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An energy efficiency evaluation method for parallel robots based on the kinetic energy change rate

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Science China(Technological Sciences) 2019年第6期62卷 1035-1044页

作者： LIU XinJun BI WeiYao xie fugui The State Key Laboratory of Tribology & Tsinghua University (DME)-Siemens Joint Research Center for Advanced Robotics Department of Mechanical Engineering (DME) Tsinghua University Beijing 100084 China Beijing Key Lab of Precision/Ultra-precision Manufacturing Equipments and Control Tsinghua University Beijing 100084 China

Benefit from the high payload-to-weight ratio, parallel robots are expected to have a high potential for energy savings. However,it is a challenging issue to evaluate the energy efficiency of parallel robots with a quantitative method. Quantitative energy efficiency evaluation methods include energy efficiency evaluation models and indices which mathematically describe the relationship between energy consumers in models and design variables of robots, such as geometry, mass and inertia *** the structural features of parallel robots, the chains and the end effectors are identified as two separated energy consumers. Besides, the chains in parallel robots are identified as a transmission system which transfers energy from drives to the end effectors. On this basis, an energy efficiency evaluation model considering the change rate of kinetic energy stored in chains is built. The kinetic energy change rate of chains is influenced by design variables of robots as well as motion of the end *** order to give a quantitative description of energy efficiency performance of parallel robots, indices considering arbitrary velocity vector of the end effector are proposed. The evaluation method is suitable for all kinds of parallel robots with various motion conditions. Furthermore, the method can be used to optimize machining parameters and guide the design of energyefficient machines.

关键词： energy efficiency evaluation parallel robots kinetic energy power transmission

Optimal Design of a Main Driving Mechanism for Servo Punch Press Based on Performance Atlases

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Chinese Journal of Mechanical Engineering 2013年第5期26卷 909-917页

作者： ZHOU Yanhua xie fugui LIU Xinjun Department of Precision Instruments and Mechanology Tsinghua University Institute of Aircraft Engineering Naval Aeronautical and Astronautical University Beijing Key Lab of Precision/Ultra-precision Manufacturing Equipments and Control Tsinghua University

The servomotor drive turret punch press is attracting more attentions and being developed more intensively due to the advantages of high speed,high accuracy,high flexibility,high productivity,low noise,cleaning and energy *** effectively improve the performance and lower the cost,it is necessary to develop new mechanisms and establish corresponding optimal design method with uniform performance indices.A new patented main driving mechanism and a new optimal design method are *** the optimal design,the performance indices,i.e.,the local motion/force transmission indices ITI,OTI,good transmission workspace good transmission workspace(GTW) and the global transmission indices GTIs are *** non-dimensional normalization method is used to get all feasible solutions in dimensional ***,the performance atlases,which can present all possible design solutions,are *** a result,the feasible solution of the mechanism with good motion/force transmission performance is *** the solution can be flexibly adjusted by designer according to the practical design *** proposed mechanism is original,and the presented design method provides a feasible solution to the optimal design of the main driving mechanism for servo punch press.

关键词： servo punch press main driving mechanism dimensional optimization transmission index performance atlas

Type Synthesis of 4-DOF Parallel Kinematic Mechanisms Based on Grassmann Line Geometry and Atlas Method

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Chinese Journal of Mechanical Engineering 2013年第6期26卷 1073-1081页

作者： xie fugui LI Tiemin LIU Xinjun Department of Mechanical Engineering Tsinghua University Department of Precision Instruments Tsinghua University Beijing Key Lab of Precision/Ultra-precision Manufacturing Equipments and Control Tsinghua University

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 of 4-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.

关键词： type synthesis parallel kinematic mechanism Grassmann line geometry atlas method

Analysis of the kinematic characteristics of a high-speed parallel robot with Sch6nflies motion： Mobility, kinematics, and singularity

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Frontiers of Mechanical Engineering 2016年第2期11卷 135-143页

作者： fugui xie Xin-Jun LIU The State Key Laboratory of Tribology & Institute of Manufacturing Engineering Department of Mechanical Engineering Tsinghua Uni- versity Beijing 100084 China Beijing Key Laboratory of Precision/ Ultra-precision Manufacturing Equipment and Control Tsinghua University Beijing 100084 China

This study introduces a high-speed parallel robot with Schonflies motion. This robot exhibits a promising prospect in realizing high-speed pick-and- place manipulation for packaging production lines. The robot has four identical limbs and a single platform. Its compact structure and single-platform concept provides this robot with good dynamic response potential. A line graph method based on Grassmann line geometry is used to investigate the mobility characteristics of the proposed robot. A generalized Blanding rule is also introduced into this procedure to realize mutual conversion between the line graphs for motions and constraints. Subsequently, the inverse kinematics is derived, and the singularity issue of the robot is investigated using both qualitative and quantitative approaches. Input and output transmission singularity indices are defined based on the reciprocal product in screw theory and the virtual coefficient by considering motion/force transmission performance. Thereafter, the singular loci of the proposed robot with specific geometric parameters are derived. The mobility analysis, inverse kinematics modeling, and singularity analysis conducted in this study are helpful in developing the robot.

关键词： parallel robot mobility inverse kinematics,singularity transmission performance

Robotic mobile and mirror milling of large-scale complex structures

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National Science Review 2023年第5期10卷 10-13页

作者： Zenghui xie fugui xie Limin Zhu Xin-Jun Liu State Key Laboratory of Tribology in Advanced Equipment Department of Mechanical Engineering(DME) Tsinghua University Beijing Key Lab of Precision/Ultra-precision Manufacturing Equipments and Control Tsinghua University State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong University

Large-scale complex structures,such as spacecraft cabins,aircraft composite skins and launch vehicle fuel tanks,are the core components of the equipment in aerospace,energy,shipbuilding and other *** milling quality and efficiency are factors directly affecting the performance and productivity of spacecraft,aircraft and other key *** kind of structure generally features large dimension,high accuracy,

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Evolution and Development Trend Prospect of Metal Milling Equipment

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Chinese Journal of Mechanical Engineering 2023年第2期36卷 1-15页

作者： Jie Wen fugui xie Xinjun Liu Yi Yue Department of Mechanical Engineering(DME) Tsinghua UniversityBeijing 100084China Beijing Key Lab of Precision/Ultra‑Precision Manufacturing Equipments and Control Tsinghua UniversityBeijing 100084China Beijing Spacecrafts Beijing 100094China

The world is currently undergoing profound changes which have never happened within the past *** competition in the technology and industry fields is becoming increasingly *** strategic competition of the major powers further focuses on the manufacturing *** countries such as the United States,Germany,and Japan have successively put forward strategic plans such as“re-industrialization”and“return of manufacturing industry”,aiming to seize the commanding heights of a new round of global high-end technology competition and expand international market *** at the historic intersection of a new round of scientific and technological revolution and China's accelerated high-quality development,the“14th Five-Year Plan”clearly pointed out that intelligent manufacturing is the main development trend to promote China's manufacturing to the medium-high end of the global value *** reflects the importance of advanced manufacturing for national strategic *** better grasp the development direction of advanced manufacturing equipment,the development process and current application status of manufacturing equipment are summarized,and thereafter the characteristics of manufacturing equipment in different development stages of the manufacturing industry are ***,the development trend of advanced milling equipment is prospected.

关键词： Intelligent manufacturing High-quality development Milling equipment Evolution and development trend

Error Modeling and Sensitivity Analysis of a Parallel Robot with SCARA(Selective Compliance Assembly Robot Arm) Motions

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Chinese Journal of Mechanical Engineering 2014年第4期27卷 693-702页

作者： CHEN Yuzhen xie fugui LIU Xinjun ZHOU Yanhua Department of Mechanical Engineering Tsinghua University Beijing Key Lab of Precision/Ultra-precision Manufacturing Equipments and Control Tsinghua University Institute of Aircraft Engineering Naval Aeronautical and Astronautical University

Parallel robots with SCARA（selective compliance assembly robot arm） motions are utilized widely in the field of high speed pick-and-place manipulation. Error modeling for these robots generally simplifies the parallelogram structures included by the robots as a link. As the established error model fails to reflect the error feature of the parallelogram structures, the effect of accuracy design and kinematic calibration based on the error model come to be undermined. An error modeling methodology is proposed to establish an error model of parallel robots with parallelogram structures. The error model can embody the geometric errors of all joints, including the joints of parallelogram structures. Thus it can contain more exhaustively the factors that reduce the accuracy of the robot. Based on the error model and some sensitivity indices defined in the sense of statistics, sensitivity analysis is carried out. Accordingly, some atlases are depicted to express each geometric error’s influence on the moving platform’s pose errors. From these atlases, the geometric errors that have greater impact on the accuracy of the moving platform are identified, and some sensitive areas where the pose errors of the moving platform are extremely sensitive to the geometric errors are also figured out. By taking into account the error factors which are generally neglected in all existing modeling methods, the proposed modeling method can thoroughly disclose the process of error transmission and enhance the efficacy of accuracy design and calibration.

关键词： parallel robot selective compliance assembly robot arm(SCARA) motions error modeling sensitivity analysis parallelogram structure

Evaluation of the power consumption of a high-speed parallel robot

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Frontiers of Mechanical Engineering 2018年第2期13卷 167-178页

作者： Gang HAN fugui xie Xin-Jun LIU The State Key Laboratory of Tribology & Institute of Manufacturing Engineering Department of Mechanical Engineering Tsinghua University Beijing 100084 China Beijing Key Laboratory of Precision/Ultra-precision Manufacturing Equipments and Control Tsinghua University Beijing 100084 China

An inverse dynamic model of a high-speed parallel robot is established based on the virtual work principle. With this dynamic model, a new evaluation method is proposed to measure the power consumption of the robot during pick-and-place tasks. The power vector is extended in this method and used to represent the collinear velocity and acceleration of the moving platform. After- ward, several dynamic performance indices, which are homogenous and possess obvious physical meanings, are proposed. These indices can evaluate the power input and output transmissibility of the robot in a workspace. The distributions of the power input and output transmissibility of the high-speed parallel robot are derived with these indices and clearly illustrated in atlases. Furtherly, a low- power-consumption workspace is selected for the robot.

关键词： high-speed parallel robot dynamic model power consumption evaluation method power vector

Conceptual design and kinematic analysis of a novel parallel robot for high-speed pick-and-place operations

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Frontiers of Mechanical Engineering 2018年第2期13卷 211-224页

作者： Qizhi MENG fugui xie Xin-Jun LIU The State Key Laboratory of Tribology & Institute of Manufacturing Engineering Department of Mechanical Engineering Tsinghua University Beijing 100084 China Beijing Key Laboratory of Precision/Ultra-precision Manufacturing Equipments and Control Tsinghua University Beijing 100084 China

This paper deals with the conceptual design, kinematic analysis and workspace identification of a novel four degrees-of-freedom （DOFs） high-speed spatial parallel robot for pick-and-place operations. The proposed spatial parallel robot consists of a base, four arms and a 11/2 mobile platform. The mobile platform is a major innova- tion that avoids output singularity and offers the advantages of both single and double platforms. To investigate the characteristics of the robot＇s DOFs, a line graph method based on Grassmann line geometry is adopted in mobility analysis. In addition, the inverse kinematics is derived, and the constraint conditions to identify the correct solution are also provided. On the basis of the proposed concept, the workspace of the robot is identified using a set of presupposed parameters by taking input and output transmission index as the performance evaluation criteria.

关键词： spatial parallel robot pick-and-place operations mobility analysis kinematic modeling workspace identification