基于MEMS和CORTEX-M3的微惯性测量单元研制

从工程实际出发,给出了一种基于新型Cortex-M3内核ARM和MEMS惯性传感器的低成本、高性能微型惯性测量单元的结构框架。详细介绍了采用三轴MEMS陀螺、三轴MEMS加速度计和三轴磁阻传感器研制的微惯性测量单元硬件设计方案,分析了陀螺和加速度计的信号噪声,利用均值滤波法对信号进行预处理,对预处理后的信号采用FIR滤波器进行滤波,对陀螺和加速度计进行了标定。该测量单元已应用于某小型无人机的姿态测量,达到预期效果。     

A new tunneling-based sensor for inertial rotation ratemeasurements

Microelectromechanical (MEM) technology promises to significantly reduce the size, weight, and cost of a variety of sensor systems. For vehicular and tactical-grade inertial navigation systems, high-performance MEM gyroscopes are required with 1-100°/h resolution and stability. To date, this goal has proven difficult to achieve in manufacturing for many of the previous approaches using Coriolis-based devices due, in part, to the need to precisely tune the drive and sense resonant frequencies. We have designed, fabricated, and tested a new highly miniaturized tunneling-based sensor that employs the high displacement sensitivity of quantum tunneling to obtain the desired resolution without the need for precise mechanical frequency matching. Our first tested devices with 300-μm-long cantilevers have demonstrated 27°/h/√Hz noise floors. Measurements indicate that this number can be reduced to near the thermal noise floor of 3°/h/√Hz when a closed-loop servo, operating at the device's oscillation frequency, is implemented around the sensor     

基于采煤机工作面端头量测的改进因子图高精度自主定位方法

采煤机的高精度定位是煤炭开采自动化和智能化的重要研究方向,其中惯性导航系统和里程计是长壁综合机械化采煤机定位主要传感器之一.通过两者的信息融合,能够有效抑制惯性导航系统的发散并且具有较好的自主导航能力,但是仍然无法满足井下长时间的高精度导航要求.鉴于此,分析目前常用辅助传感器在采煤机开采过程中存在的问题,提出基于UWB采煤机工作面端头量测的改进因子图优化方法.利用UWB在工作面端头的位置量测信息,推导并构建惯导/里程计/UWB的约束方程和图优化模型.同时通过惯性信息的预积分,减少待优化的节点数量,降低算法的计算量.在此基础上,加入里程计标度因数误差和安装误差的因子节点进行联合估计和优化.最后通过仿真和实际跑车测试表明,相较于传统卡尔曼滤波的采煤机定位方式,所提出方法能够有效提高采煤机的定位精度.     

GPS盲区三维定位技术的研究

研究基于MEMS的加速度传感器的原理,对组合导航系统的工作原理和关键技术进行分析。采用惯性导航算法获得三维移动的位移,并且结合GPS系统定位,研制出GPS盲区内移动目标的三维定位终端;实现了GPS盲区的较高精度和可靠性的三维移动物体定位,有较好的容错性和环境适应性,具有实际使用价值。     

SENSORDYNAMICS新一代微机电陀螺仪和惯性组合传感器

奥地利SensorDynamics公司是一家汽车用微机电陀螺仪和惯性组合传感器的专业生产商,产品主要用于汽车防侧翻系统和电子稳定系统.目前SD公司凭借其QFN封装的陀螺仪和惯性系统系列进人非汽车应用市场,其代表性产品是大小仅为6x6x1.2mm的全集成六自由度惯性测置单元6DoF-IMU,目标市场包括导航系统、稳定平台...     

Effect of thermal and mechanical properties variations on microcantilever mass sensor performance

Ensuring desirable performance for piezoelectric microcantilever sensors constitutes a crucial research subject particularly for the applications such as detection of biochemical entities, virus particles or human biomarkers. However, these sensors’ performance may be affected by the environmental conditions such as temperature variation, and/or the uncertainty in the material properties. The objective of this study is to explore Young modulus uncertainty of microcantilever’s structural layer, thermo-mechanical and geometrical temperature dependency effects, on the natural frequency, bias and sensitivity of microcantilever mass sensors. These effects have been investigated for different sensor lengths and resonant modes. Also, a temperature compensation method which omits the need for bulky non-contact thermometers or fabrication of built-in temperature sensor has been proposed. As theoretical model, Euler–Bernoulli beam theory has been employed and solved by Galerkin expansion procedure. Using this model, it is demonstrated that the sensitivity of microcantilever sensor decreases with increasing the added mass. The microcantilever sensor sensitivity operating at the second resonant mode has been improved almost five times comparing to the first mode sensitivity regardless of microcantilever length. The simulation results show that temperature variation causes thermal frequency shift which in turn introduces a significant mass bias far beyond the sensors’ minimum detectable mass. This mass bias is constant for a given microcantilever in its first and second resonant mode. Additionally, the effect of temperature variation on the sensitivity of the given mass sensors is negligible. However, it has been shown that the variations in sensors sensitivity due to uncertainty of Young modulus remain constant for different lengths and two resonant modes of the microcantilever sensor.     

一种微惯性测量单元标定补偿方法

在介绍微惯性测量单元组成与结构的基础上,根据MEMS惯性器件的输出特性,建立了微惯性测量单元中加速度计和陀螺仪的数学标定模型,提出并推导了一种适用于微惯性测量单元的标定方法,该方法可以得到微惯性测量单元中惯性传感器的零位、标度因数、安装误差系数及g值敏感项等33个参数;然后,具体介绍了通过加速度计重力场静态翻滚试验和陀螺仪恒角速率试验对MIMU中参数标定的方法和步骤,并对实验室自研的MIMU进行了标定;最后利用得到的标定参数对测试结果进行了误差分析与补偿;实验结果表明,该方法使MIMU的测量精度提高了1～2个数量级,能够满足姿态解算及导航计算的精度要求。     

Error Analysis and Stochastic Modeling of Low-cost MEMS Accelerometer

This paper presents the error analysis and stochastic modeling of commercial low-cost MEMS Accelerometer. Although Micro Electro Mechanical Systems (MEMS) based sensors have been utilized for the development of low-cost integrated navigation systems on the benefits of low inherent cost, small size, low power consumption, and solid reliability, it is significantly important to characterize the error behaviors of MEMS-based sensors and to construct more sophisticated mathematical modeling methods. The errors of MEMS-based accelerometer have been identified into deterministic and stochastic error sources and the stochastic error part was the focus to be discussed in this paper using discrete parameter models of stationary random process. Appropriate Autoregressive (AR) models have been analyzed which can be used to help the development of appropriate optimal algorithm for multiple sensor integration.     

四轮全向小车的惯性传感装置的设计

四轮全向小车因其载荷平稳和全向驱动的运动方向灵活而被广泛地应用于高性能机器人小车。为提高四轮全向小车的运动性能,设计了一套以DSP为CPU,由MENS加速度传感器、陀螺仪和电子罗盘组成的惯性传感装置。该装置体积小,价格低,结构简单,实时性好,能很好地实现小车的加速度、姿态角和角加速度的测量。此外该装置还通过小车电机的光电编码器实现里程计,以便在其后的研究中实现小车的惯性导航。     

Navigation Aided Image Processing in UAV Surveillance: Preliminary Results and Design of an Airborne Experimental System

This paper describes an airborne reconfigurable measurement system being developed at Swedish Defence Research Agency (FOI), Sensor Technology, Sweden. An image processing oriented sensor management architecture for UAV (unmanned aerial vehicles) IR/EO-surveillance is presented. Some preliminary results of navigation aided image processing in UAV applications are demonstrated, such as SLAM (simultaneous localization and mapping), structure from motion and geolocation, target tracking, and detection of moving objects. The design goal of the measurement system is to emulate a UAV-mounted sensor gimbal using a stand-alone system. The minimal configuration of the system consists of a gyro-stabilized gimbal with IR and CCD sensors and an integrated high-performance navigation system. The navigation system combines dGPS real-time kinematics (RTK) data with data from an inertial measurement unit (IMU) mounted with reference to the optical sensors. The gimbal is to be used as an experimental georeferenced sensor platform, using a choice of carriers, to produce military relevant image sequences for studies of image processing and sensor control on moving surveillance and reconnaissance platforms. Furthermore, a high resolution synthetic environment, developed for sensor simulations in the visual and infrared wavelengths, is presented. © 2004 Wiley Periodicals, Inc.     

Robust real-time tracking by fusing measurements from inertial and vision sensors

The problem of estimating and predicting position and orientation (pose) of a camera is approached by fusing measurements from inertial sensors (accelerometers and rate gyroscopes) and vision. The sensor fusion approach described in this contribution is based on non-linear filtering of these complementary sensors. This way, accurate and robust pose estimates are available for the primary purpose of augmented reality applications, but with the secondary effect of reducing computation time and improving the performance in vision processing. A real-time implementation of a multi-rate extended Kalman filter is described, using a dynamic model with 22 states, where 12.5 Hz correspondences from vision and 100 Hz inertial measurements are processed. An example where an industrial robot is used to move the sensor unit is presented. The advantage with this configuration is that it provides ground truth for the pose, allowing for objective performance evaluation. The results show that we obtain an absolute accuracy of 2 cm in position and 1° in orientation.     

基于ADS8568的八路数据采集系统设计

为了提高某惯性测量单元的精度,需对其输出信号进行大量采集以建立误差模型.该惯性测量单元不仅包含6路惯性传感器信号(3路陀螺和3路加速度计),还包括两路温度传感器输出以提供温度补偿,所以设计了基于ADS8568的八路数据采集系统.该系统采用AD芯片ADS8568,实现8路模拟信号的同步采集;以FPGA为主控芯片,控制信号的采集存储;以8G bit FLASH为存储芯片,实现大容量数据的实时存储.经实验验证,该采集系统可以正确采集传感器输出数据,采集到的数据正确有效,可用于误差建模的分析,具有一定的工程实用价值.     

Control of temperature fields of a strapdown inertial navigation system based on fiber optic gyroscopes

Theoretical and applied issues of creating a reversible control system of time-variant temperature fields of fiber optic gyroscopes and a strapdown inertial navigation system based on such gyroscopes are considered. Mathematical models of thermal processes in the fiber optic gyroscopes and a strapdown inertial navigation system with an active double-loop reversible temperature control system based on thermoelectric coolers are constructed. Software is developed, parameters of the temperature control system are selected, computational experiments are performed, and estimates of the operation of the corresponding dynamic systems under complex thermal conditions are obtained.     

Validation of nonlinear integrated navigation solutions

There exist numerous navigation solutions already implemented into various navigation systems. Depending on the vehicle in which the navigation system is used, it can be distinguished in most cases among; navigation, tactical, and commercial grade categories of such systems. The core of these systems is formed by inertial sensors, i.e. accelerometers and angular rate sensors/gyros. Navigation and tactical grade systems commonly rely on fiber optic/ring laser gyros and servo/quartz accelerometers with high resolution, sensitivity, and stability. In the case of cost-effective navigation systems, for example piloted light and ultralight aircraft, usually use commercial grade sensors, where the situation differs. The sensor outputs are less stable and sensitive, and suffer from manufacturing limits leading to temperature dependency, bias instability, and misalignment which introduces non-negligible disturbances. These conditions commonly limit the applicability of the navigation solution since its stand-alone operation using free integration of accelerations and angular rates is not stable. This paper addresses a cost-effective solution with commercial grade inertial sensors, and studies the performance of different approaches to obtain navigation solution with robustness to GNSS outages. A main goal of this paper is thus comparison of a nonlinear observer and two extended Kalman filter solutions with respect to the accuracy of estimated quantities and their sensitivity to GNSS outages. The performance analyses are carried out on real flight data and evaluated during phases of the flight when the solutions are challenged by different environmental disturbances.     

基于MEMS加速度传感器的步数检测算法研究综述

随着智能移动终端、智能穿戴设备以及基于惯性传感器的行人定位导航系统的快速发展,针对这些设备和系统中的计步需求,大量有关基于MEMS加速度传感器的步数检测算法的研究工作已经开展并取得了优秀的成果。针对该领域中现有的技术方法,首先阐述了该领域的发展情况,指出目前该领域的主要研究要点、方法种类以及应用情况。接着,综述了目前该领域的研究现状,从数据预处理方法和步数验证方法这两方面对多种步数检测算法进行了阐述以及优缺点的分析。然后,对该领域的研究要点进行了深入的探讨,分析总结步数检测算法中与研究要点相关的技术方法。最后,讨论并展望了该领域未来的发展方向,以期为后续的研究提供参考。     

Determination of exposure to engineered carbon nanoparticles using a self-sensing piezoresistive silicon cantilever sensor

A novel MEMS-based cantilever sensor with slender geometry is designed and fabricated to be implemented for determining personal exposure to carbon engineered nanoparticles (NPs). The function principle of the sensor is detecting the cumulative mass of NPs deposited on the cantilever surface as a shift in its resonant frequency. A self-sensing method with an integrated full Wheatstone bridge on the cantilever as a piezoresistive strain gauge is introduced for signal readout replacing optical sensing method. For trapping NPs to the cantilever surface, an electrostatic field is used. The calculated equivalent mass-induced resonant frequency shift due to NPs sampling is measured to be 11.78?±?0.01?ng. The proposed sensor exhibits a mass sensitivity of 8.33?Hz/ng, a quality factor of 1,230.68?±?78.67, and a temperature coefficient of the resonant frequency (TC _f ) of ?28.6?ppm/°C. These results and analysis indicate that miniaturized sensors based on self-sensing piezoresistive microcantilever can offer the performance to fulfill the requirements of real-time monitoring of NPs-exposed personnel.     

轮式移动机器人组合导航方法及试验研究

该文提出了以惯性导航为基础,磁感应器修正的移动机器人组合导航方法。该方法以陀螺仪、磁感应器和里程计作为导航信息的检测器件,每隔一定的距离,利用磁感应器检测到的信息对陀螺仪和里程计进行修正,使得移动机器人能够精确定位、长时间稳定运行。一方面,消除了纯惯性导航随时间增长累积的误差;另一方面,对外界环境有较强的抗干扰能力。试验结果验证了该组合导航方法是有效、可行的,适于在线实时应用,能融合其它导航传感器信息,具有较强可扩展性。     

A high integrity navigation architecture for outdoor autonomous vehicles

This paper describes the design of a high integrity navigation system for use in large autonomous mobile vehicles. A frequency domain model of sensor contributions to navigation system performance is used to study the performance of a conventional navigation loop. On the basis of this, a new navigation system structure is introduced which is capable of detecting faults in any combination of navigation sensors. A decentralised architecture is also presented for the fusion of information from different asynchronous sources. An example implementation of these principles is described which employs a twin GPS/inertial navigation system and a millimeter wave radar/encoder navigation loop.     

IMU标定数学建模及误差分析

惯性测量单元（IMU）标定路径设计和数据处理方法取决于IMU标定数学模型,安装误差是决定IMU标定模型的重要因素。针对工程中加速度计和陀螺相对载体安装方式的不同,提出一种通过坐标系转换矩阵建立IMU标定数学模型的方法,推导IMU标定模型误差与载体角速度和加速度之间的关系,分析IMU标定模型误差对捷联惯性导航系统导航参数的影响,并利用转台提供的位置信息设计IMU标定路径和数据处理方法。仿真和转台实验结果表明：IMU标定数学模型误差引起捷联惯性导航系统速度误差、位置误差和姿态误差;安装误差的表现形式决定了IMU标定模型误差对系统导航精度的影响。     

Enhanced sensing characteristics in MEMS-based formaldehyde gas sensors

This paper presents a novel micro fabrication for formaldehyde gas sensors to enhance sensitivity and detection resolution capabilities. Therefore, two different types of fabrication sequences of gas sensors were considered, different positions of micro heaters and sensing layers to compare the effects of different areas of the sensing layers contact with the surrounding gas. The MEMS-based formaldehyde gas sensor consists of a quartz substrate, a thin-film NiO/Al₂O₃ sensing layer, an integrated Pt micro-hotplate, and Pt inter-digitized electrodes (IDEs) to measure the resistance variation of sensing layers caused by formaldehyde oxidation at the oxide surface. This abstract offers comparisons of the characteristics of sensors in different areas of the sensing layers contacting the surrounding gas as well as those to decrease the thickness of the sensing layer and deposits of the sensing layer using co-sputtering technology with NiO/Al₂O₃ to improve the sensitivity limits of the sensors. The experimental data indicated that increasing the area of the sensing layer that contacts with the surrounding gas and decreasing the thickness of the sensing layer in the sputtering process and then co-sputtered NiO/Al₂O₃ sensing layers, significantly enhanced the sensing characteristics of the developed formaldehyde sensor.