MULTIPLE ELECTRONIC CONTROL UNITS CALIBRATION SYSTEM BASED ON EXPLICIT CALIBRATION PROTOCOL AND J1939 PROTOCOL

The rising number of electronic control units （ECUs） in vehicles and the decreasing time to market have led to the need for advanced methods of calibration. A multi-ECU calibration system was developed based on the explicit calibration protocol （XCP） and J1939 communication protocol to satisfy the need of calibrating multiple ECUs simultaneously. The messages in the controller area network （CAN） are defined in the J1939 protocol. Each CAN node can get its own calibration messages and information from other ECUs, and block other messages by qualifying the CAN messages with priority, source or destination address. The data field of the calibration message is designed with the XCP, with CAN acting as the transport layer. The calibration sessions are setup with the event-triggered XCP driver in the master node and the responding XCP driver in the slave nodes. Mirroring calibration variables from ROM to RAM enables the user to calibrate ECUs online. The application example shows that the multi-ECU calibration system can calibrate multiple ECUs simultaneously, and the main program can also accomplish its calculation and send commands to the actuators in time. By the multi-ECU calibration system, the calibration effort and time can be reduced and the variables in ECU can get a better match with the variables of other ECUs.

Establishment of a calibration curve for an isocentric cobalt unit using Monte Carlo simulation

Measurement of dose distribution in patients during radiotherapy is impossible. The Monte Carlo simulation is an alternative method for dose calculations. In routine radiotherapy, the source-to-surface distance(SSD)method is not practical for an isocentric unit because it requires numerous values of tissue–air ratios and inverse square law. Therefore, this method is time consuming. In this paper, the curves of relative depth doses were obtained for three different SSDs using the MCNP4C Monte Carlo simulation and approximated with a single curve called calibration curve. This curve was compared to the curve obtained by published data, differing in approximately 5% in the worst case. It was also observed that the obtained results were more accurate for distances between-5 and 10 cm from source-to-axis distance.

Design of Automatic Batch Calibration and Correction System for IMU

Thanks to its light weight,low power consumption,and low price,the inertial measurement units(IMUs)have been widely used in civil and military applications such as autopilot,robotics,and tactical weapons.The calibration is an essential procedure before the IMU is put in use,which is generally used to estimate the error parameters such as the bias,installation error,scale factor of the IMU.Currently,the manual one-by-one calibration is still the mostly used manner,which is low in efficiency,time-consuming,and easy to introduce mis-operation.Aiming at this issue,this paper designs an automatic batch calibration method for a set of IMUs.The designed automatic calibration master controller can control the turntable and the data acquisition system at the same time.Each data acquisition front-end can complete data acquisition of eight IMUs one time.And various scenarios of experimental tests have been carried out to validate the proposed design,such as the multi-position tests,the rate tests and swaying tests.The results illustrate the reliability of each function module and the feasibility automatic batch calibration.Compared with the traditional calibration method,the proposed design can reduce errors caused by the manual calibration and greatly improve the efficiency of IMU calibration.

Monocular Visual-Inertial and Robotic-Arm Calibration in a Unifying Framework

Reliable and accurate calibration for camera,inertial measurement unit(IMU)and robot is a critical prerequisite for visual-inertial based robot pose estimation and surrounding environment perception.However,traditional calibrations suffer inaccuracy and inconsistency.To address these problems,this paper proposes a monocular visual-inertial and robotic-arm calibration in a unifying framework.In our method,the spatial relationship is geometrically correlated between the sensing units and robotic arm.The decoupled estimations on rotation and translation could reduce the coupled errors during the optimization.Additionally,the robotic calibration moving trajectory has been designed in a spiral pattern that enables full excitations on 6 DOF motions repeatably and consistently.The calibration has been evaluated on our developed platform.In the experiments,the calibration achieves the accuracy with rotation and translation RMSEs less than 0.7°and 0.01 m,respectively.The comparisons with state-of-the-art results prove our calibration consistency,accuracy and effectiveness.

基于PE-ANGO的MIMU现场标定方法

针对当前微惯性测量单元(MIMU)的现场标定方法存在标定步骤复杂、不利于非专业人员操作等问题,提出了一种基于先验知识增强的自适应北苍鹰优化(PE-ANGO)算法的MIMU现场标定方法。首先分析了MIMU涉及的误差并建立了加速度计和陀螺仪的目标函数,然后使用PE-ANGO算法求解目标函数并得到最优参数。为了使得标定工作易于现场操作,引入了一种用于传感器数据采集的手持MIMU来验证所提算法。仿真结果表明:PE-ANGO算法的标定精度相较于北苍鹰优化算法提高了一个数量级。实测实验表明:标定前后对俯仰角和横滚角累积误差的抑制效果分别提高了约89%和87%;与传统标定方法相比,对俯仰角和横滚角累积误差的抑制效果分别提高了71%和68%,验证了所提方法的有效性。

一种考虑g敏感性的MIMU系统级标定方法研究

针对微机械惯性测量单元(micro-electro-mechanical-system inertial measurement unit,MIMU)中存在陀螺漂移的g敏感性以及因漂移误差大而无法进行自主方位对准问题,建立了MIMU系统级标定Kalman滤波状态空间模型,考虑g敏感性误差状态的影响,在量测方程中加入方位失准角变化率以增强g敏感性的状态估计可观性;直接采用外输入粗略初始方位角进行导航解算,降低地球自转角速度的影响,提高陀螺漂移估计精度。设计了一套完整的系统级标定转位编排方案,陀螺标定和加速度计标定相互依赖,共同协作完成MIMU系统级标定,能够有效分离出所有30个标定参数,利用某型号弹载MIMU进行了实物标定试验验证,分别用标定前后数据进行导航解算,对比导航结算结果发现标定后的3个方向的导航速度都降低了,加速度计的刻度因数和零偏标定精度更高。特别在MIMU存在多轴大角度转动情况下,近10 min内达到优于30 m/s的导航速度精度,验证了系统级标定具有较高的精度。

Hg-CEMS烟气预处理关键问题研究与进展

鉴于汞在化石燃料和矿物资源中的天然禀赋以及能源与资源利用过程中汞污染物的排放与监管,研发我国自主知识产权的汞连续在线监测系统(Hg-CEMS)成为汞排放浓度监测的国家重大需求。烟气预处理技术是Hg-CEMS系统中最关键的组成部分,也是限制我国Hg-CEMS技术发展与应用的核心技术。对Hg-CEMS烟气预处理技术中的4个关键模块——稀释采样模块、Hg0/Hg^(2+)分离模块、Hg^(2+)还原模块、Hg^(2+)标气发生模块的研究进展进行全面综述。首先,介绍稀释采样技术的原理与应用,阐述音速小孔和热稀释引射器的结构和设计要点,论述数值模拟与优化设计相结合的方法。其次,针对Hg0/Hg^(2+)分离技术,综述湿法吸收、物理吸附和化学吸附的研究新进展,讨论选择性吸附剂KCl和CaO的理论和实验研究结果。第3,针对Hg^(2+)还原技术,概述湿化学还原、低温还原和高温分解还原的技术,论证低温还原技术中固态还原剂的活性成分、反应温度以及烟气成分对氧化态汞还原的影响,探讨高温分解还原技术中填充材料、酸性气体组分以及除酸剂对Hg^(2+)还原和抑制Hg0再氧化的新研究进展。最后,针对Hg^(2+)标气发生技术面临的技术难点,提出固态标气发生新技术理念并指出其工业应用的可行性。结合当前Hg-CEMS技术的研究发展和应用现状,提出上述4个关键模块的研究思路、解决方案与应用前景。

基于改进LSTM网络的无人机MEMS-IMU零偏在线标定方法

针对在卫星信号拒止、视觉系统退化场景中无人机MEMS-IMU零偏无法准确估计并补偿导致导航误差迅速发散的问题,提出一种基于改进长短时记忆(LSTM)网络的零偏在线标定方法。首先,为解决MEMS-IMU零偏数据非线性强、传统循环时间网络训练效果差的问题,设计序列到序列的LSTM神经网络结构,引入教师强迫机制,提高了网络特征学习能力。然后,在导航过程中使用训练后的网络对MEMS-IMU零偏在线标定,补偿后的IMU量测与视觉信息联合优化,保证了导航定位精度。实验结果表明,在纯惯性导航实验中,所提方法的绝对位置误差比传统LSTM方法减小了6.5%;在EUROC数据集下进行的视觉惯性组合导航实验中,所提方法的平均绝对位置误差比传统LSTM方法减小了15%。

一种十表冗余激光陀螺捷联惯组标定方法研究

针对十表冗余激光陀螺三自捷联惯组(包含5只陀螺和5只加速度计)的标定问题,推导给出了标定模型以及标定方案。将十表冗余惯组划分为直表X\Y\Z和斜表S\T两组,直表采用系统级标定方法,建立关于标定误差模型的状态方程,以导航速度误差作为量测,通过Kalman滤波估计标定误差参数;以直表标定结果作为参考,进行斜表的分立式标定,分别建立了加速度计、陀螺标度系数和陀螺漂移的标定模型。最后,结合19位置系统级标定方法和分立式标定方法完成了十表冗余激光捷联惯组标定,结果显示标定结果正确,分析了标定误差特性。

150万t/a常减压装置标定数据分析

基于某石化厂150万t/a常减压装置的生产现状,连续进行了为期3 d的标定,主要考核装置的实际生产能力,各项参数是否达到设计规定的指标,考核加热炉运行能力、常减压塔的分离能力和产品质量情况以及装置的能量消耗、能耗分布情况等。通过标定分析摸清装置运行情况和不利因素,为进一步优化操作参数提供基础数据,为装置处理量的提高、技术改造、节能降耗等措施提供技术依据。

变风量空调系统的风量平衡调试

变风量末端装置(VAV BOX)是变风量空调系统的核心组成部分。本文借助于楼宇自控系统(BAS)对装有压力无关型单风道VAV BOX的变风量空调系统的单机风量调试及风管系统平衡调试作了介绍。VAV BOX的单机风量调试主要是VAV BOX的风量标定,风管系统平衡调试主要是各手动风阀的开度调试。

一种密度继电器的全自动在线校验方式

提出了一种密度继电器全自动在线校验方法,通过调压装置控制对气体的压缩升压过程,并对继电器报警及闭锁时的模拟量信号进行精准采集,数据处理单元根据内置采样气体的温度特性曲线,将采集到的模拟信号转换为既定温度的标准压力值,与实际气体的压力对比后,自动调节以实现采样气体的动态补偿。经反复实践验证,此种方法不仅能够实现对密度继电器的精确校验,更达到了提升电网运维智能化水平的目标。

某型惯组系统级标定算法研究与应用

针对某型惯性测量单元高精度惯性参数输出需求,提出并实现了一种基于卡尔曼滤波的系统级标定算法。首先,在建立标定坐标系的基础上,分析了系统级标定误差模型,并对双轴转台标定方案设计及算法实现进行了论述。其次,进行了系统级标定全温试验并对标定结果进行了分析,最终在完成标定补偿的基础上进行了标定参数一致性验证和导航性能验证。试验结果表明,与传统标定方案相比,该系统级标定方案不受减振垫影响,无需北向基准,实现简单方便,可一次标定出惯性测量单元主要误差参数,重复性高、参数一致性好,具有良好的工程应用价值。

旋锁载荷称重系统研究

为解决岸边集装箱起重机传统测量方法响应慢、精度差、可靠性低、易损坏的问题,提出一种基于旋锁称重的集装箱起重机载荷监测系统。旋锁载荷称重系统由测力单元、数据处理器及系统内通信总线、司机室报警显示单元、系统对外通信总线和数据存储单元组成,用于监测集装箱起重机吊具的起吊质量,将测力单元的传感器集成在集装箱起重机的旋锁内。该系统具有响应快、精度高、可靠性高、不易损坏等优点,同时可以实时监测、显示吊具每个旋锁上的载荷,并将质量数据存储起来。在监测到旋锁载荷异常时,系统可以迅速进行声光报警,或直接锁定吊具驱动电机,阻止非正常起吊,预防事故发生,提升集装箱起重机的安全性。此外,采用旋锁载荷称重系统可以保障提升机构的钢丝绳不会因过重而出现变形和损坏,进一步提升岸边集装箱起重机的安全性。

高压直流电场非接触测量传感器的设计与研究

电力运营商应定期维护和检修直流设备,确保直流输电系统的安全生产和应用。在设备维护时,必须检测直流设备是否带电,是否超过电场强度安全阈值,以保证操作人员的寿命和设备的安全。本文采用非接触法测量高压直流电场。基于电容式传感器原理,研制了一种自反馈低功耗直流电场传感器。通过反馈调整传感器的范围和灵敏度。通过优化直流电场传感单元结构参数的设计,得出当感应电流信号幅值最大时,感应电极扇形叶片开度叶数为n=6。屏蔽电极与传感电极之间的距离d=3 mm。传感电极采用差分信号输出,抑制共模信号的干扰。传感器标定实验表明,该范围为±65 kV/m,灵敏度系数65.6,精度0.5 kV/m,测量误差小于2%。传感器在内部具有良好的一致性和可靠性±40 kV/m。该传感器不仅可以用于测量高压直流电场的强度,而且在航空航天和气象雷电研究中,具有广阔的应用前景。

A Calibrating Device for Rogowski Coil Development

A calibrating device for the Rogowski coil is developed, which can be used to calibrate the Rogowski coil having a partial response time within tens of nanoseconds. Its key component is a step current generator, which can generate the output with a rise time of less than 2 ns and a duration of larger than 300 ns. The step current generator is composed by a pulse forming line （PFL） and a pulse transmission line （PTL）. A TEM （transverse electromagnetic mode） coaxial measurement unit is used as PTL, and the coil to be calibrated and the referenced standard Rogowski coil can be fixed in the unit. The effect of the dimensions of the TEM unit is discussed theoretically as well as experimentally.

基于无人船的多波束系统水下地形测量应用

为解决多波束测深过程中测区水域租用船只难、水下测深单元安装校准步骤繁琐、测量船难以严格按照预设航线航行等问题,开展了基于多波束测深技术和无人船技术的水下地形测量研究。简要介绍了多波束系统的主要组成部分、工作原理,分析了将多波束系统与无人船技术相结合并应用在水下地形测量中的诸多优势及其关键技术,在湖北省巴东县链子溪进行了将多波束测深系统搭载于无人船上的工程实践。结果表明,多波束测深技术与无人船技术的结合应用,简化了测深设备安装校准流程,提高了作业效率。

LiDAR标签和栅格占有图结合的LiDAR/IMU空间标定方法

LiDAR和惯性测量单元(inertial measurement unit,IMU)在智能汽车获得了广泛的应用,比如高精度地图构建、车辆实时定位等。两种传感器进行组合测量时,需要知道两者之间的空间关系,包括空间旋转和平移参数。本文提出了一种基于LiDAR标签的自动化LiDAR/IMU空间标定方法。首先分析了LiDAR/IMU标定参数对LiDAR点云拼接的影响,证明了当车辆近似直线运动时,使用概略标定参数即可利用IMU的姿态信息将LiDAR点云转换到轴向近乎一致的坐标系。基于该结论,提出了一种基于IMU姿态约束的LiDAR栅格占有图构建方法,构建高相对精度的点云地图与LiDAR标签的点云进行地图匹配,获得LiDAR标签在图中的位置,相对于单点云帧互匹配方法,提高标签点云匹配的精度和可靠性。然后基于LiDAR标签的已知高精度位置,采用非线性优化方法解算栅格占有图与LiDAR标签的空间转换关系,进而求解LiDAR/IMU的空间标定参数。试验结果表明,利用本文方法获得的标定参数构建的点云地图,可实现厘米级的绝对位置精度,验证了本文方法的正确性和可行性。

一种考虑加表不对称误差的冗余惯组标定方法

使用冗余惯性器件的捷联惯组有效地提高了其可靠性,还能提高导航精度,但也同时对其标定技术提出了新的要求。提出了一种迭代式的冗余惯组分立标定方法,可消除加表不对称误差对标定造成的影响,提高标定精度。首先建立了基于方向余弦的惯性器件输入输出模型,用最优估计方法计算模型中各参数。其次,使用迭代方法消除由于加表刻度因数不对称造成的参数估计误差,且所提方法无需北向基准。试验结果证明,在整个5100 s的动态导航中使用所提方法后,全程位置精度均有所提升,并能将末端位置精度提升约400 m。

Design of on-board calibration methods for a digital sun sensor based on Levenberg–Marquardt algorithm and Kalman filters

Digital sun sensor is one of the most important sensors used in the Attitude Determination System(ADS)of the satellite.Due to the harsh environmental conditions that exist in the space,various distortions may occur in the sun sensor optical system that lead to the reduced accuracy of this equipment.So,it is necessary to recalibrate the optical parameters of the aforementioned sensors.For this purpose,first a novel attitude independent error model is proposed for the SS-411 sun sensor that includes the central point of the CCD array,installation error,filter thickness and sensor misalignment.So,the mutual interfaces between the sensor parameters are considered in the developed model.In order to extract the sensor parameters,a nonlinear optimization technique called the Levenberg–Marquardt is applied to the developed model as a batch algorithm.In addition,the Extended Kalman Filter(EKF)and the Unscented Kalman Filter(UKF)have been utilized as sequential strategies.It will be shown that by considering a worst case of variation amount for sensor parameters,an accuracy improvement of about 17°is achieved by the developed calibration algorithms.Comparison between the developed algorithms represents that UKF has higher accuracy,shorter time convergence but higher computational load.