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| 1 | Type Synthesis of 1T2R Parallel Mechanisms Using Structure Coupling-Reducing Method显示文摘Direct kinematics with analytic solutions is critical to the real-time control of parallel mechanisms.Therefore,the type synthesis of a mechanism having explicit form of forward kinematics has become a topic of interest.Based on this purpose,this paper deals with the type synthesis of 1T2R parallel mechanisms by investigating the topological structure coupling-reducing of the 3UPS&UP parallel mechanism.With the aid of the theory of mechanism topology,the analysis of the topological characteristics of the 3UPS&UP parallel mechanism is presented,which shows that there are highly coupled motions and constraints amongst the limbs of the mechanism.Three methods for structure coupling-reducing of the 3UPS&UP parallel mechanism are proposed,resulting in eight new types of 1T2R parallel mechanisms with one or zero coupling degree.One obtained parallel mechanism is taken as an example to demonstrate that a mechanism with zero coupling degree has an explicit form for forward kinematics.The process of type synthesis is in the order of permutation and combination;therefore,there are no omissions.This method is also appli cable to other configurations,and novel topological structures having simple forward kinematics can be obtained from an original mechanism via this method. | Haitao Liu Ke Xu Huiping Shen Xianlei Shan Tingli Yang | 2019 | Chinese Journal of Mechanical Engineering2019，32，5： | 9 |
| 2 | Type synthesis of a class of spatial lower-mobility parallel mechanisms with orthogonal arrangement based on Lie group enumeration显示文摘Type synthesis of lower-mobility parallel mechanisms (PMs) has drawn extensive interests, particularly two main approaches were established by using the reciprocal screw system theory and Lie group theory, respectively. Although every above approach provides a universal framework for structural design of general lower-mobility PMs, type synthesis is still a comparably difficult task for the PMs with particular geometry or required to fulfill some specified tasks. This paper aims at exploring a simple and effective synthesis method for lower-mobility parallel mechanisms with orthogonal arrangement (OPMs), and the applied mathematical tool is established in the displacement group theory. For this purpose, the concept of the Cartesian DOF-characteristic matrix, originated from canonical displacement subgroup and displacement submanifold, is proposed. A new approach based on combination of the atlas of Cartesian DOF-characteristic matrix and displacement group-theoretic method is addressed for both exhaustive classification and type synthesis of OPMs. Type synthesis for some representatives of 3-DOF OPMs verifies effectiveness of the proposed approach. | DAI Jian S. | 2010 | Science China(Technological Sciences)2010，53，2： | 7 |
| 3 | Type Synthesis of Lower Mobility Parallel Mechanisms: A Review显示文摘Type synthesis of mechanisms aims to systematically determine all possible structures for a specific mobility requirement. Numerous methods based on di erent theories were proposed for type synthesis of lower mobility parallel mechanisms in past decades. However, there does not exist a comprehensive review on these approaches. Therefore, the goal of this paper is to give such a review, classifying the approaches proposed in the literature into three groups, namely, motion-based methods, constraint-based methods, and other methods. The motion-based methods include the Lie group based method, the GF set method, the linear transformation method, the POC set method,and the finite screw method. The constraint-based methods involve the screw theory-based method, the virtual chain method, the method based on Grassmann line geometry and line graphs, and the motion constraint generator method. Other methods contain the enumeration approach based on the general CGK mobility formula and the graph theory method. Upon thoroughly analyzing the characteristics and/or limitations of each method, this review provides a well reference to help researchers find an e ective synthesis method for innovative design and further scientific investigations for mechanisms. | Wei Ye Qinchuan Li | 2019 | Chinese Journal of Mechanical Engineering2019，32，2： | 6 |
| 4 | Type synthesis of 2-DoF rotational parallel mechanisms actuating the inter-satellite link antenna显示文摘This paper focuses on the type synthesis of two degree-of-freedom(2-DoF) rotational parallel mechanisms(RPMs) that would be applied as mechanisms actuating the inter-satellite link antenna. Based upon Lie group theory, two steps are necessary to synthesize 2-DoF RPMs except describing the continuous desired motions of the moving platform. They are respectively generation of required open-loop limbs between the fixed base and the moving platform and definition of assembly principles for these limbs. Firstly, all available displacement subgroups or submanifolds are obtained readily according to that the continuous motion of the moving platform is the intersection of those of all open-loop limbs. These subgroups or submanifolds are used to generate all the topology structures of limbs. By describing the characteristics of the displacement subgroups and submanifolds intuitively through employing simple geometrical symbols, their intersection and union operations can be carried out easily. Based on this, the assembly principles of two types are defined to synthesize all 2-DoF RPMs using obtained limbs. Finally, two novel categories of 2-DoF RPMs are provided by introducing a circular track and an articulated rotating platform,respectively. This work can lay the foundations for analysis and optimal design of 2-DoF RPMs that actuate the inter-satellite link antenna. | Song Yimin Qi Yang Dong Gang Sun Tao | 2016 | Chinese Journal of Aeronautics2016，29，6： | 3 |
| 5 | Type Synthesis and Kinematics Performance Analysis of a Class of 3T2R Parallel Mechanisms with Large Output Rotational Angles显示文摘Based on Lie group theory and the integration of configuration, a class of 3T2 R(T denotes translation and R denotes rotation) parallel mechanisms with large output rotational angles is synthesized through a five degree of freedom single limb evolving into two five degree of freedom limbs and constraint coupling of each kinematics chain. A kind of 3T2 R parallel mechanisms with large rotational angles was selected from type synthesis of 3T2 R parallel mechanisms, inverse kinematics and velocity Jacobian matrix of the parallel mechanism are established. The performance indices including workspace, rotational capacity, singularity and dexterity of the parallel mechanism are analyzed. The results show that the parallel mechanism has not only large output rotational angles but also better dexterity. | Bing-Shan Jiang Hai-Rong Fang Hai-Qiang Zhang | 2019 | International Journal of Automation and computing2019，16，6： | 2 |
| 6 | SYNTHESIS AND CHARACTERIZATION OF NOVEL CHIRAL SMECTIC C(Sc~*) PHASE SHISH-KEBAB TYPE LIQUID CRYSTALLINE BLOCK COPOLYMERS显示文摘A new series of chiral shish-kebab type liquid crystal block copolymers that form the smecticC(Sc~*) phase was synthesized by solution polycondensation. The copolymers were characterized by GPC.DSC. TG, POM. X-ray diffraction and polarimeter. The copolymers 7 entered into liquid crystal phase whenthey were heated to their melting temperatures (T_m) and the copolymers 8 were in liquid crystal phase at roomtemperature with low viscosities. The smectic sanded texture or focal-conic texture were observed on POM.All the chiral block copolymers showed high optical activity. No racemization has happened. Temperature-variable X-ray diffraction study together with POM and polarimetric analysis realized that they are chiralsmectic C(Sc~*) phase. Thus we offer in this report the first example of shish-kebab type liquid crystal blockcopolymers that form a chiral smectic C(Sc~*) phase. The variation of melting and isotropization temperatureswith molecular structure was also discussed. | 周其凤 | 1999 | Chinese Journal of Polymer Science1999，17，6： | 0 |
| 7 | Synthesis of Polymer-Bonded Quaternary Ammonium Type Metal Porphyrins显示文摘The reaction of pyrrole with 4-hydroxybenzaldehyde and 4-pyridinecarboxaldehyde afforded new porphyrin ligand 1. Treatment of I with copper(II ) acetate, cobalt (II ) acetate gave complexes 2-3 respectively. 2 and 3 reacted with Merrifield’s peptide resin produced 4 and 5. Complexes 4 and 5 reacted with methyl iodide respectively gave 6-7. The new compounds l-7 have been identified by 1H NMR, IR, MS and UV-visible spectra, elemental analysis and AES. | Zao Ying LI Cong LI Xu Ye WU( Department of Chemistry, Wuhan University, Wuhan 430072) | 2000 | Chinese Chemical Letters2000，11，1： | 0 |
| 8 | Synthesis,Proton Conductivity and Humidity Sensing Property of γ-Type Zirconium Hydrogen Phosphate,Zr(HPO_4)_2·2H_2O显示文摘IntroductionFastprotonconductorshavebeenstudiedforseveraldecadesduetotheirapplicationstolowtemperaturefuelcelsandhumiditysens... | FENG Shou hua ** , ZHAO Hui and LI Lian sheng (Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun 130023) Martha Greenblatt (Department of Chemistry, Rutgers, the State University of New Jersey, Piscat | 1999 | Chemical Research in Chinese Universities1999，15，1： | 0 |
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