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Research Square 2021年

作者： Li, Shihua Wang, Sen Li, Haoran Wang, Yongjie Chen, Shuang Hebei Provincial Key Laboratory of Parallel Robot and Mechatronic Systems Yanshan University China School of Mechanical Engineering Yanshan University Qinhuangdao066004 China

In this paper, a new synthesis method of fully decoupled three translational (3T) parallel mechanisms (PMs) with closed-loop units and high stiffness is proposed based on screw theory. Firstly, a new criterion for the full decoupled of PMs is presented that the reciprocal product of the transmission wrench screw matrix and the output twist screw matrix of PMs is a diagonal matrix, and all elements on the main diagonal are nonzero constants. The forms of the transmission wrench screws are determined by the criterion. Secondly, the forms of the actuated and unactuated screws can be obtained according to their relationships with the transmission wrench screws. The basic decoupled limbs are generated by combination of the above actuated and unactuated screws. Finally, a closed-loop units construction method is investigated to apply the decoupled mechanisms in a better way on the high stiffness occasion. The closed-loop units are constructed in the basic decoupled limbs to generate a high-stiffness fully decoupled 3T PM. Kinematic and stiffness analyses show that the Jacobian matrix is a diagonal matrix, and the stiffness is obviously higher than that of the orthogonal coupling mechanisms, which verifies the correctness of the proposed synthesis method. The mechanism synthesized by this method has a good application prospect in vehicle durability test platform. © 2021, CC BY.

关键词： Stiffness

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Semantic Segmentation of Surgical Instruments based on Enhanced Multi-scale Receptive Field

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Journal of Physics: Conference Series 2021年第1期2003卷

作者： Dong, Yu Wang, Hongbo Luo, Jingjing Lai, Zhiping Wang, Fuhao Wang, Jiawei Academy for Engineering and Technology Fudan University Shanghai200433 China Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan University Qinhuangdao066004 China Intelligent Robot Engineering Research Center Ministry of Education Shanghai200433 China Shanghai Intelligent Robot Engineering Technology Research Center Shanghai200433 China

With the rapid development of robot assisted surgery, the segmentation of surgical instruments becomes more and more important. However, compared with the natural scene segmentation, surgical instrument segmentation is more difficult. To solve this problem, we improve a high and low resolution fusion module, which aims to extract detail information and context information from the fusion feature map of high and low resolution. Then, in the last layer of the encoder, we propose the Enhanced Multi-scale Receptive Field module to generate more available receptive fields. Our method is validated on 2017 MICCAI EndoVis robotic Instrument Segmentation Challenge dataset, and the result is better than the other methods. The extended experiment is carried out on the dataset of our surgical soft robot which has a content implementation. © Published under licence by IOP Publishing Ltd.

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A low-cost passenger safety protection system based on laser ranging

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Journal of Physics: Conference Series 2021年第1期2003卷

作者： Wang, Fuhao Wang, Hongbo Zhang, Xueze Dong, Yu Lai, Zhiping Wang, Jiawei Academy for Engineering and Technology Fudan University Shanghai200433 China Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan University Qinhuangdao066004 China Intelligent Robot Engineering Research Center Ministry of Education Shanghai200433 China Shanghai Intelligent Robot Engineering Technology Research Center Shanghai200433 China

In 2021, the total number of motor vehicles in China has exceeded 370 million. In the process of getting off the car, avoiding accidents between passengers and non-motor vehicles is of great significance for reducing casualties and economic losses. Therefore, this paper designs a low-cost passenger safety protection system based on laser ranging. Following the principle of easy integration and miniaturization, the hardware design and software design of the system have been completed. The mathematical model of arrival time-distance of non-motor vehicle under various speeds is established. Laser-ranging data is used to build the map, and the map can be used for non-motor vehicle identification and speed estimation. The function and precision of the system are tested. The experimental results show that 1) the established model can automatically determine whether passengers can get off the car safely and close the door in dangerous situations;2) the mapping method based on laser ranging can effectively distinguish between non-motorized vehicles and roadsides. The accuracy of non-motor vehicle speed measurement is about 90%. The designed passenger safety protection system has high practicability. © Published under licence by IOP Publishing Ltd.

关键词： laser ranging mapping safety protection Traffic accident

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A Calibration Method for parallel robot Based on Eye in Hand Vision

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Zhongguo Jixie Gongcheng/China Mechanical Engineering 2020年第6期31卷 722-730and755页

作者： Li, Yongquan Wang, Haochen Zhang, Yang Zhang, Yan Zhang, Lijie Hebei Provincial Key Laboratory of Parallel Robot and Mechatronic System Yanshan University QinhuangdaoHebei066004 China Ministry of Education QinhuangdaoHebei066004 China Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Yanshan University QinhuangdaoHebei066004 China

A calibration method of parallel robots was proposed based on eye in hand vision. Firstly, based on the loop increment method, the kinematics errors and calibration model of a planar 2-DOF redundant actuated parallel robot were established. Secondly, a target plate was designed for the calibration experiments, and the target image was captured by the camera and processed by the segmentation, recognition and rotation compensation, and then the pixel error values of the end positions and the actual positions of the mechanisms were obtained. Thirdly, limited by the structures of the mechanisms, using the boundary curve to identify the feature corner points, a method was proposed to determine the rotation angles of the detection point based on the feature corner points. On the basis of compensating the rotation angles of the camera, using a simplified model of the camera pinhole, the error values of the pixel errors were converted to the true position error values of the ends of the mechanisms. Finally, the calibration model and the error values obtained through the visual system were used for kinematics calibration. After 4 iterations, the errors of the mechanisms are decreased to 1/3, which verifies the feasibility of the robots. The proposed method has the advantages of short time of calibrations, small amount of data and low cost of experiments. © 2020, China Mechanical Engineering Magazine Office. All right reserved.

关键词： Kinematics

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Dynamics of Passive-input Overconstrained Deployable Antenna Mechanisms Composed of 3RR-3RRR Tetrahedron Units

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Jixie Gongcheng Xuebao/Journal of Mechanical Engineering 2020年第5期56卷 181-191页

作者： Liu, Wenlan Xu, Yundou Guo, Jinwei Yao, Jiantao 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 National Education Yanshan University Qinhuangdao066004 China

The dynamic model of a passive-input overconstrained deployable antenna mechanism composed of 3RR-3RRR tetrahedron units is established, and the effects of the number, stiffness and initial compression angle of driving elements (i.e., torsion springs) on the motion of mechanism are analyzed. Based on the structural characteristics and spatial coordinate transformation formulas the relationships between the positions of the centroid of each component and the independent deployment angle of the mechanism are deduced, and then the analytical expressions of velocities of all components are obtained. The movements of all components are divided into translation motion, fixed-axis rotation, plane motion and compound motion according to the characteristic of the degree of freedom (DOF) of the mechanism. For the sake of dynamic analysis of the passive-input overconstrained mechanism, the composite motion of components is further decomposed into plane motion and translation motion along the normal direction of the plane. The dynamic models of the passive-input overconstrained deployable mechanism 3RR-3RRR and its combined mechanism 3(3RR-3RRR)-3RRR-3RRR are built by using Lagrange method. The relationships between the stiffness of torsion springs and the independent deployable angle of the mechanisms are obtained, and the influence of the stiffness and number of torsion springs on the deployable motion of the mechanisms is analyzed. The simulation model of 3(3RR-3RRR)-3RRR-3RRR mechanism is established by Adams software. The simulation is carried out by adding torsion springs with different numbers and stiffness. In addition, the effect of initial compression angle of torsion springs on the deployable motion of the mechanism is discussed. The simulation results verify the correctness of theoretical analyses. The results can provide theoretical guidance for the coordinated control of passive-input overconstrained deployable antenna mechanisms composed of 3RR-3RRR tetrahedron u

关键词： Stiffness

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Configuration design and motion performance analysis of a new wheeled rolling robot

Research Square

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Research Square 2021年

作者： Bian, Hui Zhang, Chun Wang, Shi-Jie Li, Jia-Chen Xie, Xue-Lei Guan, Wen-Bo Mechanical and Electronic Engineering Yanshan University China Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan University Qinhuangdao066004 China Ministry of Education Qinhuangdao066004 China Beijing Institute of Mechanical Equipment Beijing100080 China

A new wheeled rolling robot is designed based on planar 3-RRR parallel mechanism and spoke wheel with variable diameter, by adjusting the 3-DOF outputs of the planar 3-RRR parallel mechanism, the deformation and rolling motion of the rolling robot are realized, the rotation output of the parallel mechanism realizes the differential change of the diameter of the two supporting wheels of the rolling robot, and the moving output of the parallel mechanism changes the mass distribution of the system, so that the rolling robot can complete the forward, backward, turning and other motions. Based on the introduction of the performance parameters, driving system, variable diameter wheel configuration and motion mechanism of the rolling robot, the eccentric driving torque is analysis and the existing space of the eccentric torque is given, so as to further complete the selection of the driving motor of the robot. This article analysis three typical motions of robots and its performance parameters, such as straight movement, turn movement, climbing exercise, and builds a simple prototype under laboratory conditions to verify the feasibility of the three movements. © 2021, CC BY.

关键词： Wheels

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Type Synthesis of 3-Translational Redundant Actuated parallel Mechanisms With Closed-Loop Branch Chains Based On Graphical Approach

Research Square

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Research Square 2021年

作者： Li, Yong-Quan Jiang, Hong-Sheng Zheng, Tian-Yu Xi, Ke-Long Jing, Han Zhang, Li-Jie Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan University Qinhuangdao066004 China Key Laboratory of Advanced Forging & Stamping Technology and Science Ministry of Education of China Yanshan University Qinhuangdao066004 China Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Yanshan University Qinhuangdao066004 China

The 3-translational parallel mechanism is widely used in industrial, medical, and military fields, among others. With the development of the national logistics industry, a pressing need for a kind of 3-translational parallel mechanism emerged. Such mechanisms have high stiffness and high bearing capacity and are used for cargo handling and sorting. A novel method based on the graphical approach was proposed for the synthesis of 3-translational redundancy actuated parallel mechanism with closed-loop branch chains. The new mechanism has four symmetrically arranged branch chains, which eases subsequent kinematics and dynamics analyses while providing good mechanical properties. Based on the graphical approach theory, according to the constraint number contained in the branch chain, two types of redundant driven branch chains with closed-loop structures were constructed. The first type includes rotation constraint in one direction, while the second type includes the rotation constraint in two directions. Based on various combinations of two branch chain types, their allocation schemes can be divided into two types. Moreover, said these two allocation schemes can be integrated into at least 500 and 400 types of 3-translational redundant actuated parallel mechanisms with closed-loop branch chains. Then, the degree of freedom properties of representative mechanisms were tested using the screw theory. A large number of novel mechanisms were integrated assessed using this method, and branch chains such mechanisms were symmetrically distributed. They have a strong bearing capacity, simple calculation, and control, and can be applied to the handling and sorting of goods, large-scale precision machine tools, and large construction machinery vibration isolation systems, among others. © 2021, CC BY.

关键词： Redundancy

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Design and Analysis of a New 5-DOF Hybrid Serial-parallel Manipulator

Design and Analysis of a New 5-DOF Hybrid Serial-Parallel Ma...

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作者： Xu, Yundou Xu, Zhenghe Yang, Fan Mei, Youen Yue, Yi Zhou, Yulin Yao, Jiantao Zhao, Yongsheng Laboratory of Parallel Robot and Mechatronic System of Hebei Province Yanshan University Qinhuangdao066004 China Key Laboratory of Advanced Forging & Stamping Technology and Science Yanshan University Qinhuangdao066004 China Shanghai Aerospace Equipment Manufacture Company Limited Shanghai201100 China School of Mechanical Engineering Yanshan University Qinhuangdao066004 China

In this paper, a 2R1T (two rotations and one translation) over-constrained parallel mechanism R(2RPR)R/SP with two ordered continuous rotational axes is proposed, which contains fewer joints, by concatenating a 2-degree-of-freedom (DOF) RR tilting head with orientation-adjusting capability, a novel 5-DOF hybrid manipulator is constructed. On this basis, optimize the sizes with the best performance of the motion/force transmissibility as the optimization target, and the design dimensions that meet the requirements of the workspace are obtained and the structural design is carried out. The static stiffness of the manipulator are analyzed, and the analysis results are verified by simulation and compared with the products that have been successfully applied in foreign countries. An iterative searching method is used to determine the workspace of the manipulator, and evaluate whether the workspace of the hybrid manipulator meets the requirements. © 2020, Springer Nature Singapore Pte Ltd.

关键词： Manipulators

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Design and analysis of a truss deployable antenna mechanism based on a 3UU-3URU unit

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Chinese Journal of Aeronautics 2019年第12期32卷 2743-2754页

作者： Yundou XU Jinwei GUO Luyao GUO Wenlan LIU Jiantao YAO Yongsheng ZHAO Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan UniversityQinhuangdao 066004China Key Laboratory of Advanced Forging&Stamping Technology and Science of Ministry of National Education Yanshan UniversityQinhuangdao 066004China College of Energy and Power Engineering Lanzhou University of TechnologyLanzhou 730050China

Space deployable structures with large calibers, high accuracy, and large folding ratios are indispensable equipment in the aerospace field. Given that the single-DOF 3 RR-3 RRR deployable unit cannot be fully folded, this study proposes a 3 UU-3 URU deployable unit with two kinds of DOF: folding movement and orientation adjustment. First, based on the G-K formula, the DOF of the 3 UU-3 URU unit is analyzed. Then, the 3 UU-3 URU unit is used to construct a deployable truss antenna with a curved surface, and the DOF of the whole deployable antenna containing multiple 3 UU-3 URU units is calculated. The structural design of a deployable antenna with two loops is carried out with specific parameters and geometric relations. Next, a DOF simulation of a basic combination unit composed of three 3 UU-3 URU units is performed. Finally, a prototype of the basic combination unit is manufactured, and the DOF of the mechanism is experimentally verified.

关键词： Basic combination unit Degree of freedom(DOF) Deployable truss antenna Simulation analysis Structural design

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Corrigendum to “Research on the influence of differential speed ratio on the microstructure and properties of 316L/Ni/EH40 composite plate by asymmetrical rolling” [Mater. Today Commun. 37 (2023) 107431]

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Materials Today Communications 2024年 38卷

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

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