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| 1 | Type Synthesis of 4-DOF Parallel Kinematic Mechanisms Based on Grassmann Line Geometry and Atlas Method显示文摘Many methods are proposed to deal with the type synthesis of parallel kinematic mechanisms(PKMs),but most of them are less intuitive to some extent.Thus,to propose a concise and intuitive type synthesis method for engineering application is a very challenging issue,which should be further studied in the field.Grassmann line geometry,which can investigate the dimensions of spatial line-clusters in a concise way,is taken as the mathematic foundation.Atlas method is introduced to visually describe the degrees of freedom(DOFs)and constraints of a mechanism,and the dual rule is brought in to realize the mutual conversion of the freedom-space and constraint-space.Consequently,a systematic method based on Grassmann line geometry and Atlas method is generated and the entire type synthesis process is presented.Three type 4-DOF PKMs,i.e.,1T3R,2T2R and 3T1R(T:translational DOF;R:rotational DOF),are classified according to the different combinations of the translational DOFs and rotational DOFs.The type synthesis of4-DOF PKMs is carried out and the possible configurations are thoroughly investigated.Some new PKMs with useful functions are generated during this procedure.The type synthesis method based on Grassmann line geometry and Atlas method is intuitive and concise,and can reduce the complexity of the PKMs’type synthesis.Moreover,this method can provide theoretical guidance for other PKMs’type synthesis and engineering application.A novel type synthesis method is proposed,which solves the existing methods’problems in terms of complicated,not intuitive and unsuitable for practical application. | XIE Fugui LI Tiemin LIU Xinjun | 2013 | Chinese Journal of Mechanical Engineering2013，26，6： | 21 |
| 2 | Step kinematic calibration of a 3-DOF planar parallel kinematic machine tool显示文摘This paper presents a novel step kinematic calibration method for a 3 degree-of-freedom(DOF) planar parallel kinematic machine tool,based on the minimal linear combinations(MLCs) of error parameters.The method using mapping of linear combinations of parameters in error transfer multi-parameters coupling system changes the modeling,identification and error compensation of geometric parameters in the general kinematic calibration into those of linear combinations of parameters.By using the four theorems of the MLCs,the sets of the MLCs that are respectively related to the relative precision and absolute precision are determined.All simple and feasible measurement methods in practice are given,and identification analysis of the set of the MLCs for each measurement is carried out.According to the identification analysis results,a step calibration including step measurement,step identification and step error compensation is determined by taking into account both measurement costs and observability.The experiment shows that the proposed method has the following merits:(1) the parameter errors that cannot influence precision are completely avoided;(2) it reflects the mapping of linear combinations of parameters more accurately and enhances the precision of identification;and(3) the method is robust,efficient and effective,so that the errors in position and orientation are kept at the same order of the measurement noise.Due to these merits,the present method is attractive for the 3-DOF planar parallel kinematic machine tool and can be also applied to other parallel kinematic machine tools with weakly nonlinear kinematics. | CHANG Peng,WANG JinSong,LI TieMin,LIU XinJun & GUAN LiWen Department of Precision Instruments and Mechanology,Tsinghua University,Beijing 100084,China | 2008 | Science China(Technological Sciences)2008，51，12： | 9 |
| 3 | Kinematic Calibration and Forecast Error Compensation of a 2-DOF Planar Parallel Manipulator显示文摘Due to large workspace,heavy-duty and over-constrained mechanism,a small deformation is caused and the precision of the 2-DOF planar parallel manipulator is affected.The kinematic calibration cannot compensate the end-effector errors caused by the small deformation.This paper presents a method combined step kinematic calibration and linear forecast real-time error compensation in order to enhance the precision of a two degree-of-freedom(DOF) planar parallel manipulator of a hybrid machine tool.In the step kinematic calibration phase of the method,the end-effector errors caused by the errors of major constant geometrical parameters is compensated.The step kinematic calibration is based on the minimal linear combinations(MLCs) of the error parameters.All simple and feasible measurements in practice are given,and identification analysis of the set of the MLCs for each measurement is carried out.According to identification analysis results,both measurement costs and observability are considered,and a step calibration including step measurement,step identification and step error compensation is determined.The linear forecast real-time error compensation is used to compensate the end-effector errors caused by other parameters after the step kinematic calibration.Taking the advantages of the step kinematic calibration and the linear forecast real-time error compensation,a method for improving the precision of the 2-DOF planar parallel manipulator is developed.Experiment results show that the proposed method is robust and effective,so that the position errors are kept to the same order of the measurement noise.The presented method is attractive for the 2-DOF planar parallel manipulator and can be also applied to other parallel manipulators with fewer than six DOFs. | CHANG Peng LI Chengrong LI Tiemin | 2011 | Chinese Journal of Mechanical Engineering2011，24，6： | 5 |
| 4 | Experimental study on fire smoke movement in a multi-floor and multi-room building显示文摘Fire smoke movement of multi-floor and multi-room (MFMR) fire was studied at the model test building in State Key Laboratory of Fire Science (SKLFS). The ingredient, temperature, air pressure difference and air velocity of smoke were measured and analyzed. Meanwhile, the hazard of smoke ingredient to exposed occupants was analyzed based on the national standard, Occupational Exposure Limit for Hazardous Agents in the Workplace (GBZ2-2002). The experimental results showed that the maximum temperature difference in MFMR fire was located along the vertical height from the fire source. With the spreading and diffusion of smoke, the temperature of smoke layer would tend to be no difference. In the fire of woodpile and kerosene, the main smoke ingredients such as SO 2 , CO and CO 2 would first exceed human’s average physiological limit, while smoke ingredients such as NO and NO 2 would come behind. Because of the higher fluctuation range and frequency of air pressure difference of smoke in multi-layer building fire, the fire smoke would spread around everywhere of the passageway and made the human evacuation more difficult. | ZHONG Maohua 1, 2 , LI Peide 2 , LIU Tiemin 1 , WEI Xing 1, 2 & LIAO Guangxuan 2 1. National Center of Safety Science and Technology, State Administration of Work Safety, Beijing 100029, China 2. State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei 230026, China | 2005 | Science China(Technological Sciences)2005，48，3： | 4 |
| 5 | Short-term intermittent administration of CXCR4 antagonist AMD3100 facilitates myocardial repair in experimental myocardial infarction显示文摘stromal 的绑定导出房间的 factor-1 (SDF-1 ) 到半胱氨酸(C)-X-C 主题 chemokine 受体(CXCR4 ) 4 从骨头髓为茎和祖先房间 trafficking 作为一个关键信号出现了到发行量。我们的目的是在心肌的梗塞(MI ) 以后在愈合的过程期间调查 AMD3100 (一个特定的可逆 CXCR4 受体对手) 的每日的断断续续的管理的角色。Wistar 老鼠受到 MI, AMD3100 在外科以后 intraperitoneally 被注射。SDF-1 mRNA 表示被即时聚合酶链反应测量。组织学变化与 immunofluorescence 被分析,马森的三色的染色,并且小麦细菌凝集素。在外部血的白血球的数字被完全的血房间计数分析测量。矩阵 metalloproteinase-2/9 (MMP-2/9 ) 的活动被明胶 zymography 决定。在 infarcted 织物的 SDF-1 mRNA 的表示水平很快被提高(6 h ) ,在 24 h 达到顶点,然后在 7 天 post-MI 衰退了到正常水平。AMD3100 进一步在梗塞区域提高了 SDF-1 的增加。增加的白血球在对待 AMD3100 的组被观察。c-kit+ 干细胞和提高的 neovascularization 的动员被 AMD3100 扩充。另外, AMD3100 改进了室的改变,它被梗塞尺寸的减少揭示,可行 cardiomyocyte 代表性的区域和左室(LV ) LV 免费的墙厚度的扩大索引,和增加。MMP-2/9 的活动由 AMD3100 是起来调整的。在结论, AMD3100 的短期的断断续续的管理能在试验性的 MI 加速弯屈的愈合的过程并且是为 MI 的处理的潜在的治疗。 | Yuechen Luo Xiaoning Zhao Xin Zhou Wenjie Ji Ling Zhang Tao Luo Hongmei Liu Tigang Huang Tiemin Jiang Yuming Li | 2013 | Acta Biochimica et Biophysica Sinica2013，45，7： | 3 |
| 6 | Homing Strategy for a 4RRR Parallel Kinematic Machine显示文摘Returning home is the most important process of a parallel kinematic machine (PKM) with incremental encoders.Currently,most corresponding articles focus on the accuracy of homing process,and there lacks the investigation of the operation's safety.For a 4RRR PKM,all servoaxes would be independently driven to their zero positions at the same time based on the traditional homing mode,and that can bring serious interfere of the kinematic chains.This paper systemically investigates this 4RRR PKM's safety of homing process.A homing strategy usually contains three parts which are the home switches' locations,the platform's initial moving space,and each links' homing direction,and all of them can influence the safety of homing operation.For the purpose of evaluating and describing the safety of the homing strategy,some important parameters are introduced as follows:Safely homing ratio (SHR) is used to evaluate the probability of a machine's successfully returning home from an initial moving space;Synchronal rotational angle (SRA) is the four links' largest synchronal rotational angle with given directions from a given pose.Whether a machine can safely return home from a given pose can be judged by comparing the SRA with all four home switches' mounting angles.By meshing the initial moving space and checking the safeties of returning home from all the initial poses on the nodes,the SHR of this initial moving space can be calculate.For the sake of convenience,the platform's initial moving space should be as large as possible,and in this 4RRR PKM,a square zone in the center of the workspace with a giving initial rotation range is selected as the platform's initial moving space.The forward direction is selected as each link's homing direction according to custom,and the platform's initial rotational angle is selected as larger than 0° based on this 4RRR PKM's kinematic characteristics.The platform's initial moving space can be defined only by the side length of the initial moving square.By setting a probable searching step and calculating the SHR of the initial moving square,an optimal procedure of searching for the largest side length of the platform's initial moving square is proposed.The homing strategy proposed is based on a systemic research on the safety of homing process for PKM,and the two new indexes SHR and SRA can clearly describe the safety of homing operation.The homing operation based on this strategy is fast and safe,and the method can also be used in other PKMs with the situation of serious components' interference. | WANG Liping LIU Dawei LI Tiemin | 2011 | Chinese Journal of Mechanical Engineering2011，24，3： | 2 |
| 7 | Gankyrin promotes tumor growth and metastasis through activation of IL‐6/STAT3 signaling in human cholangiocarcinoma显示文摘 | Tongsen Zheng Xuehui Hong Jiabei Wang Tiemin Pei Yingjian Liang Dalong Yin Ruipeng Song Xuan Song Zhaoyang Lu Shuyi Qi Jiaren Liu Boshi Sun Changming Xie Shangha Pan Yuejin Li Xiaohe Luo Shuai Li Xiang Fang Nishant Bhatta Hongchi Jiang Lianxin Liu | 2014 | Hepatology2014，，： | 2 |
| 8 | Running Accuracy Analysis of a 3-RRR Parallel Kinematic Machine Considering the Deformations of the Links显示文摘Parallel kinematic machines have drawn considerable attention and have been widely used in some special fields.However,high precision is still one of the challenges when they are used for advanced machine tools.One of the main reasons is that the kinematic chains of parallel kinematic machines are composed of elongated links that can easily suffer deformations,especially at high speeds and under heavy loads.A 3-RRR parallel kinematic machine is taken as a study object for investigating its accuracy with the consideration of the deformations of its links during the motion process.Based on the dynamic model constructed by the Newton-Euler method,all the inertia loads and constraint forces of the links are computed and their deformations are derived.Then the kinematic errors of the machine are derived with the consideration of the deformations of the links.Through further derivation,the accuracy of the machine is given in a simple explicit expression,which will be helpful to increase the calculating speed.The accuracy of this machine when following a selected circle path is simulated.The influences of magnitude of the maximum acceleration and external loads on the running accuracy of the machine are investigated.The results show that the external loads will deteriorate the accuracy of the machine tremendously when their direction coincides with the direction of the worst stiffness of the machine.The proposed method provides a solution for predicting the running accuracy of the parallel kinematic machines and can also be used in their design optimization as well as selection of suitable running parameters. | WANG Liping JIANG Yao LI Tiemin | 2014 | Chinese Journal of Mechanical Engineering2014，27，5： | 2 |
| 9 | Dynamic analysis of the 2- DOF planar parallel manipulator of a heavy duty hybrid machine tool 显示文摘 | Wu Jun Wang Jinsong Li Tiemin | 2007 | The International Journal of Advanced Manufacturing Technology2007，34，12： | 1 |
| 10 | Force optimization of planar 2-DOF parallel manipulators with actuation redundancy considering deformation显示文摘 | Wu Jun Li Tiemin Xu Boqiang | | 0，，： | 1 |
| 11 | Stiffness and natural frequency of a 3-DOF parallel manipulator with consideration of additional leg candidates显示文摘 | WU Jun LI Tiemin WANG Jinsong | 2013 | Robotics and Autonomous Systems2013，61，8： | 1 |
| 12 | Analysis and application of a 2-DOF planar parallel mechanism显示文摘 | WU Jun WANG Jinsong LI Tiemin | 2007 | Journal of Mechanical Design2007，129，4： | 1 |
| 13 | Study on the stiffness of a 5-DOF hybrid machine tool with actuation redundancy显示文摘 | WANG Jinsong WANG Liping LI Tiemin | 2009 | Mechanism and Machine Theory2009，44，2： | 1 |
| 14 | Diarylquinoline compounds induce autophagy-associated cell death byinhibiting the Akt pathway and increasing reactive oxygen species in human nasopharyngealcarcinoma cells显示文摘 | Yuchen Cai Zhihui Wan Tiemin Sun Yanxia Shi Yueli Sun Peiyu Huang Su Li Wenqi Jiang | 2013 | Oncology Reports2013，，3： | 1 |
| 15 | PolyvasculaR Evaluation for Cognitive Impairment and vaScular Events (PRECISE)-a population-based prospective cohort study: rationale, design and baseline participant characteristics显示文摘Background and purpose Cardiovascular diseases and dementia are two major diseases in the elderly.Atherosclerosis is associated with future vascular events and cognitive impairment.The PolyvasculaR Evaluation for Cognitive Impairment and vaScular Events(PRECISE)study is a population-based prospective cohort study with comprehensive evaluation of multiterritorial artery stenosis and plaque using advanced vascular imaging techniques and prospective collection of vascular events and cognitive assessments.Methods Between May 2017 and September 2019,the PRECISE study enrolled 3067 community-dwelling adults with ages between 50 and 75 years cluster sampled from six villages and four communities of Lishui city in China.Data are collected in face-to face interviews at baseline,2-year and 4-year follow-up visits.Brain MRI including high-resolution sequences for intracranial and carotidal arteries and CT angiography for thoracoabdominal arteries were performed at baseline and will be rescanned after 4 years.Cardiovascular/cerebrovascular events and cognitive assessment will be prospectively collected after the enrollment.Blood and urine samples were collected and biomarkers were tested at baseline.Results A total of 3067 subjects were enrolled,among which 53.5%were female with an average age of 61.2±6.7 years.Among them,2.8%,8.1%,43.1%and 21.6%had a history of stroke,coronary heart diseases,hypertension and diabetes mellitus,respectively.Conclusions The PRECISE study is a population-based prospective cohort study with comprehensive evaluation of atherosclerotic stenosis and plaque using advanced vascular imaging techniques.Data from this cohort provide us an opportunity to precisely evaluate polyvascular atherosclerosis and its association with future vascular events and cognitive impairment. | Yuesong Pan Jing Jing Xueli Cai Yilong Wang Suying Wang Xia Meng Chunlai Zeng Jiong Shi Jiansong Ji Jinxi Lin Lingchun Lyu Zhe Zhang Lerong Mei Shiping Li Shan Li Wanlin Zhu Hao Li Tiemin Wei Yongjun Wang | 2021 | Stroke & Vascular Neurology2021，6，1： | 1 |
| 16 | Dynamic dexterity of a planar 2-DOF parallel manipulator in a hybrid machine tool显示文摘 | WU Jun WANG Jinsong LI Tiemin | 2007 | Robotica2007，26，1： | 1 |
| 17 | Geometric error modeling of machine tools based on screw theory显示文摘 | Zhao Yu Li Tiemin Tang Xiaoqiang | 2011 | Procedia Engineering2011，，24： | 1 |
| 18 | Thermal sensor selection for the thermal error modelingof machine tool based on the fuzzy clustering method显示文摘 | WANG Haitong WANG Liping LI Tiemin | 2013 | International Journal of Advanced ManufacturingTechnology2013，69，14： | 1 |
| 19 | Dynamic formulation of redundant and nonredundant parallel manipulators for dynamic parameter identification显示文摘 | Jun Wu Jinsong Wang Liping Wang Tiemin Li | 2009 | Mechatronics2009，，4： | 1 |
| 20 | Dynamics and control of a planar 3-DOF parallel manipulator with actuation redundancy显示文摘 | Jun Wu Jinsong Wang Liping Wang Tiemin Li | 2008 | Mechanism and Machine Theory2008，，4： | 1 |
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