Performance Evaluation of Three-Dimensional UWB Real-Time Locating Auto-Positioning System for Fire Rescue

Fire rescue challenges and solutions have evolved from straightfor-ward plane rescue to encompass 3D space due to the rise of high-rise city buildings.Hence,this study facilitates a system with quick and simplified on-site launching and generates real-time location data,enabling fire rescuers to arrive at the intended spot faster and correctly for effective and precise rescue.Auto-positioning with step-by-step instructions is proposed when launching the locating system,while no extra measuring instrument like Total Station(TS)is needed.Real-time location tracking is provided via a 3D space real-time locating system(RTLS)constructed using Ultra-wide Bandwidth technology(UWB),which requires electromagnetic waves to pass through concrete walls.A hybrid weighted least squares with a time difference of arrival(WLS/TDOA)positioning method is proposed to address real path-tracking issues in 3D space and to meet RTLS requirements for quick computing in real-world applications.The 3D WLS/TDOA algorithm is theoretically constructed with the Cramer-Rao lower bound(CRLB).The computing complexity is reduced to the lower bound for embedded hardware to directly compute the time differential of the arriving signals using the time-to-digital converter(TDC).The results of the experiments show that the errors are controlled when the positioning algorithm is applied in various complicated situations to fulfill the requirements of engineering applications.The statistical analysis of the data reveals that the proposed UWB RTLS auto-positioning system can track target tags with an accuracy of 0.20 m.

Performance analysis of real-time and post-mission kinematic precise point positioning in marine environments

This article focuses on the performance analysis of both real-time and post-mission kinematic precise point positioning(PPP)in challenging marine environments.For this purpose,a real dynamic experiment lasting 6 h was carried out on a lake dam in?orum City of Turkey.While the kinematic test was continuing,the real-time PPP coordinates were obtained for each measurement epoch with a commercial real-time PPP(RT-PPP)service,namely the Trimble Center Point RTX.Then the post-mission PPP(PM-PPP)coordinates were calculated by using Multi-GNSS data and the Multi-GNSS Experiment(MGEX)precise products.The kinematic RT-PPP and PM-PPP results showed that the PPP coordinates were consistent with the relative solution at centimetre and decimetre level in horizontal and height components,respectively.This study implies that PPP technique is a powerful tool for highly accurate positioning in both real-time and post-mission modes,even for dynamic applications in harsh environments.

Cross-ocean GPS long distance rapid static positioning methods

The method of cross-ocean GPS long distance rapid static positioning has become one of the main technical means of GPS static positioning away from the mainland. The key technology had been analyzed in-cluding data preprocessing and quality control, long distance integer ambiguity resolution and static Kalman filter parameter estimation. Effective data processing method of cross-ocean GPS long baseline rapid static positioning had been proposed. Through the analysis of practical examples of coastal and ocean, the feasibility of cross-ocean GPS long distance rapid static positioning based on the method is testified and verified. The results show that the accuracy of one-hour single baseline static positioning for the 500 - 600 km distance can be better than 10cm in the three-dimensional coordinates ocean environment. , which can suffice static positioning accuracy in the special

A Precision-Positioning Method for a High-Acceleration Low-Load Mechanism Based on Optimal Spatial and Temporal Distribution of Inertial Energy

High-speed and precision positioning are fundamental requirements for high-acceleration low-load mechanisms in integrated circuit （IC） packaging equipment. In this paper, we derive the transient nonlinear dynamicresponse equations of high-acceleration mechanisms, which reveal that stiffness, frequency, damping, and driving frequency are the primary factors. Therefore, we propose a new structural optimization and velocity-planning method for the precision positioning of a high-acceleration mechanism based on optimal spatial and temporal distribution of inertial energy. For structural optimization, we first reviewed the commonly flexible multibody dynamic optimization using equivalent static loads method （ESLM）, and then we selected the modified ESLM for optimal spatial distribution of inertial energy; hence, not only the stiffness but also the inertia and frequency of the real modal shapes are considered. For velocity planning, we developed a new velocity-planning method based on nonlinear dynamic-response optimization with varying motion conditions. Our method was verified on a high-acceleration die bonder. The amplitude of residual vibration could be decreased by more than 20% via structural optimization and the positioning time could be reduced by more than 40% via asymmetric variable velocity planning. This method provides an effective theoretical support for the precision positioning of high-acceleration low-load mechanisms.

Quality monitoring of real-time GNSS precise positioning service system

The Real-Time Global Navigation Satellite System(GNSS)Precise Positioning Service(RTPPS)is recognized as the most promising system by providing precise satellite orbit and clock correc-tions for users to achieve centimeter-level positioning with a stand-alone receiver in real-time.Although the products are available with high accuracy almost all the time,they may occasionally suffer from unexpected significant biases,which consequently degrades the positioning perfor-mance.Therefore,quality monitoring at the system-level has become more and more crucial for providing a reliable GNSS service.In this paper,we propose a method for the monitoring of realtime satellite orbit and clock products using a monitoring station network based on the Quality Control(QC)theory.The satellites with possible biases are first detected based on the outliers identified by Precise Point Positioning(PPP)in the monitoring station network.Then,the corresponding orbit and clock parameters with temporal constraints are introduced and esti-mated through the sequential Least Square(LS)estimator and the corresponding Instantaneous User Range Errors(IUREs)can be determined.A quality indicator is calculated based on the IUREs in the monitoring network and compared with a pre-defined threshold.The quality monitoring method is experimentally evaluated by monitoring the real-time orbit and clock products generated by GeoForschungsZentrum(GFZ),Potsdam.The results confirm that the problematic satellites can be detected accurately and effectively with missed detection rate 4×10^(-6) and false alarm rate 1:2×10^(-5).Considering the quality alarms,the PPP results in terms of RMS of positioning differences with respect to the International GNSS Service(IGS)weekly solution in the north,east and up directions can be improved by 12%,10%and 27%,respectively.

Efficient Harmonic Analysis Technique for Prediction of IGS Real-Time Satellite Clock Corrections

Real-time satellite orbit and clock corrections obtained from the broadcast ephemerides can be improved using IGS real-time service (RTS) products. Recent research showed that applying such corrections for broadcast ephemerides can significantly improve the RMS of the estimated coordinates. However, unintentional streaming interruption may happen for many reasons such as software or hardware failure. Streaming interruption, if happened, will cause sudden degradation of the obtained solution if only the broadcast ephemerides are used. A better solution can be obtained in real-time if the predicted part of the ultra-rapid products is used. In this paper, Harmonic analysis technique is used to predict the IGS RTS corrections using historical broadcasted data. It is shown that using the predicted clock corrections improves the RMS of the estimated coordinates by about 72%, 58%, and 72% in latitude, longitude, and height directions, respectively and reduces the 2D and 3D errors by about 80% compared with the predicted part of the IGS ultra-rapid clock corrections.

改良俯卧位通气对急性呼吸窘迫综合征患者呼吸功能及预后的影响

目的 探究改良俯卧位通气对急性呼吸窘迫综合征(ARDS)患者血流动力学、呼吸动力学及预后的影响。方法 前瞻性选取河南大学第一附属医院2020年3月至2022年6月收治的98例ARDS患者作为研究对象,通过随机数字表法分为A、B组。通过随机及前瞻性平行对照临床研究,评价不同通气方式在ARDS患者中的作用,其中A组52例接受改良式俯卧位通气,B组46例接受传统俯卧位通气。对比两组患者干预前、干预后(俯卧位通气4 h后)血流动力学[心率(HR)、平均动脉压、中心静脉压]、呼吸动力学指标[气道阻力、静态肺顺应性(Cst)]、氧合指数及腹腔压力的变化。比较两组患者不良事件发生情况,对所有患者进行3个月随访,比较两组患者病死率情况。结果 (1)A组机械通气时间低于B组,撤机成功率高于B组(P<0.05);(2)干预后,两组患者HR均较干预前上升,干预前后差值具有统计学意义(P<0.05);(3)干预后,两组Cst水平均较干预前上升且A组高于B组,干预前后差值具有统计学意义(P<0.05);(4)干预后,两组腹腔压力均较治疗前上升且A组低于B组,干预前后差值具有统计学意义(P<0.05);(5)A组不良事件总发生率[7.69%(4/52)]低于B组[23.91%(11/46)](P<0.05);(6)随访3个月结果显示,A组病死率[23.08%(12/52)]低于B组[43.48%(20/46)](P<0.05)。结论 改良俯卧位通气对ARDS血流动力学、呼吸动力学及相关指标均有显著的改善效果,不良事件的发生率较低且预后状况良好,值得临床参考借鉴。

被动式木窗双端铣削加工定位夹紧装置的设计与研究

为满足欧式木窗定制化尺寸变化的需求,设计一种尺寸自适应定位夹紧装置,应用有限元软件对木窗夹紧过程进行静力学分析,在满足木窗夹紧的要求下,使木窗弹性变形在合理范围。同时为了满足轻量化设计要求对压辊连接架进行拓扑优化设计,根据拓扑优化结果改进压辊连接架结构,对优化后的模型进行静力学分析验证,最终得到优化后的工件。结果表明,优化后压辊连接架重量明显下降,满足相关使用要求。

考虑连杆和关节柔性的工业机器人大臂静动态性能优化

为提高工业机器人整体性能,减小其静动态性能误差,提出一种综合考虑工业机器人连杆和关节柔性的拓扑优化方法。将机器人动力学与拓扑优化相结合,以变密度法(Solid isotropic material with penalization,SIMP)为基础,通过线性加权和法建立工业机器人大臂的多目标拓扑优化函数模型,基于柔性多体动力学理论,利用有限元软件和多体动力学软件建立含关节、连杆柔性的机器人刚柔耦合动力学仿真模型,获得机器人在极限工况下大臂载荷谱,最后,利用层次分析法确定优化目标函数中各子目标的权重系数,并对函数进行求解。优化结果显示,优化后机器人大臂刚度和固有频率都得到提高,并且质量下降18.71%。通过虚拟样机技术重构机器人模型,并对其整体进行分析,结果表明,最大负载作用下,机器人最大变形量从0.208 mm降至0.188 mm,静态变形量误差减小9.62%;动态定位误差从0.777 mm降至0.687 mm,定位精度提高11.58%。上述拓扑优化方法为提升工业机器人整体静动态性能提供了有效的理论参考。

座椅静态舒适性仿真与性能优化

为提高普通家用轿车的座椅静态舒适性,基于SAE-J826工装有限元模型和CASIMIR软件提供的第50百分位柔性人体有限元模型,提出了包含H点位置预测和座垫压力分布均匀性的座椅静态舒适性仿真分析方法,并利用HyperStudy优化工具平衡和提升了座椅静态舒适性能,仿真结果与试验结果取得了较好的一致性。

局部区域GNSS地壳形变监测系统设计与精度分析

为探索页岩气开采与地壳形变的关系、地表形变对页岩气压裂的响应等,布设一套GNSS跨断层形变监测系统。该系统综合使用静态和动态测量方法采集地表形变信息,结合多种GNSS定位方式增加监测区域地表动态位移信号探测的可靠性,并利用网络通讯与云服务器实现数据的自动化传输、设备的远程管理和站点的动态监测。考虑到测量误差与形变量之间的可区分度问题,文章从测量精度方面进行详细的分析。静态测量计算结果表明,单日基线解和PPP静态解精度在水平和垂直方向均可达到10 mm以内。四川泸定6.8级地震动态定位计算结果表明,RTK解、PPK解和PPP动态解时间序列中,瞬态地表位移信号的可识别程度也可达到10 mm以内。精度分析结果认为该系统可以较好地反映监测区域的部分长期和瞬态形变信息。

一种简单的低成本航姿系统标定及修正方法

在对低成本航姿系统进行加速度计与磁力计的标定中,通常磁力计的信噪比更低,仅使用椭球拟合法标定传感器误差参数结果是不够精确的;为了提高标定结果的准确性,提出了一种在多位置条件下基于椭球拟合约束和点积法的误差参数标定及修正方法;首先,在静态多位置下获取15对低噪声的测量数据并进行椭球拟合标定,其次,用补偿后的磁力计数据分布特征构建椭球约束条件,通过点积法计算地磁矢量与水平面夹角,并以其均方差来量化修正效果,对磁力计中可观性差的轴间不正交误差参数和传感器间非对准误差参数进行修正,最终提升标定效果;仿真和实测的试验结果表明,在同等椭球拟合约束下,该方法相比于独立使用椭球拟合法和点积不变法,地磁矢量与水平面夹角的均方差下降了25%以上,且具有简单易用的特点。

拉钩筋自动弯折装置设计与分析

针对当前拉钩筋装配化施工安装工艺需求,设计一种拉钩筋弯折装置。基于拉钩筋弯折工艺试验,提出了具有夹紧和弯折功能的装置构型。基于弯折装置结构特点,通过理论分析的方法建立了夹紧和弯折机构的运动学模型。基于弯折机构使用和设计要求,采用虚拟样机技术对弯折机构进行多体动力学和有限元结构静力学仿真分析。结果表明:弯折机构在运动过程中动作平滑,各杆件结构强度和刚度在合理范围之内,满足机构运动的平顺性和机械结构的可靠性要求。设计了弯折驱动液压缸电液位置控制系统,通过仿真验证了控制系统的可行性。最后,通过试验对弯折装置使用性能进行验证,结果表明:拉钩筋弯折装置整体结构性能满足设计和工程要求,极大提升了拉钩筋安装效率,达到预期目标。

基于GNSS的五塔连续斜拉桥主梁上CPⅢ平面网快速测量方法试验研究及应用

大跨度桥梁的长大连续梁会随着温度的变化,产生较大的纵向和竖向位移,导致连续梁桥上CPⅢ点坐标存在多值性,设站精度无法满足高铁对轨道板测量相关精度要求。本文提出了一种基于GNSS静态测量的连续梁上CPⅢ点平面坐标快速测量新方法,并依托郑济高铁长清黄河特大桥,设计了实际测量试验,并对新方法的可行性进行了验证。试验结果表明,这种基于GNSS的CPⅢ点平面坐标快速测量方法,在观测时长为30 min的情况下就能达到大跨度桥梁上底座板、轨道板等施工对CPⅢ平面网相关测量精度的要求。

基于静态磁源通过特性的磁定位导航气管插管装置的研制

目的基于静态磁源的通过特性,设计磁定位导航气管插管装置,以提高声门暴露困难情况下的气管插管成功率。方法本磁定位导航气管插管装置由柔性磁定位脖套、主控制器、磁引导条、导航磁体组成。通过硬件设计和软件编程,本装置主控单元以STM32F103C6T6微控制器为核心,利用磁定位脖套采集的磁感应强度数据,采用基于静态磁源通过特性的磁定位算法对柔性磁引导管条尖端进行定位。本装置通过可编程光源和蜂鸣器实现报警功能,借助导航磁体诱导磁引导条尖端响应磁体以实现磁导航。结果在磁定位导航系统的辅助下,相较于无磁定位导航系统辅助,非麻醉专业背景的医学生在模拟声门暴露困难条件下进行气管插管的一次成功率明显提高,差异有统计学意义(P<0.05),且平均插管用时保持在气管插管安全时限内,差异有统计学意义(P<0.05)。结论本研究设计的磁定位导航气管插管装置操作简便,在声门暴露困难条件下的气管插管中优势明显,可有效提高困难气道气管插管的一次成功率,减少并发症的发生,提高医疗质量安全,促进我国生命急救体系高水平发展。

星源照射多基地雷达系统目标定位建模及精度分析

星源照射多基地雷达系统由一个星载发射源与多个接收站组成,这种一发多收的雷达系统定位精度较单星定位精度高。因为工作体制和构型原因,一发多收雷达系统的定位精度受多种因素影响。为理清多基地雷达系统定位精度的影响因素,文中给出一种典型的一发多收雷达系统定位模型;其次,从几何稀释因子(GDOP)角度出发,对比不同接收站数量对定位精度的影响,发现雷达系统接收站数量为三收或四收时系统效费比较高;然后,研究了不同探测构型所对应的一发三收雷达系统定位精度,发现顶角为120°的Y形布局方式下系统定位精度最优;最后,给出了系统定位精度随目标高度的变化。

PWM频率对超精密机床主轴动态性能影响研究

为了分析多轴联动超精密机床伺服驱动器的PWM频率对超精密机床动态性能的影响,研究基于一款国产超精密机床的气体静压主轴,对其控制系统进行Simulink建模、仿真,并开展位置控制实验。通过主轴电机的动态特性方程对PWM型驱动器控制下的超精密机床主轴动态响应进行建模,模拟不同PWM频率下的主轴电机的电流、转矩和转速的响应波形,分析仿真数据,得到被控对象和PWM频率之间的控制律。在此基础上,以主轴的重复定位精度作为动态性能参数,搭建超精密机床主轴动态性能测试平台,通过对重复定位精度实验数据与仿真结果进行线性相关度分析,定量评价其相关度。最终得到气体静压主轴在PWM频率为20~60 kHz的范围内动态性能显著增强,而在60~100 kHz频率范围内的增强的趋势变缓,主轴动态性能的最优PWM频率参数为60 kHz。在设计选型阶段为超精密机床控制系统的参数选择提供了参考。

六系统融合静态和动态精密单点定位性能评估

本文基于全球均匀分布的100个测站分析了GPS、GLONASS、Galileo、BDS-2、BDS-3和QZSS六系统融合静态和动态PPP定位性能。结果表明:多系统融合极大地减少了收敛时间,提高了定位精度。单GPS和六系统融合静态PPP水平、高程和三维分量平均收敛时间分别为18.5、18.0、19.0 min和11.5、12.0、12.5 min,1 h定位精度分别为1.9、2.2、2.1 cm和1.2、1.5、1.4 cm。单GPS和六系统融合动态PPP水平、高程和三维分量平均收敛时间分别为34.5、33.5、36.0 min和15.0、15.5、16.5 min,收敛后定位精度分别为1.9、2.6、2.3 cm和0.9、1.6、1.3 cm。

The Topology Optimization of Oil Cylinder Mounting

The method of the structural topology optimization is often used to design machine in the early stage of the mechanical design.And the mechanical structures use the topology design to produce a new still and lightweight part with the different loading.A new structure is created through overlapping these new optimized structure.

An Underwater Robot Inspection Anomaly Localization Feedback System Based on Sonar Technology

This article introduces an underwater robot inspection anomaly localization feedback system comprising a real-time water surface tracking,detection,and positioning system located on the water surface,while the underwater robot inspection anomaly feedback system is housed within the underwater robot.The system facilitates the issuance of corresponding mechanical responses based on the water surface’s real-time tracking,detection,and positioning,enabling recognition and feedback of anomaly information.Through sonar technology,the underwater robot inspection anomaly feedback system monitors the underwater robot in real-time,triggering responsive actions upon encountering anomalies.The real-time tracking,detection,and positioning system from the water surface identifies abnormal conditions of underwater robots based on changes in sonar images,subsequently notifying personnel for necessary intervention.