A Mixed Real-time Algorithm for the Forward Kinematics of Stewart Parallel Manipulator

Aimed at the real-time forward kinematics solving problem of Stewart parallel manipulator in the control course, a mixed algorithm combining immune evolutionary algorithm and numerical iterative scheme is proposed. Firstly taking advantage of simpleness of inverse kinematics, the forward kinematics is transformed to an optimal problem. Immune evolutionary algorithm is employed to find approximate solution of this optimal problem in manipulator＇s workspace. Then using above solution as iterative initialization, a speedy numerical iterative scheme is proposed to get more precise solution. In the manipulator running course, the iteration initialization can be selected as the last period position and orientation. Because the initialization is closed to correct solution, solving precision is high and speed is rapid enough to satisfy real-time requirement. This mixed forward kinematics algorithm is applied to real Stewart parallel manipulator in the real-time control course. The examination result shows that the algorithm is very efficient and practical.

Model-based framework for multi-axial real-time hybrid simulation testing

Real-time hybrid simulation is an efficient and cost-effective dynamic testing technique for performance evaluation of structural systems subjected to earthquake loading with rate-dependent behavior. A loading assembly with multiple actuators is required to impose realistic boundary conditions on physical specimens. However, such a testing system is expected to exhibit significant dynamic coupling of the actuators and suffer from time lags that are associated with the dynamics of the servo-hydraulic system, as well as control-structure interaction （CSI）. One approach to reducing experimental errors considers a multi-input, multi-output （MIMO） controller design, yielding accurate reference tracking and noise rejection. In this paper, a framework for multi-axial real-time hybrid simulation （maRTHS） testing is presented. The methodology employs a real-time feedback-feedforward controller for multiple actuators commanded in Cartesian coordinates. Kinematic transformations between actuator space and Cartesian space are derived for all six-degrees-of- freedom of the moving platform. Then, a frequency domain identification technique is used to develop an accurate MIMO transfer function of the system. Further, a Cartesian-domain model-based feedforward-feedback controller is implemented for time lag compensation and to increase the robustness of the reference tracking for given model uncertainty. The framework is implemented using the 1/5th-scale Load and Boundary Condition Box （LBCB） located at the University of Illinois at Urbana- Champaign. To demonstrate the efficacy of the proposed methodology, a single-story frame subjected to earthquake loading is tested. One of the columns in the fraane is represented physically in the laboratory as a cantilevered steel column. For real- time execution, the numerical substructure, kinematic transformations, and controllers are implemented on a digital signal processor. Results show excellent performance of the maRTHS framework when six-degrees-of-freedom are controUed at the interface between substructures.

Comparative study on efficacy of three sperm-separation techniques

Aim: To evaluate the comparative effectiveness of real-time sperm separation technique (Wang's tube method) andother two conventional methods in isolating high-quality sperm preparation, and to compare the spouse pregnancy ratein intrauterine insemination (IUI) with sperm preparations isolated by these methods. Methods: The effectivenessof the real-time sperm separation technique, the conventional swim-up and the Percoll discontinuous density gradientmethods in isolating sperm preparations from 60 infertile patients (20 with apparently normal semen and 40, abnormalsemen contaminated with microorganisms and other impurities) was evaluated and compared. The microorganisms to beremoved included bacteria, vires, Chlamydia trachomaticum, Ureaplsama urealyticum, etc. The spouse pregnancyrates in IUI with sperm preparations isolated by these three techniques from 80 oligoasthenoteratospermic patients werealso compared. Results: The quality (including the percentages of normal form, normal-chromatin and motilesperm, and the grade of motility) of sperm obtained by the real-time sperm separation technique was much higher ( P< 0.01) as compared with those by the other two methods. The Wang's tube method was also more effective in remov-ing microorganisms and other impurities. The method provided a higher IUI pregnancy rate than the other two spermseparation techniques ( P < 0.05). Conclusion: The real-time sperm separation technique is the most effectivemethod so far available in isolating high-quality sperm samples to be used in assisted reproduction.

Development of a Microcomputer System for 3D Kinematic Simulation

Software system is developed for real-time processing of 3D graphics by Visual C + + calling functions in PpenGL under the environment of Windows NT(Windows 95). By 3D modeling after mathematics modeling automatic generation of 3D soid and real-time processing of 3D animaation are realized, and a microcomputer system is developed for real-time kinematic simulation.

A Fast Approach for Time Optimal and Smooth Trajectory Planning of Robot Manipulators

In this paper, a fast approach to generate time optimal and smooth trajectory has been developed and tested. Minimum time is critical for the productivity in industrial applications. Meanwhile, smooth trajectories based on cubic splines are desirable for their ability to limit vibrations and ensure the continuity of position, velocity and acceleration during the robot movement. The main feature of the approach is a satisfactory solution that can be obtained by a local modification process among each intermal between two consecutive via-points. An analytical formulation simplifies the approach to smooth trajectory and few,iterations are enough to determine the correct values. The approach can be applied in many robot manipulators which require high performance on time and smooth. The simulation and application of the approach on a palletizer robot are performed, and the experimental results provide evidence that the approach can realize the robot manipulators more efficiency and high smooth performance.

EtherCAT实时性对SCARA机器人轨迹精度的影响研究

以双相机引导机械手贴合系统为研究背景,研究了EtherCAT实时性对SCARA机器人运动轨迹精度的影响。对SCARA机器人的运动学进行建模,采用标准的D-H建模法,确定机器人的连杆参数,分析机器人的正运动学和逆运动学,并采用解析法求解运动学逆解。利用MATLAB中的机器人工具箱Robotics Toolbox,对机器人的运动学进行仿真分析,验证了运动学模型建立的正确性。分析了EtherCAT的实时性,通过EtherCAT的分布时钟同步机制,由抓包工具为以太网报文打上时间戳;采用wireshark抓包软件,分析数据传输过程中的抖动延时;采用示波器,测出同步误差,验证了EtherCAT的高同步性。采用七次多项式轨迹规划算法,在试验平台进行了轨迹精度的验证。验证结果表明:EtherCAT同步时,其速度给定与反馈的偏差小、波动小。EtherCAT实时性的研究为EtherCAT在机器人领域的应用提供了理论基础,为EtherCAT在数控加工领域的应用提供参考。

Multiplex qPCR for serodetection and serotyping of hepatitis viruses: A brief review

The present review describes the current status of multiplex quantitative real time polymerase chain reaction(q PCR) assays developed and used globally for detection and subtyping of hepatitis viruses in body fluids. Several studies have reported the use of multiplex q PCR for the detection of hepatitis viruses, including hepatitis A virus(HAV), hepatitis B virus(HBV), hepatitis C virus(HCV), hepatitis D virus(HDV), and hepatitis E virus(HEV). In addition, multiplex q PCR has also been developed for genotyping HBV, HCV, and HEV subtypes. Although a single step multiplex q PCR assay for all six hepatitis viruses, i.e., A to G viruses, is not yet reported, it may be available in the near future as the technologies continue to advance. All studies use a conserved region of the viral genome as the basis of amplification and hydrolysis probes as the preferred chemistries for improved detection. Based on a standard plot prepared using varying concentrations of template and the observed threshold cycle value, it is possible to determine the linear dynamic range and to calculate an exact copy number of virus in the specimen. Advantages of multiplex q PCR assay over singleplex or other molecular techniques in samples from patients with co-infection include fast results, low cost, and a single step investigation process.

Explicit Symplectic Geometric Algorithms for Quaternion Kinematical Differential Equation

Solving quaternion kinematical differential equations(QKDE) is one of the most significant problems in the automation, navigation, aerospace and aeronautics literatures. Most existing approaches for this problem neither preserve the norm of quaternions nor avoid errors accumulated in the sense of long term time. We present explicit symplectic geometric algorithms to deal with the quaternion kinematical differential equation by modelling its time-invariant and time-varying versions with Hamiltonian systems and adopting a three-step strategy. Firstly,a generalized Euler's formula and Cayley-Euler formula are proved and used to construct symplectic single-step transition operators via the centered implicit Euler scheme for autonomous Hamiltonian system. Secondly, the symplecticity, orthogonality and invertibility of the symplectic transition operators are proved rigorously. Finally, the explicit symplectic geometric algorithm for the time-varying quaternion kinematical differential equation, i.e., a non-autonomous and non-linear Hamiltonian system essentially, is designed with the theorems proved. Our novel algorithms have simple structures, linear time complexity and constant space complexity of computation. The correctness and efficiencies of the proposed algorithms are verified and validated via numerical simulations.

Dorsal root ganglion neurons promote proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells

Preliminary animal experiments have confirmed that sensory nerve fibers promote osteoblast differentiation, but motor nerve fibers have no promotion effect. Whether sensory neurons pro- mote the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells remains unclear. No results at the cellular level have been reported. In this study, dorsal root ganglion neurons （sensory neurons） from Sprague-Dawley fetal rats were co-cultured with bone marrow mesenchymal stem cells transfected with green fluorescent protein 3 weeks after osteo- genic differentiation in vitro, while osteoblasts derived from bone marrow mesenchymal stem cells served as the control group. The rat dorsal root ganglion neurons promoted the prolifera- tion of bone marrow mesenchymal stem cell-derived osteoblasts at B and 5 days of co-culture, as observed by fluorescence microscopy. The levels of mRNAs for osteogenic differentiation-re- lated factors （including alkaline phosphatase, osteocalcin, osteopontin and bone morphogenetic protein 2） in the co-culture group were higher than those in the control group, as detected by real-time quantitative PCR. Our findings indicate that dorsal root ganglion neurons promote the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells, which pro- vides a theoretical basis for in vitro experiments aimed at constructing tissue-engineered bone.

Object-Based Classification of Urban Distinct Sub-Elements Using High Spatial Resolution Orthoimages and DSM Layers

This paper aims to assess the ways in which multi-resolution object-based classification methods can be used to group urban environments made up of a mixture of buildings, sub-elements such as car parks, roads, shades and pavements and foliage such as grass and trees. This involves using both unmanned aerial vehicles (UAVs) which provide high-resolution mosaic Orthoimages and generate a Digital Surface Model (DSM). For the study area chosen for this paper, 400 Orthoimages with a spatial resolution of 7 cm each were used to build the Orthoimages and DSM, which were georeferenced using well distributed network of ground control points (GCPs) of 12 reference points (RMSE = 8 cm). As these were combined with onboard RTK-GNSS-enabled 2-frequency receivers, they were able to provide absolute block orientation which had a similar accuracy range if the data had been collected by traditional indirect sensor orientation. Traditional indirect sensor orientation involves the GNSS receiver in the UAV receiving a differential signal from the base station through a communication link. This allows for the precise position of the UAV to be established, as the RTK uses correction, allowing position, velocity, altitude and heading to tracked, as well as the measurement of raw sensor data. By assessing the results of the confusion matrices, it can be seen that the overall accuracy of the object-oriented classification was 84.37%. This has an overall Kappa of 0.74 and the data that had poor classification accuracy included shade, parking lots and concrete pavements. These had a producer accuracy (precision) of 81%, 74% and 74% respectively, while lakes and solar panels each scored 100% in comparison, meaning that they had good classification accuracy.

Applying Global Positioning System Real-Time Kinematic Technology to Collection and Analysis of Rowing Information

To obtain higher accuracy of information concerning boat motion, the use of global positioning system (GPS) real-time kinematic (RTK) technology was investigated. Through RTK technology, a measurement precision of the ±1 cm range can be achieved. The research equipment included a GPS receiver and a personal digital assistant as a data control and processing unit. Real-time GPS data was captured and processed to acquire various parameters, including the boat track, velocity curve, stroke rate, and stroke distance. Using this data, the quantitative information related to rowing training can be achieved. The results are helpful for analyzing the biomechanical parameters of rowing techniques and for evaluating training efficiency.

Real-time and dynamic transduction technique for simultaneous detection of O_2 and CO_2

OXYGEN and carbon dioxide are the coexistent gases closely related to life processes. In our pre-

Implementation of Dynamic Line Rating in a Sub-Transmission System for Wind Power Integration

Based on conventional static line rating method, the actual current carrying capability of overhead conductors cannot be judged. Due to continuous increment in electricity demand and the difficulties associated with new line constructions, the overhead lines are therefore required to be rated based on a method that should establish their real-time capability in terms of electricity transmission. The method used to determine the real-time ampacity of overhead conductors not only can enhance their transmission capacity but can also help in allowing excessive renewable generation in the electricity network. In this research work, the issues related to analyzing an impact of wind power on periodical loading of overhead line as well as finding its static and dynamic ampacities with line current are investigated in detail. Moreover, the investigation related to finding a suitable location for the construction of a 60 MW wind farm is taken on board. Thereafter, the wind park is integrated with a regional grid, owned by Fortum Distribution AB. In addition to that, the electricity generated from the wind park is also calculated in this project. Later on, the work is devoted to finding the static and dynamic line ratings for “VL3” overhead conductor by using IEEE-738-2006 standard. Furthermore, the project also deals with finding the line current and making its comparison with maximum capacity of overhead conductor (VL3) for loading it in such a way that no any violation of safe ground clearance requirements is observed at all. Besides, the line current, knowing the conductor temperature when it transmits the required electricity in the presence of wind power generation is also an important factor to be taken into consideration. Therefore, based on real-time ambient conditions with actual line loading and with the help of IEEE-738-2006 standard, the conductor temperature is also calculated in this project. At the end, an economic analysis is performed to evaluate the financial advantages related to applying the dynamic line ratings approach in place of traditional static line ratings technique across an overhead conductor (VL3) and to know how much beneficial it is to temporarily postpone the rebuilding and/or construction of a new transmission line. Furthermore, an economic analysis related to wind power system is taken into consideration as well to get familiar with the costs related to building and connecting a 60 MW wind farm with the regional grid.

基于相控阵合成孔径的颅骨轮廓快速测量算法研究

作为一项新兴的神经调控技术,经颅聚焦超声技术目前广泛应用于脑深部的神经调控与治疗中。颅骨的异形和声参数的极大差异性是导致聚焦超声穿透颅骨后实际焦点的偏移和焦域散焦的主要原因。本研究以合成孔径技术为基础,由相控阵发射超声信号并接收于颅骨内外轮廓反射的回波信号,同时计算得到颅骨轮廓点坐标,实现对颅骨轮廓的快速测量。建立仿真模型,并利用颅骨仿体对算法进行仿真与实验验证。仿真结果表明,颅骨模型外轮廓中心区域的最大探测误差为0.15 mm,边缘区域为0.4 mm;内轮廓中心区域最大探测误差为0.3 mm,边缘区域为0.5 mm。实验结果表明:颅骨仿体外轮廓中心区域的最大探测误差为0.4 mm,边缘区域为0.8 mm;内轮廓中心区域最大探测误差为0.6 mm,边缘区域为0.9 mm。所设计的颅骨轮廓快速测量算法能够实现在2 min内完成颅骨内外轮廓的精确测量,并控制最大测量误差在1 mm以内。与核磁共振扫描(MRI)以及电子计算机断层成像(CT)相比,降低了治疗成本和治疗时间,同时为下一步调整相控阵阵元发射延时,实现在颅内的实时精确聚焦,提供了新的方法和思路。

基于2.4 GHz无线技术的RTK定位系统

利用2.4 GHz无线技术,设计RTK(real time kinematic)定位系统.在两种实验场景下,进行对比实验,比较RTK定位系统和传统PVT(position velocity time)定位系统的定位误差.实验结果表明:两种实验场景下,相对于传统PVT定位系统,该文设计的RTK定位系统均有更小的定位误差.该文定位系统可应用于无人机、精准农业等领域.

一种智能手机GNSS精密定位随机模型构建方法及定位性能分析

全球导航卫星系统(GNSS)定位芯片已经成为智能手机中实现导航定位的重要传感器,随着信息化、智能化社会的不断发展和深入,人们对手机高精度定位服务的需求不断增加。在分析伪距残差与高度角、载噪比(C/N_(0))及手机GNSS原始观测信息的相关性时发现:相比于C/N_(0),手机GNSS原始观测信息中的ReceivedSvTimeUncertaintyNanos与伪距残差的相关性更高。因此,提出了一种基于岭回归和智能手机原始观测信息的GNSS精密定位随机模型构建方法。通过构建以手机原始观测信息为特征变量的岭回归模型,利用谷歌公开数据集训练该模型,学习伪距残差与各种特征变量之间的映射关系,进而在线预测伪距噪声,以此作为GNSS定位中观测值定权的依据。最后,进行实时动态定位(RTK)和精密单点定位(PPP)实验以验证新定权方法的定位性能,实验结果表明,相比传统C/N_(0)定权方法,新定权方法的定位精度在3组实验中平均提升幅度分别为24.9%,44.8%及39.3%。

Wide area real time kinematic decimetre positioning with multiple carrier GNSS signals

This paper presents the technical basis for wide area real time decimetre positioning services using multiple carrier signals transmitted by future GNSS such as modernized GPS and Compass systems. The first step is to form two ionosphere-reduced extra-widelanes (EWL) that have the minimal total noise levels in cycles, considering the effects of the ionospheric and tropospheric delays, orbital error, and phase noise terms in various observational environments. The proposed three carrier ambiguity resolution approach can determine the integer ambiguities of the selected EWL signals with geometry-free and geometry- based estimations respectively over the distances of typically hundreds of kilometres. With two ambiguity-fixed EWL signals, the kinematic positioning solutions can be achieved in decimetre level accuracy. A semi-simulation method is employed to generate three frequency Compass data to demonstrate the above expected performance for decimetre positioning services. Both theoretical and experimental results have demonstrated the overall 3D root mean square accuracy of better than 15 cm obtained through with a phase smoothing process over 120 epochs. The dominating error factor in this positioning result is the residual tropospheric biases, which would become less correlated as the baselines grow beyond hundreds of kilometres. With respect to dual-frequency based precise point positioning and wide area differential positioning solutions, a major advantage of using the third frequency signals is the convergence time being shorten from tens of minutes to a few minutes. In addition, due to the instant ambiguity resolution capability, phase breaks or cycle slips no longer affect the continuity of the solutions. This reliable decimetre positioning capability introduces a significant improvement to safety-of-life, liability-critical and professional applications.

复杂环境GNSS实时亚厘米级监测算法设计及性能分析

针对复杂监测场景下,由于卫星信号遮挡严重、多路径效应强、粗差和周跳频繁而造成观测数据质量差,严重影响全球卫星导航系统(GNSS)实时监测的精度、可靠性和可用性的问题,提出一种复杂环境下的GNSS实时亚厘米级监测算法:综合利用监测体的变化特征,从观测数据质量控制、滤波过程噪声自适应调节、GNSS解算短时中断后快速恢复等方面着手,设计一套适用于复杂环境的GNSS地质灾害实时高精度监测数据处理算法;并采用实测与仿真短基线数据评估算法性能。结果表明,在复杂观测场景下,提出的复杂环境GNSS监测算法能够实现实时亚厘米级定位精度,有效解决GNSS解算短时中断后的快速恢复问题,并能准确识别监测体的快速形变。

多模态超声心动图对肺动脉高压患者右心功能的诊断价值分析

目的探讨多模态超声心动图对肺动脉高压患者右心功能的诊断效能。方法选取2022年1月至2023年8月于金华市中心医院就诊的80例肺动脉高压患者纳入观察组,根据患者的肺动脉收缩压将其分为轻度组[40~50mmHg(1mmHg=0.133kPa),36例]、中度组(51~70mmHg,20例)和重度组(>70mmHg,24例);选取同期健康体检者80名纳入对照组,所有受试者均进行多模态超声心动图检测,对比其超声检查相关数据,评估多模态超声心动图对肺动脉高压患者右室收缩功能的诊断效能。结果观察组患者的右室舒张末期容积(right ventricular end diastolic volume,RVEDV)、右室收缩末期容积(right ventricular end systolic volume,RVESV)、右室整体无效做功(right ventricular global waste work,RVGWW)均显著高于对照组,右室每搏输出量(right ventricular stroke volume,RVSV)、右室射血分数(right ventrical ejection fraction,RVEF)、三尖瓣环收缩期位移(tricuspid annular plane systolic excusion,TAPSE)、整体纵向应变(global longitudinal strain,GLS)、右室整体做功效率(right ventricular global work efficiency,RVGWE)、右室整体做功指数(right ventricular global work index,RVGWI)、右室整体有效做功(right ventricular global constructive work,RVGCW)均显著低于对照组(P<0.05)。重度组患者的RVEDV、RVESV及RVGWW均显著高于中度组、轻度组,RVSV、RVEF、RVGWE、RVGWI、RVGCW均显著低于中度组、轻度组(P<0.05)。TAPSE、GLS、RVSV、RVEF、RVGWI五项联合诊断肺动脉高压患者右心功能的曲线下面积为0.911,敏感度为92.23%,特异性为96.45%。结论多模态超声心动图能有效评价肺动脉高压患者的右室收缩功能,值得临床推广应用。

基于Simulink对机械臂可视化上料研究

自动上料设备可以通过现代化技术实现数据采集和分析,以优化制造流程,提高生产效率和产品质量,从而更好地实现智能制造。为了实现链板等零件的自动上料过程,文章介绍了机械臂的三维可视化人机交互平台模型的构建过程,以Gluon机械臂为分析对象,进行正运动学分析和逆运动学验证,并通过Simulink搭建了控制系统模型,实现了对Gluon机械臂的联合仿真。仿真过程中,对各关节的旋转角度、角速度以及末端执行器的齐次变换矩阵实时显示。通过验证,为后期搭建实物平台提供了可行性支撑,为进一步优化和完善系统功能奠定了基础。