Geometric Error Identification of Gantry-Type CNC Machine Tool Based on Multi-Station Synchronization Laser Tracers

Laser tracers are a three-dimensional coordinate measurement system that are widely used in industrial measurement.We propose a geometric error identification method based on multi-station synchronization laser tracers to enable the rapid and high-precision measurement of geometric errors for gantry-type computer numerical control(CNC)machine tools.This method also improves on the existing measurement efficiency issues in the single-base station measurement method and multi-base station time-sharing measurement method.We consider a three-axis gantry-type CNC machine tool,and the geometric error mathematical model is derived and established based on the combination of screw theory and a topological analysis of the machine kinematic chain.The four-station laser tracers position and measurement points are realized based on the multi-point positioning principle.A self-calibration algorithm is proposed for the coordinate calibration process of a laser tracer using the Levenberg-Marquardt nonlinear least squares method,and the geometric error is solved using Taylor’s first-order linearization iteration.The experimental results show that the geometric error calculated based on this modeling method is comparable to the results from the Etalon laser tracer.For a volume of 800 mm×1000 mm×350 mm,the maximum differences of the linear,angular,and spatial position errors were 2.0μm,2.7μrad,and 12.0μm,respectively,which verifies the accuracy of the proposed algorithm.This research proposes a modeling method for the precise measurement of errors in machine tools,and the applied nature of this study also makes it relevant both to researchers and those in the industrial sector.

Enhanced measurement precision with continuous interrogation during dynamical decoupling

Dynamical decoupling(DD)is normally ineffective when applied to DC measurement.In its straightforward implementation,DD nulls out DC signal as well while suppressing noise.This work proposes a phase relay method that is capable of continuously interrogating the DC signal over many DD cycles.We illustrate its efficacy when applied to the measurement of a weak DC magnetic field with an atomic spinor Bose-Einstein condensate.Sensitivities approaching standard quantum limit or Heisenberg limit are potentially realizable for a coherent spin state or a squeezed spin state of 10000 atoms,respectively,while ambient laboratory level noise is suppressed by DD.Our work offers a practical approach to mitigate the limitations of DD to DC measurement and would find other applications for resorting coherence in quantum sensing and quantum information processing research.

Development of diabetic complications and influencing factors among 32653 type 2 diabetes patients:retrospective cohort study using a multi-state Markov

Background:Patients with type 2 diabetes are at high risk for developing multiple chronic complications.However,there is a lack of studies of the cumulative number of diabetic complications in China.Methods:A retrospective cohort study was performed from 2009 to 2021.Type 2 diabetes patients who were first diagnosed after the age of 35 years between January 1,2009,and December 31,2017,were included.Five states were defined according to the number of chronic complications:no(S0),one(S1),two(S2),three(S3),and four or more complications(S4).A multi-state Markov model was constructed to estimate transition probability,transition intensity,mean sojourn time,and the possible factors for each state.Results:The study included 32653 type 2 diabetes patients(mean age,59.59 years;15929(48.8%)male),and mean follow-up time of 7.75 years.In all,4375 transitions were observed.The 12-year transition probability of from state S0 to S1 was the lowest at 16.4%,while that from S2 to S3 was the highest,at 45.6%.Higher fasting blood glucose,lower high-density lipoprotein cholesterol,higher total cholesterol,and an unhealthy diet were associated with higher risk of progression from S0 to S1.Being female,less than 60 years old,weekly physical activity,and vegetarian diet decreased this risk.Being female and less than 60 years old reduced the likelihood of transition from S1 to S2,whereas lower high-density lipoprotein cholesterol increased this likelihood.Conclusions:Following the occurrence of two complications in type 2 diabetes patients,the risk for accumulating a third complication within a short time is significantly increased.It is important to take advantage of the stable window period when patients have fewer than two complications,strengthen the monitoring of blood glucose and blood lipids,and encourage patients to maintain good living habits to prevent further deterioration.

Interrogating a Fiber Bragg Grating Vibration Sensor by Narrow Line Width Light

A method to interrogate fiber Bragg grating vibration sensor by narrow line width light is demonstrated. The interrogation scheme takes advantage of the intensity modulation of narrow spectral bandwidth light, such as distributed feedback laser, when a reflection or transmission spectrum curve of an fiber Bragg grating （FBG） moves due to the strain which is applied on the sensor. The sensor＇s response to accelerating frequency and amplitude is measured by experiment. The factors which have impacts on the sensitivity of the interrogation system are also discussed.

Stroke optimization of a novel multi-station rotary polishing robot based on workspace analysis

In order to meet the polishing requirement of faucets and other products,a novel multi-station rotary polishing robot is designed,which is a PPPR + RR type of degree of freedom( DOF) distribution structure,and is similar to dual-arm robot. Forward and inverse kinematic analysis is carried out by robot modeling. In order to make this robot structure more compact,first of all,X,Y and Z three moving degrees of freedom( DOF) limit stroke polishing need is calculated by using an artificial fish swarm algorithm,which analyzes dexterous workspace of this robot. Then,on the basis of the above analysis,the three DOF stroke is optimized. Simulation and polishing experimental results verify that this polishing robot with optimized stroke parameters can meet the polishing needs of faucets and other bathroom pieces.

Quality Stability of Multi-Station Assembly Process Based on Variation Stream

To analyze the physical structure of assembly process and assure product quality, the quality stability of multi-station assembly process was investigated. First, the assembly process was modeled as a one-dimensional discrete variant system by state space equation based on variation stream. Then, the criterion to judge whether the process is stable or not and the index, stability degree, to show the level of stability were proposed by analyzing the bounded-input bounded-output (BIBO) stability of system. Finally, a simulated example of a sheet metal assembly process with three stations, was provided to verify the effectiveness of the proposed method.

Study on quality evaluation model in multi-station assembly processes

Based on features of dimension variation propagation in multi-station assembly processes,a new quality evaluation model of assembly processes is established. Firstly,the error source of multi-station assembly system is analyzed,the relationship of dimension variation propagation in multi-station assembly processes is studied and the state equation for variation propagation is constructed too. Then,the feature parameters which influence variation propagation and accumulation in multi-station assembly processes are found to evaluate quality characteristic of the assembly system. Through the derivation of equation on dimension variation propagation,station coefficient matrices which are combined and conversed to determine the max eigenvalue are educed. The max eigenvalue is multiplied by the weight coefficient to establish the quality evaluation model in multi-station assembly processes. Furthermore,assembly variation indexes are proposed to judge of the assembly technology process. Finally,through the practical example,the application of the model and assembly variation indexes are presented.

Synthesized Multi-station Tribo-test System for Bio-tribological Evaluation in Vitro

Tribological tests play an important role on the evaluation of long-term bio-tribological performances of prosthetic materials for commercial fabrication.Those tests focus on the motion simulation of a real joint in vitro with only normal loads and constant velocities,which are far from the real friction behavior of human joints characterized with variable loads and multiple directions.In order to accurately obtain the bio-tribological performances of artificial joint materials,a tribological tester with a miniature four-station tribological system is proposed with four distinctive features.Firstly,comparability and repeatability of a test are ensured by four equal stations of the tester.Secondly,cross-linked scratch between tribo-pairs of human joints can be simulated by using a gear-rack meshing mechanism to produce composite motions.With this mechanism,the friction tracks can be designed by varying reciprocating and rotating speeds.Thirdly,variable loading system is realized by using a ball-screw mechanism driven by a stepper motor,by which loads under different gaits during walking are simulated.Fourthly,dynamic friction force and normal load can be measured simultaneously.The verifications of the performances of the developed tester show that the variable frictional tracks can produce different wear debris compared with one-directional tracks,and the accuracy of loading and friction force is within ？5%.Thus the high consistency among different stations can be obtained.Practically,the proposed tester system could provide more comprehensive and accurate bio-tribological evaluations for prosthetic materials.

Controllers Design for the Multi-Shuttle and Multi-Station Transportation System

Nowadays, the Multi-Shuttle and Multi-Station Transportation System (MMTS) is one of the most interesting research topics in many fields of industries. It is an effective solution to reduce unexpected accidents that occur during transportation as well as increase productivity in manufacturing. The aim of this paper is to introduce the controller design for the MMTS which is built in our BK-Recme BioMech Lab at Ho Chi Minh City University of Technology (VNU-HCM), Viet Nam. Based on the design of this system, the control algorithms will be conducted to check the operation of the whole system. To evaluate the feasibility and effectiveness of this model, we design a series of random instances for different quantities of nodes as well as the different quantities of shuttles. Our system includes 4 stations and 6 shuttles which are assembled in the serial chain system. However, the number of stations and number of shuttles can be expanded to any desired ones which are based on the requirement of the industries. In this paper, we mainly focus on the controller design of this system to make it operate in an effective way that the goods will be transported and delivered to the target station as fast as possible. In order to solve the large-scale instances and realistic transport problems, we propose three algorithms for three progresses as shuttles calling, path reading and shuttles communicating. The shuttles calling is to decide which shuttle should be called to the start-node. Path reading to determine the shortest way to go from start-node to end-node. Finally, shuttles communicating, which allow one shuttle to interact with the next shuttles so we have a loop of orders (shuttle 1 to shuttle 2;shuttle 2 to shuttle 3;etc.;shuttle n-1 to shuttle n). This proposes solution can help us to solve the huge numbers of shuttles and stations in the system. The specific result of this study is applying Dijkstra’s algorithm to propose an algorithm that allows handling a transportation system without caring about the number of shuttles as well as the number of stations for the closed-loop path. Several test problems are carried out in order to check the feasibility and the effectiveness of our purposed control algorithm.

A Two-Step Algorithm to Estimate Variable Importance for Multi-State Data:An Application to COVID-19

Survival data with amulti-state structure are frequently observed in follow-up studies.An analytic approach based on a multi-state model(MSM)should be used in longitudinal health studies in which a patient experiences a sequence of clinical progression events.One main objective in the MSM framework is variable selection,where attempts are made to identify the risk factors associated with the transition hazard rates or probabilities of disease progression.The usual variable selection methods,including stepwise and penalized methods,do not provide information about the importance of variables.In this context,we present a two-step algorithm to evaluate the importance of variables formulti-state data.Three differentmachine learning approaches(randomforest,gradient boosting,and neural network)as themost widely usedmethods are considered to estimate the variable importance in order to identify the factors affecting disease progression and rank these factors according to their importance.The performance of our proposed methods is validated by simulation and applied to the COVID-19 data set.The results revealed that the proposed two-stage method has promising performance for estimating variable importance.

藏缅语疑问语气助词的类型学特征——兼与汉语比较

本文运用语言类型学和描写语言学的理论和方法,在考察、比较50多种藏缅语族语言及方言疑问语气助词的基础上,指出藏缅语有疑问语气助词发达型、次发达型和不发达型三种类型;部分疑问语气助词存在多功能性,即除了表示疑问语气外,还能表达人称、数、方向等意义;不同语言间的疑问语气助词同源词较少、只有部分存在同源关系,而且分布不平衡。藏缅语与汉语是有同源关系的亲属语言,二者有相同点,也有差异。通过比较发现,藏缅语、汉语分析性语言类型的共性决定了疑问语气助词的基本特点相似,但分析性强弱不同又导致了疑问语气助词的丰富程度存在差异。汉语虽在上古阶段就出现了疑问语气助词,但应当是在与藏缅语分化后产生的。

运用5G通信技术远程程控心脏置入型电子设备的有效性及安全性评价

目的:探讨与技术服务人员术中现场程控、测试心脏置入型电子设备(cardiac implantable electrical devices,CIEDs)各项参数的常规方式相比,该非接触式远程程控系统在CIEDs置入过程中的的安全性和有效性。方法:本研究为回顾性研究。依照时间顺序,连续分析了自2020年8月至2021年3月,于我院接受CIEDs置入的110例患者,根据术中程控及测试方式,分为常规程控组及非接触组。入选患者中,59例常规组患者由技术服务人员术中现场程控,其余51例非接触组患者通过新型远程非接触系统程控。结果:常规组的开关门频率高于非接触组[(9.8±1.8)vs.(5.8±1.2),P<0.05]。在CIEDs置入期间和术后12个月时,常规组和非接触组之间的设备相关参数差异及手术相关不良事件差异无统计学意义。结论:基于5G通信传输技术的新型非接触性程控系统与传统的程控方法相比,是安全有效的。

河北孟村方言疑问代词的非疑问用法

与普通话的疑问代词非疑问用法相比,孟村方言的疑问代词非疑问用法有自己的特色。表全指时,孟村方言采用三种方式:直接用疑问代词、疑问代词重叠和加不定性标记“任”。它们与表示无条件意义的连词(称为前项关联词)、副词“都”和“也”(称为后项关联词)共现情况不一样:第一种表达方式能构成A、B、C三种句式,第二、三种方式能构成C、D两种句式。第二、三种方式限于“谁”“哪”“嘛(儿)”三个单音节疑问代词,组合能力受限。表借指时,孟村方言“总=么”出现在列举项之前,总括所有的同类项。表虚指和独用的“总=么着”“总=着”有一些用法是普通话所没有的,“总=么着”表示用于指称当前的某种情状,强调该情状符合自己的预期。

从话轮转换看侦查讯问话语权的控制

侦查讯问人员可以通过恰当的话轮转换策略实现对嫌疑人的控制与引导,从而获取嫌疑人的供述和辩解。获取话轮常用打断、重述、应答性言语反馈信号、“那……”以及直接回应等手段。维持话轮常用表提醒义的叹词“啊”、提高音量与语速、表示关联关系的词语、套话(如“否则的话”)和非真实疑问句(如“知道吧?”)。让渡话轮以问话为主,包括仅仅为了互动的问话和获取信息的问话。获取基本信息多用特指问句,获取认知信息引导嫌疑人供述多用正反问和是非问,获取案件信息多用特指问句,同时配合其他手段限制嫌疑人的回答,如在问话前面或后面增加限制性话语以缩小嫌疑人的答话空间。

庭审实质化视角下讯问被告人程序改革研究

“以审判为中心”的刑事诉讼制度改革,重心在于庭审实质化的实现。然而,我国刑事法庭调查阶段讯问被告人程序存在诸多问题,成为了庭审实质化的明显阻碍。该程序在我国刑事诉讼中发挥着对庭审走向定调、确定被告人认罪态度及案件争点和与控方优势暗合的实际作用。比较研究表明,刑事诉讼程序包括讯问被告人程序的设计应始终遵循“不得强迫任何人证明自己有罪”的基本理念。我国的讯问被告人程序,是“职权主义诉讼模式”“印证证明模式”和“案卷笔录中心主义”共同形塑下的产物。在未来的《刑事诉讼法》修改中,应当对该程序进行改革,赋予被告人选择是否作为控方证人接受检察官询问的权利,凸显被告人的主体性地位,优化调整庭审布局,以推进庭审实质化的落实,进而确保司法公正的实现。

基于D-D中子源的乏燃料组件钚含量测量装置设计

为了满足国际社会上对于乏燃料组件内特种可裂变材料钚的保障监督需求,以持续提供核材料信息,研究乏燃料组件内钚含量测量的非破坏性分析技术显得尤为重要。本文采用主动法,以压水堆乏燃料组件作为测量对象,D-D中子作为质询中子源,开展了乏燃料组件钚含量测量装置的设计研究。采用MCNPX软件,基于最大化探测器计数率和使各探测器计数率尽量一致的目的,对测量装置中的中子管与探测器组件距离、中子管慢化材料及其厚度、探测器组件与中子管高度差、探测器组件中慢化体厚度等关键参数进行了模拟计算。此研究为中子质询乏燃料组件钚含量测量技术研究及实验验证打下了基础。

基于Ramsey干涉的小型化冷原子微波钟研究进展

基于Ramsey干涉的冷原子钟已被证实具有很高的稳定度和准确度。经过近30年的发展,冷原子钟技术水平不断提高,运行可靠性不断提升,并逐步在便携式和可移动时频系统上得到应用,冷原子钟的小型化已成为该领域的研究热点。阐述了基于Ramsey干涉的冷原子微波钟的工作原理及运行过程,分析了冷原子钟小型化的关键技术,梳理了目前小型化冷原子钟的研究进展,表明了基于腔内冷原子制备的原位干涉技术是实现冷原子钟小型化的有效途径,由此发展的冷原子钟兼具高性能、高可靠、高集成化等优势。

合理化讯问策略的应用风险及使用限度

随着刑事诉讼制度改革对侦查讯问工作提出更高要求,传统的对抗式讯问模式已经难以适应新形势的发展。合理化策略作为一种软审讯方法,结合心理学理论和法律实践,能够化解讯问双方的对立情绪,增强犯罪嫌疑人的合作意愿,保障其供述自愿性,最终实现讯问目的。研究合理化策略的应用技巧以及具体操作方法,探讨合理化讯问策略在实践应用中的风险与使用限度,有助于进一步加强对合理化讯问策略的理解,从而推进侦查讯问工作的规范化和科学化。

多模态智能审讯技术的原理与实战化应用路径研究

多模态智能审讯技术通过非接触式生理检测、面部表情与肢体动作分析、眼动检测等多源异构数据融合算法,实现审讯中对犯罪嫌疑人心理的智能化分析和评估以及谎言甄别。将犯罪嫌疑人心理分析和评估意见输入审讯专家系统与知识库中大量的专家知识和经验进行碰撞输出审讯策略建议,为侦查人员提供专家服务。研发多模态智能审讯技术需要在审讯室采集真实的数据,构建一个数据量较大的、可靠的数据库,并充分挖掘和利用不同模态数据,构建多模态智能审讯技术与审讯专家系统同步化的人机结合的审讯技术,为审讯助力。多模态智能审讯技术作为审讯技术的典型代表,改变了传统的以人力资源为主的经验模式,无疑给审讯带来了崭新的活力和深刻的变革。

一种机载询问机波束指向偏差修正算法

针对在一次雷达方位牵引条件下使用的机载敌我识别询问机,载机转弯段存在波束指向偏差大的问题,深入分析了误差来源并对误差影响程度进行了仿真分析,指出载机转弯时,若按照雷达的指示方位设置敌我识别询问机波束指向,波束不能够对准目标。提出了一种机载询问机的波束指向偏差修正算法,修正了敌我识别询问机波束指向并进行了仿真验证。仿真结果表明:所提出的修正算法能够使敌我识别询问机在载机转弯段维持高指向精度,促进了机载敌我识别/二次雷达系统的发展。