High Precision Robust Automatic Alignment Method for Rotating Shaft

Rotating Shaft is widely used in various high precision instruments on scientific and industrial metrology. This paper proposes a high precision and robust method to automatically align a rotating shaft perpendicular to the horizontal plane. Firstly, an alignment model consisting of a dual-axis inclinometer and four motors is designed. Then the rotating shaft tilt angle between the practical and the ideal shaft is projected to two orthogonal planes, and generates a rotation angle in each plane. The two rotation angles are calculated by differential measurement method based on the inclinometer outputs, and then the relationship of shaft tilt angle against inclinometer outputs is obtained. According to these two rotation angles, the relative heights of the three supporting points of the platform attached to the rotating shaft are calculated. Employing an angle closed loop strategy; the rotating shaft tilt angle is aligned by three linear stepping motors. Experiment results show an alignment precision of 0.003º is achieved using an inclinometer with the resolution of 0.0005º and a linear stepping motor with the regulation precision of 0.89 μm. The proposed method is suitable for a wide variety of precision machines that require the use of rotating shaft.     

Research on horizontal displacement monitoring of deep soil based on a distributed optical fibre sensor

The traditional measurement method for the horizontal displacement of deep soil usually uses an inclinometer for piecewise measurement and then generates an artificial reading, which takes a long time and often contains errors; in addition, the anti-jamming and long-term stability of the inclinometer is poor. In this paper, a technique for monitoring horizontal displacement based on distributed optical fibres is introduced. The relationship between the strain and the deflection was described by a theoretical model, and the strain distribution of the inclinometer tube was measured by the cables laid on its surface so that the deflection of the inclinometer tube could be calculated by the difference algorithm and regarded as the horizontal displacement of deep soil. The horizontal displacement monitoring technology of deep soil based on distributed optical fibre sensors developed in this paper not only overcame the shortcomings of traditional inclinometer technology to realize automatic real-time monitoring but also allowed for distributed measurement. The experiment was similar to the expected engineering situations, and the deflection calculated from the strain was compared with an inclinometer. The results demonstrated that the relative error between the distributed optical fibre sensors and the inclinometer was less than 8.0%, and the results also verified both the feasibility of using distributed optical fibre to monitor the horizontal displacement of soil as well as the rationality of the theoretical model and difference algorithm. The application of distributed optical fibre in monitoring the horizontal displacement of deep soil in the engineering of foundation pits and slopes can more accurately evaluate the safety of engineering during construction.     

IS-48 inclinometric system

A comparative analysis of a series-produced control and measurement instrument, the IN 1-721 continuous-action inclinometer, with the recently developed IF-60 ferromagnetic-sonde inclinometer and the IS-48 inclinometric system is presented. The layout of the down-hole logging instrument and the structure of the IS-48, an instrument that maintains serial signal sampling, are considered. Multi-level correction of the instrumental errors which eliminates traditional adjustment procedures is described. Results of down-hole logging tests are presented. Translated from Izmeritel'naya Tekhnika, No. 8, pp. 29–32, August, 1997.     

车载光电跟踪设备高精度控制方法及仿真

介绍了保证车载光电跟踪设备高精度工作的一种数学方法,在光电跟踪设备基座上安放双轴倾角传感器,实时检测基座的水平度,通过传感器显示的数值,把基座的水平度变化量解算到光电跟踪设备的水平轴和垂直轴上去。构建所需的数学模型,分析工作原理,求出了光电跟踪设备水平轴和垂直轴所需转动角度的公式。建立CAD模型,并结合有虚拟样机技术对模型进行仿真分析。有限元分析表明：这种数学方法可以保证车载光电跟踪设备的工作精度。     

A Ferrofluidic Inclinometer in the Resonant Configuration

In this paper, an innovative inclinometer exploiting ferrofluids is presented. The device consists of a glass pipe filled with deionized water and a drop of ferrofluid, a coil generating a retaining force on the ferrofluidic drop, a couple of sensing coils detecting the ferrofluidic mass position, and two exciter coils moving the ferrofluidic drop back and forth inside the water at the resonance frequency of the whole system. The device exhibits an intrinsic robustness against inertial shocks. The resonant operation mode represents the main novelty with respect to previous realizations of the ferrofluidic inclinometer presented by the authors. This strategy allows for improving the performances of the inclinometer also in terms of mechanical sensitivity. This paper will focus on the design and experimental characterization of the resonant inclinometer, showing improvements achieved by the resonant configuration with respect to the previous “static implementation” without the exciter coils.      

Deformation within polar ice sheets: An analysis of the Byrd Station and Camp Century borehole-tilting measurements

Analysis of the inclinometer surveys of the boreholes at Byrd Station, Antarctica, and Camp Century, Greenland, yields the following results. The measured strain rates at both stations, in ice deposited in the last (Wisconsin) glaciation, reduced to a standard temperature and shear stress, are only about one-third those in the Holocene ice, even though the Wisconsin ice has a strong single-maximum fabric. Variations in strain rate in the Wisconsin ice at Byrd Station are negatively correlated with the number of volcanic dust bands in the ice. It is inferred that the ice below 1800 m at Byrd Station, which has a multiple-maximum fabric, deforms much less readily than the remainder of the ice. A flow model of Nye, with index n = 3, provides a relation between shear strain rate and shear stress that fits the data from both stations satisfactorily, even though the assumption of plane strain is not strictly valid at Byrd Station. A value of flow parameter A fifteen to twenty times that given by recent data compilations and predicted by dislocation theory, has to be used for the Holocene ice. These data cover a stress range (20–45 kPa) lower than in any other field experiment.     

Dual-axis thermal convective inclinometer based on CNT/PDMS composite

This paper presents the design, fabrication, and characterization of a novel inclination-angle sensor (inclinometer) using heating and sensing elements based on conductive polydimethylsiloxane (PDMS) composited with carbon nanotubes (CNTs). The inclinometer consists of a PDMS cube-shaped chamber, a CNTs/PDMS composite-based heater, and four CNTs/PDMS composite-based temperature sensors. The working mechanism of this sensor is based on thermal convective sensing theory on the basis of the detection of thermal disturbance caused by inclination-induced convection in a sealed chamber. In order to prepare the conductive CNTs/PDMS composite, toluene was applied as a solvent to facilitate CNT dispersion in PDMS matrix and then was removed by evaporation. The resistive heating and thermal sensing properties of CNT/PDMS composite-based elements were tested and analyzed first. Then, the responses to inclination-angle were monitored and reported. Experimental results demonstrate that the inclinometer can measure dual-axis angular position in the range of 360° with high stability and repeatability.