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Type Synthesis of Two-Degrees-of-Freedom Rotational parallel Mechanism with Two Continuous Rotational Axes

Chinese Journal of Mechanical Engineering 2016年第4期29卷 694-702页

作者： XU Yundou ZHANG Dongsheng WANG Min YAO Jiantao ZHAO Yongsheng Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan University Key Laboratory of Advanced Forging and Stamping Technology and Science of Ministry of National Education Yanshan University Library Yanshan University

The two-rotational-degrees-of-freedom（2R） parallel mechanism（PM） with two continuous rotational axes（CRAs） has a simple kinematic *** is therefore easy to implement trajectory planning,parameter calibration,and motion control,which allows for a variety of application ***,no systematic analysis on structural constraints of the 2R-PM with two CRAs has been performed,and there are only a few types of 2R-PM with two ***,a theory regarding the type synthesis of the 2R-PM with two CRAs is systematically ***,combining the theories of reciprocal screw and space geometry,the spatial arrangement relationships of the constraint forces applied to the moving platform by the branches are explored,which give the 2R-PM two *** different distributions of the constraint forces in each branch are also *** the basis of the obtained structural constraints of branches,and considering the geometric relationships of constraint forces in each branch,the appropriate kinematic chains are *** the reasonable configuration of branch kinematic chains corresponding to every structural constraint,a series of new 2R-PMs with two CRAs are finally obtained.

关键词： type synthesis continuous rotational axes two rotational degrees of freedom parallel mechanism constraint force

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Stiffness analysis of a planar 3-RPS parallel manipulator

Lecture Notes in Mechanical Engineering

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Lecture Notes in Mechanical Engineering 2017年 13-28页

作者： Hu, Bo Song, Chunxiao Li, Bo Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan University QinhuangdaoHebei066004 China Key Laboratory of Advanced Forging and Stamping Technology and Science of Ministry of National Education Yanshan University QinhuangdaoHebei066004 China

This paper studied the stiffness model and characteristics of a planar 3-RPS PM with 3-DOF. The 6 × 6 form stiffness matrix of the planar 3-RPS PM is derived with both active and constrained wrenches considered. To characteristic the stiffness of the planer 3-RPS PM, two decomposition methods including the eigenscrew decomposition and the principle axes decomposition are applied to the stiffness matrix. The stiffness matrix decomposition provides a physical interpretation and allows the identification of the compliant axes of the planar 3-RPS PM. © Springer International Publishing Switzerland 2017.

关键词： Stiffness

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Global Dynamic Modeling of Electro-Hydraulic 3-UPS/S parallel Stabilized Platform by Bond Graph

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Chinese Journal of Mechanical Engineering 2016年第6期29卷 1176-1185页

作者： ZHANG Lijie GUO Fei LI Yongquan LU Wenjuan Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Yanshan University Key Laboratory of Advanced Forging & Stamping Technology and Science of Ministry of Education Yanshan University Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan University

Dynamic modeling of a parallel manipulator（PM） is an important issue. A complete PM system is actually composed of multiple physical domains. As PMs are widely used in various fields, the importance of modeling the global dynamic model of the PM system becomes increasingly prominent. Currently there lacks further research in global dynamic modeling. A unified modeling approach for the multi-energy domains PM system is proposed based on bond graph and a global dynamic model of the 3-UPS/S parallel stabilized platform involving mechanical and electrical-hydraulic elements is built. Firstly, the screw bond graph theory is improved based on the screw theory, the modular joint model is modeled and the normalized dynamic model of the mechanism is established. Secondly, combined with the electro-hydraulic servo system model built by traditional bond graph, the global dynamic model of the system is obtained, and then the motion, force and power of any element can be obtained directly. Lastly, the experiments and simulations of the driving forces, pressure and flow are performed, and the results show that, the theoretical calculation results of the driving forces are in accord with the experimental ones, and the pressure and flow of the first limb and the third limb are symmetry with each other. The results are reasonable and verify the correctness and effectiveness of the model and the method. The proposed dynamic modeling method provides a reference for modeling of other multi-energy domains system which contains complex PM.

关键词： screw bond graph multi-energy domains 3-UPS/S parallel mechanism electro-hydraulic servo system

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Error modeling for the leg mechanism of the quadruped walking chair robot

Error modeling for the leg mechanism of the quadruped walkin...

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International Conference on Applied system Innovation, ICASI 2015

作者： Wang, H.B. Wang, S.S. Wen, Y.H. Chen, N. Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan University QinhuangdaoHeBei Province China Key Laboratory of Advanced Forging and Stamping Technology and Science Yanshan University QinhuangdaoHeBei Province China

ISBN: (纸本)9781138028937

To reduce the output error of the parallel robot, it is crucial to analyze the pose error of the parallel mechanism. This paper deals with the pose error analysis, and establishes the model for the effects of pose parameters and structural parameters on the accuracy of the leg mechanism. Firstly, based on the research of constraint relations on the leg mechanism of the walking chair robot, the error model is established. Then the influence of structure parameters and pose parameters on the pose error is studied. The results contribute a lot to the determination of the structural parameters and the output error of the control system. © 2016 Taylor & Francis Group, London.

关键词： Errors

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Analysis of Multi-axes Adjustment Platform for Tunnel Intelligent Detection system

Analysis of Multi-axes Adjustment Platform for Tunnel Intell...

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2017 2nd International Conference on Automation, Mechanical and Electrical Engineering (AMEE2017)

作者： Xiao Liu Jie Zhang Erjuan Luo Menghua Liu Yingjie Duan Pengbo Li Chunming Xue Key Lab of highway Construction & Maintenance Technology in Loess Region Shanxi Transportation Research Institute Liren College of Yanshan University Hebei Provincial Key Lab of Parallel Robot and Mechatronic System Yanshan University

Based on the key technology problems of the tunnel intelligent detection system, this paper proposes a method of using multi-axes adjustment platform to solve the problem of image acquisition. The design method of multi-axes adjustment platform is proposed and a new type of 3-DOF parallel mechanism is designed. On the basis of kinematic analysis, the mapping between the input and output of the multi-axes adjustment platform is established, and the constraint conditions of workspace of the mechanism are defined. Finally,a design of servo control scheme and hardware selection of the experimental prototype is carried out. In order to test and validate the model, the experimental tests are put forward, and the workspace of the system is analyzed. This paper applies the robot technology to the field of machine vision, and offered a new method for developing tunnel intelligent detection system.

关键词： multi-axes adjustment platform 3-DOF parallel mechanism mechanism model tunnel rapid detection system

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Effect of Rolling Reduction Rate on the Microstructure of Hot Rolling Stainless Steel Clad Plate

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IOP Conference Series: Materials Science and Engineering 2018年第3期394卷

作者： Herong Jin Lei Zhang Yali Yi Key Laboratory of Advanced Forging & Stamping Technology and Science of Ministry of National Education Yanshan University Qinhuangdao 066004 China Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan University Qinhuangdao 066004 China School of Mechanical Engineering Yanshan University Qinhuangdao 066004 China

The macro-scale and meso-scale simulation models of stainless steel clad plate were established by DEFORM-3D. The multi-scale coupling simulations of clad plate with different rolling parameters were carried out. The seven pass hot rolling process of stainless steel clad plate was simulated by numerical simulation. By contrasting the vertical stress and the deformation resistance of cladding layer, the rolling reduction rate satisfying interface bonding was obtained. The grain distribution at the center of the substrate layer was analyzed and reasonable hot rolling reduction rates were selected considering their effects on the recrystallization volume percent and the grain size. The results show that the grain size decreases with the increase of reduction rate. However, too much reduction rate will decrease the rate of recrystallization volume percent and the refining effect of grain is not obvious. To ensure uniform grain size distribution, it is most reasonable to set the rolling temperature to 1150°C and the reduction rate to 50%.

关键词：

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Continuous motion of a novel 3-CRC symmetrical parallel mechanism

Continuous motion of a novel 3-CRC symmetrical parallel mech...

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作者： Chen, Ziming Cao, Wen-Ao Ding, Huafeng Huang, Zhen School of Mechanical Engineering Yanshan University Qinhuangdao066004 China Hebei Provincial Key Laboratory of Parallel Robot and Mechatronic System Yanshan University Qinhuangdao China Faculty of Mechanical and Electronic Information China University of Geosciences Wuhan China

parallel mechanisms (PMs) with three degrees of freedom (DOFs) have been studied extensively, especially the PMs with two rotational and one translational DOFs (2R1T PMs). One major problem of the 2R1T PMs is the inherent parasitic motion. In this paper, a novel 2R1T symmetrical parallel mechanism with no parasitic motion is proposed and studied. The moving platform and the base of this mechanism are mirror symmetric with respect to a mid-plane. This moving platform can realize continuous rotation about any axis or any point on the mid-plane and can have continuous translation along the normal line of the mid-plane. The constraint and motion characteristics of this mechanism are analyzed. The kinematics solutions and the Jacobian matrix are derived. The singularities of this PM are discussed. In the end, several numerical examples are given to show the continuous rotations and continuous translations of this PM. This kind of PMs has outstanding advantages of easy path planning and controlling. © 2014 Institution of Mechanical Engineers.

关键词： Jacobian matrices

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Deployable unit 3R-3URU and its application in deployable truss antenna

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Hangkong Xuebao/Acta Aeronautica et Astronautica Sinica 2017年第11期38卷 421285页

作者： Liu, Wenlan Xu, Yundou Yao, Jiantao Chen, Liangliang Wang, Hui Zhao, Yongsheng Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan University Qinhuangdao066004 China Key Laboratory of Advanced Forging & Stamping Technology and Science of Ministry of Education Yanshan University Qinhuangdao066004 China Xi'an710100 China

A spatial deployable unit 3R-3URU with one Degree of Freedom (DoF) is proposed. The DoF of the single closed-loop mechanism RURUR is analyzed, based on the screw theory and the modified G-K formula. The analytical expression for the velocities of active joints and passive joints of the mechanism RURUR are then established. According to the velocity expression and the structural characteristic that three RURUR mechanisms share their first and last revolute joints, the DoF of the 3R-3URU mechanism is derived. The geometrical relationship among the positions and directions of all joints is also obtained when the 3R-3URU mechanism has one DoF. Novel deployable mechanisms are obtained by applying the 3R-3URU mechanism to the 3RR-3RRR tetrahedral unit and a deployable truss antenna composed of the tetrahedral units, and the novel mechanisms have two types of DoFs: movement and orientation adjustment. DoF analysis and application of the 3R-3URU deployable unit are verified by the Adams software. The proposed deployable unit 3R-3URU has the advantages of one DoF, simple structure, and single type of joints, and can be applied to the supporting mechanism of deployable truss antennas with a curved surface to achieve a large folding ratio. © 2017, Press of Chinese Journal of Aeronautics. All right reserved.

关键词： Degrees of freedom (mechanics)

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Mobility analysis of a deployable truss-antenna mechanism-Method based on link-demolishing and equivalent idea

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Hangkong Xuebao/Acta Aeronautica et Astronautica Sinica 2017年第9期38卷 421188页

作者： Xu, Yundou Liu, Wenlan Chen, Liangliang Yao, Jiantao Zhao, Yongsheng Zhu, Jialong Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan University Qinhuangdao066004 China Key Laboratory of Advanced Forging & Stamping Technology and Science of Ministry of National Education Yanshan University Qinhuangdao066004 China Xi'an710100 China

A method for Degree Of Freedom (DOF) analysis of spatial mechanisms with multiple coupled-loops is proposed based on the link-demolishing and equivalent idea, in view of the multi-loop coupling characteristic of a deployable truss antenna assembled by tetrahedral elements. The coupling constraint chain of the deployable tetrahedral element is removed, and the remainder is regarded as a parallel mechanism. The number and characteristic of the DOF of each output node are then analyzed using the screw theory, and the equivalent serial kinematic chain between the output nodes and the fixed node are then established. The equivalent mechanism of the deployable tetrahedral element is obtained by reconstructing the coupling constrained chain. The number and characteristic of the DOF of the equivalent mechanism are got using the modified G-K formula and the reciprocal screw theory, respectively. As a result, the kinematic characteristics of the tetrahedral element are known. The structure of the minimum composite unit and the large-scale truss deployable antenna are simplified, according to the equivalent mechanism and the combination of the tetrahedral elements. The numbers of the DOF of the minimum composite unit and the large-scale truss deployable antenna are derived on the basis of the geometric constraint equations. The simulation model for a deployable truss antenna assembled by 27 tetrahedral elements is built, and its DOF is verified. The result shows that the DOF of the antenna analyzed by the proposed method is correct. The method lays a foundation for further analysis of the kinematics and dynamics of similar type of antennas, providing a new idea for DOF analysis of other multi-loop coupling mechanisms. © 2017, Press of Chinese Journal of Aeronautics. All right reserved.

关键词： Antennas

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Effects of heat treatment on microstructure and properties of stainless clad plate

Effects of heat treatment on microstructure and properties o...

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International Conference on Advanced Materials and Engineering Materials, ICAMEM 2016

作者： Jin, Herong Yang, Xukun Cui, Youwei Yi, Yali Key Lab. of Advanced Forging and Stamping Technology and Science of Ministry of National Education Yanshan University Qinhuangdao China Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan University Qinhuangdao China School of Mechanical Engineering Yanshan University Qinhuangdao China

ISBN: (纸本)9783038357018

The effect of heat treatment on microstructure and properties of Q345R/304 clad plate was studied. The microstructure of the base layer was analyzed by metallographic microscope and scanning electron microscope, and mechanical properties such as tensile, shear and impact were investigated after heat treatment. The chromium content in the compound interface was analyzed after heat treatment through spectrum analysis technology. The results show that heat treatment affects the mechanical properties and corrosion resistance of stainless clad plate significantly. After air cooling, the microstructure of the base layer consi+sts of ferrite and pearlite, the strength of clad plate is low, and the corrosion resistance is poor. After oil cooling to 450°C and air cooling, the microstructure of the base layer consists of bainite, ferrite and a small amount of pearlite. The strength and plasticity of clad plate can meet the application requirements and the corrosion resistance is excellent as well. © 2016 Trans Tech Publications, Switzerland.

关键词： Microstructure

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