Dynamic Characteristic Research of Planar Four-Bar Mechanism with Joint Clearance

2012 ◽  
Vol 215-216 ◽  
pp. 912-916 ◽  
Author(s):  
Shao Jun Bo ◽  
Rui Bin Guo
Keyword(s):  
Mechanism Design ◽  
Mechanical System ◽  
Dynamic Characteristic ◽  
Contact Force ◽  
Dynamic Characteristics ◽  
Geometrical Model ◽  
Accurate Prediction ◽  
Dynamics Simulation ◽  
Joint Clearance ◽  
Dynamics Analysis

The joint clearance on mechanism dynamic characteristics influence can not be ignored. This paper established a geometrical model of planar four-bar mechanism, it built the model of contact force and friction and embedded into the software of ADAMS dynamics analysis mechanical system, which analysis the dynamics simulation of mechanism. We obtain a accurate prediction of dynamic characteristics of mechanism with joint clearance effect from the analysis. What's more the results provide reference and basis for later mechanism design [1,2,3].

A DOE- and Kriging-Based Model for Studying on the Dynamics of Multibody Mechanical Systems With Revolute Joint Clearance

2013 ◽  
Author(s):  
Zhenhua Zhang ◽  
Liang Xu ◽  
Paulo Flores ◽  
Hamid M. Lankarani
Keyword(s):  
Simulation Model ◽  
Mechanical System ◽  
Contact Force ◽  
Design Parameter ◽  
Joint Clearance ◽  
Design Parameters ◽  
Force Model ◽  
Revolute Joint ◽  
Clearance Joint ◽  
Contact Force Model

Over the last two decades, extensive work has been conducted on dynamic effect of joint clearances in multibody mechanical systems. In contrast, little work has been devoted to optimizing the performance of these systems. In this study, analysis of revolute joint clearance is formulated in term of a Hertzian-based contact force model. For illustration, the classical slider-crank mechanism with a revolute clearance joint at the piston pin is presented, and a simulation model is developed using the analysis/design code MSC.ADAMS. The clearance is modeled as a pin-in-a-hole surface-to-surface dry contact, with appropriate contact force model between the joint and bearing surfaces. Different simulations are performed to demonstrate the influence of the joint clearance size and the input crank speed on the dynamic behavior of the system with the clearance joint. An innovative design-of-experiment (DOE)-based method for optimizing the performance of a mechanical system with the revolute joint clearance for different ranges of design parameters is then proposed. Based on the simulation model results from sample points, which are selected by a Latin hypercube sampling (LHS) method, a polynomial function Kriging meta-model is established instead of the actual simulation model. The reason for development and use of the meta-model is to bypass computationally intensive simulations of a computer model for different design parameter values in place of a more efficient and cost-effective mathematical model. Finally, numerical results obtained from two application examples, considering the different design parameters, including the joint clearance size, crank speed, and contact stiffness, are presented for further analyzing the dynamics of the revolute clearance joint in a mechanical system. This allows for predicting the influence of design parameter changes, in order to minimize contact forces, accelerations, and power requirements due to the existence of joint clearance.

The Dynamic Simulation of Contact Force between Wheels and Ground Based on ADAMS

2012 ◽  
Vol 510 ◽  
pp. 437-441 ◽  
Author(s):  
Zhi Sen Li ◽  
Hai Tao Wu ◽  
Hong Bin Liu
Keyword(s):  
Dynamic Simulation ◽  
Contact Force ◽  
Practical Problem ◽  
Great Influence ◽  
Dynamics Simulation ◽  
Dynamics Analysis ◽  
Main Research ◽  
Wheel Chair

Contact force is a complicated force in practical problem. By using the powerful function of ADAMS in dynamics analysis, we can solve it in a comparatively accurate way. Since a number of parameters are involved in the simulation in ADAMS, the initialization of them has a great influence on the simulation. Aiming at the contact force between wheels of wheel chair and ground, the value of the parameters was calculated and analyzed in this paper. The main research object in this paper is the parameter of the ADAMS/Solver. The result of the dynamics simulation is also used to test whether the parameters are defined properly or not. With this method, we find a better way to define the parameters in ADAMS.

Dynamics analysis of dual-axis positioning mechanism of satellite antenna with joint clearance

2014 ◽  
Vol 10 (1) ◽  
pp. 59-74
Author(s):  
Zheng Feng Bai ◽  
Yang Zhao ◽  
Jun Chen
Keyword(s):  
Dynamic Characteristics ◽  
Dynamic Performance ◽  
Engineering Application ◽  
Friction Model ◽  
Joint Clearance ◽  
Force Model ◽  
Dynamics Analysis ◽  
Satellite Antenna ◽  
Content Type ◽  
Continuous Contact

Purpose – The existence of clearance in joints of positioning mechanism is inevitable and the movements of the real mechanism are deflected from the ideal mechanism due to the clearances. The purpose of this paper is to investigate the effects of clearance on the dynamic characteristics of dual-axis positioning mechanism of a satellite antenna. Design/methodology/approach – The dynamics analysis of dual-axis positioning mechanism with clearance are investigated using a computational approach based on virtual prototyping technology. The contact model in joint clearance is established by using a hybrid nonlinear continuous contact force model and the friction effect is considered by using a modified Coulomb friction model. Then the numerical simulation of dual-axis positioning mechanism with joint clearance is carried out and four case studies are implemented for different clearance sizes. Findings – Clearance leads to degradation of the dynamic performance of the system. The existence of clearance causes impact dynamic loads, and influences the motion accuracy and stability of the dual-axis positioning mechanism. Larger clearance induces higher frequency shakes and larger shake amplitudes, which will deteriorate positioning accuracy. Practical implications – Providing an effective and practical method to analyze dynamic characteristics of dual-axis positioning mechanism of satellite antenna with joint clearance and describing the dynamic characteristics of the dual-axis positioning system more realistically, which improves the engineering application. Originality/value – The paper is the basis of mechanism design, precision analysis and robust control system design of dual-axis positioning mechanism of satellite antenna.

Dynamic Simulation Research of Jaw Crusher with Multi-Joint Clearance

2014 ◽  
Vol 644-650 ◽  
pp. 2678-2681
Author(s):  
Shao Jun Bo ◽  
Xiao Wang ◽  
Qing Huai Ye
Keyword(s):  
Contact Force ◽  
Simulation Software ◽  
Dynamics Simulation ◽  
Joint Clearance ◽  
Simulation Research ◽  
Jaw Crusher ◽  
Short Period ◽  
Characteristics Analysis ◽  
Dynamics Models ◽  
Dynamic Characteristics Analysis

On the basis of dynamics simulation software ADAMS, we built dynamics models of jaw crusher with multi-joint clearance. Contrast the link’s displacement, velocity, acceleration and the contact force between deputy campaign elements of the single joint clearance with the double joint clearance. Because the coupling superimposed of the double joint clearance, the velocity, acceleration and contact force is more complex. The whole is greater than the consideration of only a single joint clearance .But in some short period of time, there will be an acceleration that the contact force of the double joint clearance less than the single joint clearance. The dynamic characteristics analysis of multi-joint clearance is closer to the actual work of crusher.It can provide a theoretical basis for the control and optimization of the jaw crusher .

scholarly journals Analysis of dynamic characteristics for momentum wheel assembly with joint clearance

2018 ◽  
Vol 10 (12) ◽  
pp. 168781401881891
Author(s):  
Qi Wan ◽  
Geng Liu ◽  
Haitao Shi ◽  
Xiaofeng Zhang ◽  
Xin Ning
Keyword(s):  
Friction Coefficient ◽  
Angular Velocity ◽  
Dynamic Model ◽  
Contact Force ◽  
Dynamic Characteristics ◽  
Angular Acceleration ◽  
Friction Model ◽  
Joint Clearance ◽  
Force Model ◽  
Coulomb’S Friction

To study the effects of joint clearance on the dynamic characteristics of the momentum wheel assembly of satellite antennas, the computational dynamic model of momentum wheel assembly is developed in this article, considering influencing factors including rotor imbalance, flexibility, and joint clearance between rotor and bearing. The nonlinear contact force model and modified Coulomb’s friction model are adopted in the joint clearance of the dynamic model, and then the influence of clearance size, driving angular velocity, and friction coefficient on the dynamic behaviors of momentum wheel assembly is further analyzed. The results indicate that the existence of joint clearance has extraordinary obvious effects on the dynamic system characteristics, which causes the adjusting time to reach a state of continuous fluctuation to become longer compared to that of the ideal joint, and the angular acceleration and contact force appear to have high impulse peaks. The larger the clearance, the more obvious the fluctuation amplitude of the response and the slighter the shaking frequency. Furthermore, increasing the driving angular velocity can cause system oscillation with high frequency and large amplitude. Moreover, the smaller the friction coefficient, the poorer the accuracy and stability of the system, which leads to deviation from ideal performance. Therefore, it is important to consider the joint clearance to predict the dynamic characteristics of momentum wheel assembly.

Dynamic characteristics of planar linear array deployable structure based on scissor-like element with joint clearance using a new mixed contact force model

2016 ◽  
Vol 230 (18) ◽  
pp. 3161-3174 ◽  
Author(s):  
Bo Li ◽  
San-Min Wang ◽  
Ru Yuan ◽  
Xiang-Zhen Xue ◽  
Chang-Jian Zhi
Keyword(s):  
Contact Force ◽  
Dynamic Characteristics ◽  
Dynamic Performance ◽  
Equations Of Motion ◽  
Contact Model ◽  
Joint Clearance ◽  
Force Model ◽  
Continuous Contact ◽  
Deployable Structure ◽  
Contact Force Model

This paper aims at investigating precisely the dynamic performance of deployable structure constituted by scissor unit mechanisms with clearance joint. Based on the motion law in real joints, the contact model is established using an improved Gonthier nonlinear continuous contact force model, and the friction effect is considered using LuGre model. Moreover, the resulting contact force is suitable to be included into the generalized force of the equations of motion of a multibody system and contributes to replace motion constraints. In the sequel of this process, the effect of joint clearance is successfully introduced into the dynamical model of scissor deployable structure and the dynamic characteristics of deployable structure with joint clearance are obtained using a direct default correction method, which can directly modify the coordinates and speed of the system to avoid the numerical results divergence. Also, the new hybrid contact force model of revolute joint clearance is verified through comparing with the original model. The numerical simulation results show that the improved contact model proposed here has the great merit that predicts the dynamic behavior of scissor deployable structure with joint clearance.

scholarly journals A rough surface damping contact model and its application in spatial variable stator vane mechanism with dry friction joint

2021 ◽  
Author(s):  
Shuai Cheng ◽  
Xianghui Meng ◽  
Rui Li ◽  
Ruichao Liu ◽  
Rui Zhang
Keyword(s):  
Contact Force ◽  
Dry Friction ◽  
Contact Model ◽  
Dynamics Simulation ◽  
Joint Clearance ◽  
Force Model ◽  
Calculation Process ◽  
Stator Vane ◽  
Friction Joint ◽  
Variable Stator

Abstract For the mechanical system without oil lubrication, the impact or collision often occurs in the joint clearance, such as the variable stator vane (VSV) mechanism. In the dry friction joint, the damping of the contact bodies has a significant effect on the simulation stability of the tribo-dynamics calculation process. In order to investigate the effect of contact damping and joint clearance on the VSV mechanism performance, this paper proposes a damping contact model on rough surfaces to calculate the clearance contact force between the trunnion and bushing, and the spatial tribo-dynamics of VSV is established by combining this model with spatial dynamics. In addition, the effect of clearance size on the tribo-dynamics is analyzed. The results show that the contact damping must be included in the contact force model of dry friction joints, otherwise the calculation process will oscillate or even not converge, but the contact damping effect can be ignored in the case of lubricating oil. The movement of the trunnion in the bushing is affected by the adjustment drive and the aerodynamic drag, which leads to the wear concentrated on the edge of the bushing. The clearance size affects the distribution of the damping forces and the rigid forces in the contact process, and the damping forces ensure the stability of the VSV tribo-dynamics simulation process. Moreover, with the increase of clearance, the adjustment accuracy of the VSV mechanism is reduced, and the wear of the bushing is intensified.

scholarly journals Nonlinear Dynamic Characteristics Analysis of Shift Manipulator for Robot Driver with Multiple Joint Clearance

2021 ◽  
Author(s):  
Gang Chen ◽  
Xinyao Xu
Keyword(s):  
Dynamic Characteristic ◽  
Contact Force ◽  
Dynamic Characteristics ◽  
Nonlinear Dynamic ◽  
Force Model ◽  
Characteristic Model ◽  
Clearance Joints ◽  
Clearance Joint ◽  
Nonlinear Dynamic Characteristics ◽  
Nonlinear Dynamic Characteristic

Abstract The clearance joint is very important to the nonlinear dynamic characteristics of mechanism. This paper presents a nonlinear dynamic characteristic model of shift manipulator for robot driver based on multiple revolute clearance joints to improve dynamic characteristics. The relative penetration depth and velocity between pin and bushing are obtained by establishing the kinematic model of the shift manipulator with clearance joint. Based on the improved L-N contact force model and the modified Coulomb friction model, the normal contact force and the tangential contact force of clearance joint are analyzed. With full clearance joints, the nonlinear dynamic characteristic model of the shift manipulator for robot driver is established. The nonlinear dynamic characteristic laws of the shift manipulator including the end displacement, velocity, acceleration and active joint driving torque are analyzed by different sizes of clearance joints. And the performance test of the shift manipulator for robot driver is conducted. The results demonstrate that the nonlinear dynamic characteristics are well analyzed and verified through the presented characteristic model with clearance joints.

Dynamics Simulation Research of Planar Four-Bar Mechanism with Multi-Joint Clearance

2014 ◽  
Vol 599-601 ◽  
pp. 539-542 ◽  
Author(s):  
Shao Jun Bo ◽  
Zhen Jiu Si ◽  
Qing Huai Ye
Keyword(s):  
Contact Force ◽  
Coulomb Friction ◽  
Simulation Software ◽  
Dynamics Simulation ◽  
Joint Clearance ◽  
Simplified Model ◽  
Simulation Research ◽  
Object Movement ◽  
Preliminary Study ◽  
The Impact

On the basis of dynamics simulation software ADAMS,using a simplified model of crank-rocker mechanism with gravitational field for the study.It built the model of contact force and the coulomb friction [1,2] to simulate the motion pair with clearance.This paper made a preliminary study on the effect of the multi-joint clearance on the dynamics characteristics of the institution.The result showed that mechanism with double joint clearance had little influence on the mechanism speed and had relatively large impact on mechanism acceleration.Mechanism with three joint clearance increased the impact on the speed and acceleration appeared greater fluctuation and changes in direction.However,the contact force with three joint clearance was more stable and smaller than mechanism with double joint clearance. This kind of model is closer to the object movement in reality, so it can predict the laws of motion and provides more reliable theoretical reference for precision、optimization and noise prevention design of institutions.

Dynamics analysis of 2-DOF complex planar mechanical system with joint clearance and flexible links

2018 ◽  
Vol 93 (3) ◽  
pp. 1009-1034 ◽  
Author(s):  
Xiulong Chen ◽  
Shuai Jiang ◽  
Yu Deng ◽  
Qing Wang
Keyword(s):  
Mechanical System ◽  
Joint Clearance ◽  
Dynamics Analysis ◽  
Flexible Links
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