Dynamic Analysis of 4-SPS/CU Parallel Mechanism Considering Three-Dimensional Wear of Spherical Joint With Clearance

2017 ◽  
Vol 139 (2) ◽  
Author(s):  
Gengxiang Wang ◽  
Hongzhao Liu ◽  
Peisheng Deng ◽  
Kaiming Yin ◽  
Guanggang Zhang
Keyword(s):  
Contact Force ◽  
Parallel Mechanism ◽  
Three Dimensional ◽  
Force Model ◽  
Wear Depth ◽  
Wear Property ◽  
Spherical Joint ◽  
Wear Model ◽  
Contact Force Model ◽  
Three Components

The dynamic performance of 4-SPS/CU (spherical joint, prismatic joint, cylindrical joint, and universal joint) parallel mechanism considering spherical joint with clearance is developed, and the three-dimensional (3D) wear property of the socket is based on the Archard's wear model. First, the kinematics model of spherical joint with clearance is established, and the updated procedure pertaining to the contact mechanics and wear state is explained via a flowchart. An improved contact force model was proposed by Flores et al. contact force model through a revised contact stiffness coefficient. The normal and tangential contact forces between ball and socket are calculated using the improved contact force model and a modified Coulomb friction model. Second, the dynamic model of the parallel mechanism considering spherical joint with clearance is formulated based on the multibody equations of motion. In order to obtain the 3D wear property of spherical joint with clearance, the contact force is decomposed into three components in the global coordinate system. The three components of sliding distance are computed based on the 3D revolute property of the parallel mechanism. Finally, the contact pressures in three different directions are calculated by the corresponding contact force and approximate contact area components for the sake of predicting the 3D wear depth of socket based on the Archard's wear model. The simulation results show that the wear depth in different directions along the socket surface is nonuniform, which affects the performance of 4-SPS/CU parallel mechanism.

Dynamic Analysis and Wear Prediction of Planar Five-Bar Mechanism Considering Multiflexible Links and Multiclearance Joints

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Gengxiang Wang ◽  
Hongzhao Liu
Keyword(s):  
Contact Force ◽  
Dynamic Performance ◽  
Contact Forces ◽  
Force Model ◽  
Displacement Curve ◽  
Wear Depth ◽  
Wear Model ◽  
Clearance Joint ◽  
Contact Force Model ◽  
Cylindrical Joint

Effects of wear and member flexibility on the dynamic performance of a planar five-bar mechanism with joint-clearance are investigated. The equation of motion of the mechanism is derived based on the absolute nodal coordinate formulation (ANCF). In order to enhance the accuracy of the contact force, the slope of the load–displacement curve of the cylindrical joint with clearance is used. The contact deformation couples the joint wear to the contact state. The contact force model of Flores and coworkers is improved, by the introduction of the stiffness coefficient. The wear depth is predicted by using the Archard's wear model. Simulations show that the multiclearance joints can generate stronger contact forces relative to single clearance joint case. This leads to more severe wear in the joint. However, the mechanism with multiple flexible links can absorb more of the energy arising from the clearance joint, and this improves the wear phenomenon.

Dynamics Analysis of Spatial Multibody System With Spherical Joint Wear

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Gengxiang Wang ◽  
Hongzhao Liu ◽  
Peisheng Deng
Keyword(s):  
Contact Pressure ◽  
Contact Force ◽  
Contact Area ◽  
Multibody Systems ◽  
Multibody System ◽  
Equations Of Motion ◽  
Force Model ◽  
Spherical Joint ◽  
Wear Model ◽  
Contact Force Model

The influence of the spherical joint with clearance caused by wear on the dynamics performance of spatial multibody system is predicted based on the Archard's wear model and equations of motion of multibody systems. First, the function of contact deformation and load acting on the spherical joint with clearance is derived based on the improved Winkler elastic foundation model and Hertz quadratic pressure distribution assumption. On this basis, considering the influence of clearance size and wear state on the contact stiffness between spherical joint elements, an improved contact force model is proposed by Lankarani–Nikravesh contact force model and improved stiffness coefficient that is the slope of the function of contact deformation and load. Second, due to the complexity for that wear impacts on the surface topography of contact bodies, an approximate calculation method of contact area with respect to the clearance spherical joint is provided for simplifying the computational process of contact pressure in the Archard's wear model. Subsequently, the contact pressure between contact bodies is calculated by the improved contact force model and approximate contact area (ICFM–ACA), which is verified via finite element method (FEM). Moreover, the dynamics model of spatial four bar mechanism considering spherical joint with clearance caused by wear is formulated using equations of motion of multibody systems. Finally, the wear depth of spherical joint with clearance is predicted via two different kinds of contact pressure based on the Archard's wear model (one is from the ICFM–ACA and the other is from FEM), respectively. The numerical simulation results show that the improved contact force model and proposed approximate contact area are correctness and validity for predicting wear in the spherical joint with clearance. Simultaneously, the effect of the spherical joint with clearance caused by wear on the dynamics performance of spatial four bar mechanism is analyzed.

scholarly journals Dynamics Analysis of Spatial Parallel Mechanism with Irregular Spherical Joint Clearance

2019 ◽  
Vol 2019 ◽  
pp. 1-21
Author(s):  
Xiulong Chen ◽  
Yuewen Li
Keyword(s):  
Dynamic Response ◽  
Contact Force ◽  
Parallel Mechanism ◽  
Euler Method ◽  
Joint Clearance ◽  
Force Model ◽  
Wear Depth ◽  
Spherical Joint ◽  
Spatial Parallel Mechanism ◽  
Dynamic Wear

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.

Three-Dimensional Wear Prediction of Four-Degrees-of-Freedom Parallel Mechanism With Clearance Spherical Joint and Flexible Moving Platform

2018 ◽  
Vol 140 (3) ◽  
Author(s):  
Gengxiang Wang ◽  
Hongzhao Liu
Keyword(s):  
Contact Force ◽  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Contact Forces ◽  
Force Model ◽  
Spherical Joint ◽  
Normal Contact ◽  
Tangential Contact ◽  
Moving Platform

Three-dimensional (3D) wear of the clearance spherical joint in four-degrees-of-freedom (DOF) parallel mechanism is predicted based on Archard's wear model. The flexible moving platform is treated as thin plate element based on absolute nodal coordinate formulation (ANCF). The tangent frame is introduced to formulate the constraint equation of universal joint. One of the spherical joints is treated as clearance joint. The normal and tangential contact forces are calculated based on Flores contact force model and modified Coulomb friction model. In order to predict 3D wear, the normal contact force, tangential contact velocity, and eccentricity vector are decomposed in the global coordinate system. Simulation results show that 3D wear occurred in three directions are not uniform each other.

scholarly journals Dynamics of Multibody Systems With Spherical Clearance Joints

2005 ◽  
Author(s):  
P. Flores ◽  
J. Ambro´sio ◽  
J. C. P. Claro ◽  
H. M. Lankarani
Keyword(s):  
Contact Force ◽  
Multibody Systems ◽  
Contact Forces ◽  
Force Model ◽  
Clearance Joints ◽  
Continuous Contact ◽  
Clearance Joint ◽  
Contact Force Model ◽  
Dynamics Of Multibody Systems ◽  
The Impact

This work deals with a methodology to assess the influence of the spherical clearance joints in spatial multibody systems. The methodology is based on the Cartesian coordinates, being the dynamics of the joint elements modeled as impacting bodies and controlled by contact forces. The impacts and contacts are described by a continuous contact force model that accounts for geometric and mechanical characteristics of the contacting surfaces. The contact force is evaluated as function of the elastic pseudo-penetration between the impacting bodies, coupled with a nonlinear viscous-elastic factor representing the energy dissipation during the impact process. A spatial four bar mechanism is used as an illustrative example and some numerical results are presented, being the efficiency of the developed methodology discussed in the process of their presentation. The results obtained show that the inclusion of clearance joints in the modelization of spatial multibody systems significantly influences the prediction of components’ position and drastically increases the peaks in acceleration and reaction moments at the joints. Moreover, the system’s response clearly tends to be nonperiodic when a clearance joint is included in the simulation.

Hertz Contact Force Model With Permanent Indentation in Impact Analysis of Solids

1992 ◽  
Author(s):  
Hamid M. Lankarani ◽  
Parviz E. Nikravesh
Keyword(s):  
Contact Force ◽  
Impact Analysis ◽  
Equations Of Motion ◽  
Solid Particles ◽  
Hertzian Contact ◽  
Contact Period ◽  
Force Model ◽  
Unknown Parameters ◽  
Contact Force Model ◽  
Energy And Momentum

Abstract A continuous analysis method for the direct-central impact of two solid particles is presented. Based on the assumption that local plasticity effects are the sole factor accounting for the dissipation of energy in impact, a Hertzian contact force model with permanent indentation is constructed. Utilizing energy and momentum considerations, the unknown parameters in the model are analytically evaluated in terms of a given coefficient of restitution and velocities before impact. The equations of motion of the two solids may then be integrated forward in time knowing the variation of the contact force during the contact period. For Illustration, an impact of two soft metallic particles is studied.

Experimental Validation of a Volumetric Planetary Rover Wheel/Soil Interaction Model

2013 ◽  
Author(s):  
Willem Petersen ◽  
John McPhee
Keyword(s):  
Contact Force ◽  
Interaction Model ◽  
Contact Model ◽  
Soil Parameters ◽  
Model Parameters ◽  
Force Model ◽  
Normal Contact ◽  
Planetary Rover ◽  
Normal Contact Force ◽  
Contact Force Model

For the multibody simulation of planetary rover operations, a wheel-soil contact model is necessary to represent the forces and moments between the tire and the soft soil. A novel nonlinear contact modelling approach based on the properties of the hypervolume of interpenetration is validated in this paper. This normal contact force model is based on the Winkler foundation model with nonlinear spring properties. To fully define the proposed normal contact force model for this application, seven parameters are required. Besides the geometry parameters that can be easily measured, three soil parameters representing the hyperelastic and plastic properties of the soil have to be identified. Since it is very difficult to directly measure the latter set of soil parameters, they are identified by comparing computer simulations with experimental results of drawbar pull tests performed under different slip conditions on the Juno rover of the Canadian Space Agency (CSA). A multibody dynamics model of the Juno rover including the new wheel/soil interaction model was developed and simulated in MapleSim. To identify the wheel/soil contact model parameters, the cost function of the model residuals of the kinematic data is minimized. The volumetric contact model is then tested by using the identified contact model parameters in a forward dynamics simulation of the rover on an irregular 3-dimensional terrain and compared against experiments.

scholarly journals Chaos phenomenon and stability analysis of RU-RPR parallel mechanism with clearance and friction

2018 ◽  
Vol 10 (1) ◽  
pp. 168781401774625 ◽  
Author(s):  
Yulei Hou ◽  
Yi Wang ◽  
Guoning Jing ◽  
Yunjiao Deng ◽  
Daxing Zeng ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Contact Force ◽  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Force Model ◽  
Obvious Effect ◽  
Normal Contact ◽  
Rotational Degrees Of Freedom ◽  
The Stability ◽  
Baumgarte Stabilization

The chaos phenomenon often exists in the dynamics system of the mechanism with clearance and friction, which has obvious effect on the stability of the mechanism, then it is worthy of attention for identifying the relationship between the friction coefficient and the stability of the mechanism. Two rotational degrees of freedom decoupled parallel mechanism RU-RPR is taken as the research object. Considering the clearance existing in the revolute pair, Lankarani–Nikravesh contact force model is used to calculate the normal contact force, and the Coulomb friction force model is used to calculate the tangential contact force. The dynamics model is established using Newton–Euler equations, and the Baumgarte stabilization method is used to keep the stability of the numerical analysis. Then, the equations are solved using the fourth adaptive Runge–Kutta method, and the effect of the revolute pair’s clearance on the dynamic behavior is analyzed. Poincare mapping is plotted, and the bifurcation diagrams are analyzed with varying the friction coefficient corresponding to different values of clearance size. The research contents possess a certain theoretical guidance significance and practical application value on the analysis of the chaotic motion and its stability in the dynamics of the parallel mechanism.

A continuous contact force model for impact analysis

2022 ◽  
Vol 168 ◽  
pp. 108739
Author(s):  
Jie Zhang ◽  
Xu Liang ◽  
Zhonghai Zhang ◽  
Guanhua Feng ◽  
Quanliang Zhao ◽  
...  
Keyword(s):  
Contact Force ◽  
Impact Analysis ◽  
Force Model ◽  
Continuous Contact ◽  
Contact Force Model
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