The Experts below are selected from a list of 270 Experts worldwide ranked by ideXlab platform

Xiulong Chen - One of the best experts on this subject based on the ideXlab platform.

  • Effects of Spherical Clearance Joint on Dynamics of Redundant Driving Spatial Parallel Mechanism
    Robotica, 2020
    Co-Authors: Xiulong Chen, Jingyao Guo
    Abstract:

    SUMMARY This paper proposes a dynamic modeling method of redundant drive Spatial Parallel Mechanism, dynamics of 4-UPS-RPU redundant driving Spatial Parallel Mechanism considering spherical joint clearance are analyzed. The dynamic equation of spherical joint clearance with Lagrange multiplier is built. The influences of single clearance and multiple clearances on dynamic responses of redundant drive Spatial Parallel Mechanisms are analyzed under different clearance values. The results show that the dynamic characteristics of the Mechanism with single clearance are basically consistent with the ideal situation, and the dynamic characteristics of the Mechanism with multi-clearance are significantly different from the ideal situation.

  • Dynamics Analysis of Spatial Parallel Mechanism with Irregular Spherical Joint Clearance
    Shock and Vibration, 2019
    Co-Authors: Xiulong Chen
    Abstract:

    Clearances caused by machining accuracy and assembly requirements are regular, but they will be irregular due to the wear of the kinematic pairs. At present, there are few studies on wear of space kinematic pairs. In order to grasp the effect of irregular spherical joint clearance after wear on the dynamic response, a method for solving irregular clearance problems based on the Newton–Euler method is proposed, and the dynamic response of 4-UPS-UPU Spatial Parallel Mechanism with irregular spherical joint clearance is investigated. The kinematic model and contact force model of the clearance of the spherical joint are derived. The dynamic model of the Mechanism with spherical joint clearance is established by the Newton–Euler method. Based on the Archard model, the three-dimensional dynamic wear model for spherical joint with clearances is developed. The wear depth and wear position of the spherical joint are obtained by the numerical solution. The method of reconstructing the geometric morphology after wear is proposed based on the finite element thought. The solution of the irregular clearance problem is put forward, and the dynamic response of the Mechanism after wear is also analyzed. The results show that the dynamic response curves of the Mechanism fluctuate around the ideal curves whether before wear or after wear. Compared with the regular clearance before wear, the results of the irregular clearance after wear have a greater impact on acceleration and contact force, and the vibration of the acceleration and contact force curve become more intense than before. Moreover, the displacement, velocity, and acceleration curves of the irregular clearance show some hysteresis than that before wear. Therefore, it can be inferred that the irregular clearance has more adverse effects on the Mechanism and aggravates the wear between the elements of the kinematic joint; in addition, the stability and the reliability of the Mechanism can be reduced.

  • Dynamic modeling of Spatial Parallel Mechanism with multi-spherical joint clearances:
    International Journal of Advanced Robotic Systems, 2019
    Co-Authors: Xiulong Chen, Chenghao Sun
    Abstract:

    The Parallel Mechanism has advantages of the high speed, high precision, strong carrying capacity, and high structural rigidity. Most of the previous studies concerning the dynamic modeling focused...

  • Chaotic characteristic analysis of Spatial Parallel Mechanism with clearance in spherical joint
    Nonlinear Dynamics, 2018
    Co-Authors: Xiulong Chen, Yu Deng, Wenhua Gao, Qing Wang
    Abstract:

    The spherical joint is one of the main motion pairs in Spatial Parallel Mechanism, and the spherical clearance has a great effect on the nonlinear dynamic performance of Parallel Mechanism. Most previous studies mainly focused on planar Mechanism with revolute joint, Spatial Parallel Mechanism with spherical clearance researched rarely. In this paper, the chaotic characteristic analysis of Spatial 4-UPS (universal joint-prismatic pair-spherical joint)-RPU (revolute joint-prismatic pair-universal joint) Parallel Mechanism with spherical clearance is investigated. The models of spherical joint with clearance are established, and then the nonlinear dynamics equation of the Parallel Mechanism with spherical clearance is derived by Lagrange method. The influence of clearance on displacement, velocity and acceleration of moving platform is both analyzed. And the influence of different clearance sizes on contact force and center trajectory of the spherical clearance is analyzed, and the chaotic characteristics of spherical joint and the Mechanism are all studied by phase diagram, Poincare section mapping method and Lyapunov exponent. The results show that spherical clearance has great influence on the nonlinear dynamic performance of 4-UPS-RPU Parallel Mechanism, and chaos exists in the dynamic response of spherical clearance and the Mechanism. As the clearance value increases, the stability of the Mechanism is weakened. When the clearance value increases to 2.1 mm, chaotic motion appeared on the moving platform of the Mechanism. This research is a useful attempt to study the nonlinear dynamics characteristic of Parallel Mechanisms with spherical clearance, which has guiding significance and practical value for further research on the design and chaotic control of Parallel Mechanism.

  • Bifurcation and chaotic behaviors of 4-UPS-RPS high-speed Parallel Mechanism
    Journal of Vibroengineering, 2018
    Co-Authors: Xiulong Chen, Yonghao Jia
    Abstract:

    In order to grasp the nonlinear characteristics of high-speed Spatial Parallel Mechanism, the bifurcation and chaotic behaviors of 4-UPS-RPS Mechanism are analyzed. Firstly, the nonlinear elastic dynamic model of the Mechanism is established by using the Lagrange equation and the finite element method. Then the effects of parameters including driving angular velocity, the radius of motion trajectory, the material of driving limbs, the diameter of driving limbs, and the mass of moving platform, on the bifurcation and chaotic behaviors of high-speed Spatial Parallel Mechanism are studied. The results show that the above parameters all have a certain influence on nonlinear characteristics of the 4-UPS-RPS high-speed Spatial Parallel Mechanism. The research can provide important theoretical basis for the further research on the non-linear dynamics of Spatial Parallel Mechanism.

Yuan Zhang - One of the best experts on this subject based on the ideXlab platform.

  • Workspace Analysis of 2-RPU & 2-SPS Spatial Parallel Mechanism
    2020 IEEE International Conference on Mechatronics and Automation (ICMA), 2020
    Co-Authors: Xuehao Meng, Yuan Zhang
    Abstract:

    In this paper, the workspace of a new type of Spatial Parallel Mechanism (SPM) is studied, namely 2-RPU& 2- SPS. Firstly, the model and components of Parallel Mechanism are introduced, and the degree of freedom (DOF) is calculated. Secondly, the inverse kinematic solution equation of the Mechanism was established, the constraint conditions of the components were analyzed. Finally, the workspace of the Mechanism was solved by MATLAB software, and the position and posture workspace of the Mechanism was obtained, and the method of approximate calculating the area of the position workspace by using “point set”. The results provide a theoretical basis for the further study of this kind of low degree of freedom Parallel Mechanism.

  • workspace analysis of 2 rpu 2 sps Spatial Parallel Mechanism
    International Conference on Mechatronics and Automation, 2020
    Co-Authors: Xuehao Meng, Yuan Zhang
    Abstract:

    In this paper, the workspace of a new type of Spatial Parallel Mechanism (SPM) is studied, namely 2-RPU& 2- SPS. Firstly, the model and components of Parallel Mechanism are introduced, and the degree of freedom (DOF) is calculated. Secondly, the inverse kinematic solution equation of the Mechanism was established, the constraint conditions of the components were analyzed. Finally, the workspace of the Mechanism was solved by MATLAB software, and the position and posture workspace of the Mechanism was obtained, and the method of approximate calculating the area of the position workspace by using “point set”. The results provide a theoretical basis for the further study of this kind of low degree of freedom Parallel Mechanism.

Qing Wang - One of the best experts on this subject based on the ideXlab platform.

  • Chaotic characteristic analysis of Spatial Parallel Mechanism with clearance in spherical joint
    Nonlinear Dynamics, 2018
    Co-Authors: Xiulong Chen, Yu Deng, Wenhua Gao, Qing Wang
    Abstract:

    The spherical joint is one of the main motion pairs in Spatial Parallel Mechanism, and the spherical clearance has a great effect on the nonlinear dynamic performance of Parallel Mechanism. Most previous studies mainly focused on planar Mechanism with revolute joint, Spatial Parallel Mechanism with spherical clearance researched rarely. In this paper, the chaotic characteristic analysis of Spatial 4-UPS (universal joint-prismatic pair-spherical joint)-RPU (revolute joint-prismatic pair-universal joint) Parallel Mechanism with spherical clearance is investigated. The models of spherical joint with clearance are established, and then the nonlinear dynamics equation of the Parallel Mechanism with spherical clearance is derived by Lagrange method. The influence of clearance on displacement, velocity and acceleration of moving platform is both analyzed. And the influence of different clearance sizes on contact force and center trajectory of the spherical clearance is analyzed, and the chaotic characteristics of spherical joint and the Mechanism are all studied by phase diagram, Poincare section mapping method and Lyapunov exponent. The results show that spherical clearance has great influence on the nonlinear dynamic performance of 4-UPS-RPU Parallel Mechanism, and chaos exists in the dynamic response of spherical clearance and the Mechanism. As the clearance value increases, the stability of the Mechanism is weakened. When the clearance value increases to 2.1 mm, chaotic motion appeared on the moving platform of the Mechanism. This research is a useful attempt to study the nonlinear dynamics characteristic of Parallel Mechanisms with spherical clearance, which has guiding significance and practical value for further research on the design and chaotic control of Parallel Mechanism.

  • Dynamic response analysis and chaos identification of 4-UPS-UPU flexible Spatial Parallel Mechanism
    Nonlinear Dynamics, 2017
    Co-Authors: Xiulong Chen, Liangkai Wu, Yu Deng, Qing Wang
    Abstract:

    In order to realize the dynamic response analysis and the chaos identification of flexible Spatial Parallel Mechanism, the nonlinear elastic dynamics model of 4-UPS-UPU flexible Parallel Mechanism is established under the ideal situation, and the dynamic response, phase diagrams, Poincare map and largest Lyapunov exponent of the Spatial Parallel Mechanism are investigated. Based on the finite element method, the driving limbs of Spatial Parallel Mechanism are divided into elements. The kinetic energy equation and potential energy equation of units are built. Then the nonlinear elastic dynamics model of 4-UPS-UPU Parallel Mechanism is acquired by Lagrange equation. The dynamic response of kinematic error for 4-UPS-UPU flexible Parallel Mechanism is analyzed. In addition, the chaos phenomenon contained in the Mechanism is identified by phase diagrams, Poincare map and largest Lyapunov exponent, respectively. Subsequently, the relationship between the basic parameters of Parallel Mechanism and largest Lyapunov exponent is discussed. The results indicate that there exists chaotic phenomena in the 4-UPS-UPU flexible Parallel Mechanism, and the basic parameters, including the material of driving limbs, diameter of driving limbs, mass of moving platform and the distribution radius of hinges of moving platform all have great effect on chaotic motion of 4-UPS-UPU flexible Parallel Mechanism. The researches can provide important theoretical for the further nonlinear dynamics behaviors research and optimal design of 4-UPS-UPU flexible Spatial Parallel Mechanism.

  • Nonlinear characteristic analysis of high-speed Spatial Parallel Mechanism
    Journal of Vibroengineering, 2015
    Co-Authors: Xiulong Chen, Yu Deng, Xiaoxia Liang, Qing Wang
    Abstract:

    In order to grasp the nonlinear characteristic of high-speed Spatial Parallel Mechanism, the analysis of nonlinear characteristics for Spatial Parallel Mechanism is investigated. The nonlinear elastic dynamic equation of 4-UPS-UPU high-speed Spatial Parallel Mechanism is derived by kineto-elastodynamics theory, the dynamic equation is solved by numerical method, the nonlinear characteristic of the Parallel Mechanism is analyzed by phase diagram. Numerical results show that 4-UPS-UPU high-speed Spatial Parallel Mechanism exhibits typical nonlinear characteristic during exercise, the factors, such as the motion trajectory of Parallel Mechanism, the material of driving limbs, the diameter of driving limbs and the mass of moving platform, are also have effect on nonlinear characteristics of Parallel Mechanism. Therefore the reasonable choice of the above factors can weaken the chaos motion. This researches provide important theoretical base of the chaos suppression for Spatial Parallel Mechanism.

  • Rigid Dynamic Model and Analysis of 5-DOF Parallel Mechanism
    International Journal of Advanced Robotic Systems, 2015
    Co-Authors: Xiulong Chen, Yu Deng, Xiaoxia Liang, Qing Wang
    Abstract:

    This paper introduces a novel 4-UPS-RPS Spatial Parallel Mechanism, which can achieve three rotation degrees and two translation degrees of freedom. A rigid dynamic model is established and analysis of the Parallel Mechanism is carried out. The kinematics of the RPS and UPS driving limbs are analysed and the velocity-mapping relationships between the driving limbs and the other parts are built. The load conditions of the parts are analysed, and the rigid dynamic model of the 4-UPS-RPS Parallel Mechanism is derived by the virtual work principle approach. Using the example of the Parallel Mechanism movement, a driving forces analysis of the 4-UPS-RPS Parallel Mechanism is carried out, and the correctness of the rigid dynamic model is verified by numerical calculation and virtual simulation.

Xuehao Meng - One of the best experts on this subject based on the ideXlab platform.

  • Workspace Analysis of 2-RPU & 2-SPS Spatial Parallel Mechanism
    2020 IEEE International Conference on Mechatronics and Automation (ICMA), 2020
    Co-Authors: Xuehao Meng, Yuan Zhang
    Abstract:

    In this paper, the workspace of a new type of Spatial Parallel Mechanism (SPM) is studied, namely 2-RPU& 2- SPS. Firstly, the model and components of Parallel Mechanism are introduced, and the degree of freedom (DOF) is calculated. Secondly, the inverse kinematic solution equation of the Mechanism was established, the constraint conditions of the components were analyzed. Finally, the workspace of the Mechanism was solved by MATLAB software, and the position and posture workspace of the Mechanism was obtained, and the method of approximate calculating the area of the position workspace by using “point set”. The results provide a theoretical basis for the further study of this kind of low degree of freedom Parallel Mechanism.

  • workspace analysis of 2 rpu 2 sps Spatial Parallel Mechanism
    International Conference on Mechatronics and Automation, 2020
    Co-Authors: Xuehao Meng, Yuan Zhang
    Abstract:

    In this paper, the workspace of a new type of Spatial Parallel Mechanism (SPM) is studied, namely 2-RPU& 2- SPS. Firstly, the model and components of Parallel Mechanism are introduced, and the degree of freedom (DOF) is calculated. Secondly, the inverse kinematic solution equation of the Mechanism was established, the constraint conditions of the components were analyzed. Finally, the workspace of the Mechanism was solved by MATLAB software, and the position and posture workspace of the Mechanism was obtained, and the method of approximate calculating the area of the position workspace by using “point set”. The results provide a theoretical basis for the further study of this kind of low degree of freedom Parallel Mechanism.

Jia Yonghao - One of the best experts on this subject based on the ideXlab platform.

  • Wear Analysis of Spatial Parallel Mechanisms With Multiple Three-Dimensional Spherical Clearance Joints
    Journal of Tribology, 2019
    Co-Authors: Chen Xiulong, Jia Yonghao
    Abstract:

    The goal of this work is to investigate the dynamic responses of the Parallel Mechanism with irregular clearances caused by wear and to further reveal the influences of multiple clearance interaction on wear. The motion model and the force model of spherical clearance joint based on a continuous contact force model and a static friction model are established. The dynamic equation of the Spatial Parallel Mechanism considering two spherical clearance joints is derived. A general wear analysis strategy to establish spherical clearance joint with sustainable updation of the surface profile is presented, and the dynamic responses of Parallel Mechanism after wear are studied. The interaction between two wear joints with different initial clearance values is further investigated. The results show that it is necessary to consider the factor of irregular clearances caused by wear in the analysis of dynamics behavior for precision Mechanisms. Proper distribution of clearance values can reduce wear of clearance joint and improve the useful life of Mechanism to a certain extent. This work provides a foundation for life prediction and reliability analysis of Parallel Mechanisms.

  • Dynamic Response and Nonlinear Characteristics of Spatial Parallel Mechanism With Spherical Clearance Joint
    Journal of Computational and Nonlinear Dynamics, 2019
    Co-Authors: Chen Xiulong, Li Yuewen, Jia Yonghao
    Abstract:

    Spherical joint is a type of common kinematic pair in Spatial Parallel Mechanism. The existence of spherical joint clearance has many adverse effects on the Mechanism. A method of forecasting the dynamic behaviors of Spatial Parallel Mechanism with spherical clearance joint is proposed. The 4-UPS-UPU Spatial Parallel Mechanism with spherical clearance is taken as the research object, the dynamic response, and nonlinear characteristics of the Mechanism are studied. The kinematic model and the contact force model of the spherical clearance are established. The dynamic equation of the Spatial Parallel Mechanism with spherical joint clearance is derived by Newton–Euler method. The above-mentioned dynamic equation is solved by using the ODE113 function that is based on a variable order numerical differential algorithm in matlab. The dynamic responses of moving platform with different clearance values are analyzed. The contact force and the center trajectory of the sphere at the spherical joint are obtained. In addition, the phase trajectory, Poincare map, and bifurcation diagram are analyzed, and the nonlinear characteristics of the spherical clearance joint and the moving platform are obtained. By comparing the results, such as the acceleration of moving platform and the contact force, with virtual prototype simulation, the correctness of the dynamic equation of the Spatial Parallel Mechanism with spherical clearance joint and the analysis results are verified. The researches show that the change of clearance value has a great influence on the motion state of spherical clearance joint, and chaos phenomena appears in the clearance joint with the increase in the clearance value. And the impact phenomenon appears between the spherical joint elements, which makes the Mechanism generated vibration.

  • Dynamics Behavior Analysis of Parallel Mechanism with Joint Clearance and Flexible Links
    Shock and Vibration, 2018
    Co-Authors: Chen Xiulong, Jia Yonghao, Wang Qing
    Abstract:

    In this study, the dynamics behaviors analysis of Parallel Mechanism considering joint clearance and flexible links are investigated using a computational methodology. The nonlinear dynamic model of 4-UPS-RPS Spatial Parallel Mechanism with clearance in spherical joint and flexible links is established by combining KED method and Lagrange method. The dynamic responses including collision force and motion characteristics of the moving platform are obtained. Chaos and bifurcation are analyzed. The effects of different clearances on the dynamics behaviors of the Parallel Mechanism are studied. The results show that 4-UPS-RPS Spatial Parallel Mechanism is very sensitive to joint clearance and flexible links, and small variations in the clearance value can cause the Mechanism change from periodic motion to chaotic motion. This research provides a methodology for forecasting the dynamics behavior of Parallel Mechanisms with clearance and flexible links.