scholarly journals Dynamic Responses of Planar Multilink Mechanism considering Mixed Clearances

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Xiulong Chen ◽  
Shuai Jiang ◽  
Yu Deng
Keyword(s):  
Great Influence ◽  
Friction Model ◽  
Contact Forces ◽  
Dynamic Responses ◽  
Prototype Model ◽  
Planar Mechanisms ◽  
Coulomb’S Friction ◽  
Revolute Joints ◽  
Friction Models ◽  
Coulomb Friction Model

Translational and revolute joints are the main kinds of joints in planar multilink mechanisms. Translational and revolute clearance joints have great influence on dynamical responses of planar mechanisms. Most research studies mainly focused upon revolute clearance of planar mechanisms based upon the modified Coulomb friction model, some studies investigated clearance of the pin-slot joint, and few studies researched mixed clearances (considering both translational clearance and revolute clearance) based on the LuGre friction model. Dynamic response of the 2-DOF nine-bar mechanism considering mixed clearances based on the LuGre model is investigated in this work. The dynamic model with mixed clearances is built by the Lagrange multipliers. Dynamic responses including motion output of the slider, driving torques, contact forces, shaft center trajectories at revolute clearance pairs, and slider trajectory inside the guide are analyzed, respectively. Influences of different friction models on dynamic responses are studied, such as LuGre and modified Coulomb’s friction models. Effects of different clearance values and different driving speeds on dynamic responses with mixed clearances are both analyzed. Virtual prototype model considering mixed clearances is carried out through ADAMS to verify correctness.

scholarly journals Investigation on Dynamic Interaction of Multiple Clearance Joints for Flap Actuation System

2020 ◽  
Vol 306 ◽  
pp. 01001
Author(s):  
Qi Wan ◽  
Liu Geng ◽  
Shangjun Ma ◽  
Ruiting Tong
Keyword(s):  
Stable State ◽  
Dynamic Interaction ◽  
Friction Model ◽  
Dynamic Responses ◽  
Force Model ◽  
Clearance Joints ◽  
Actuation System ◽  
Rigid Connection ◽  
Dynamic Simulation Model ◽  
Coulomb Friction Model

A dynamic simulation model of the flap actuation system is developed in this paper to analyze the dynamic interaction behaviours of multiple clearance joints. The nonlinear contact force model and modified Coulomb friction model are adopted in the four clearance joints to capture their motion modes, including free flight mode, impact mode and continuous mode. The results show that there exists a strong dynamic interaction between different clearance joints and one impact motion mode in a joint will immediately affect other joints. And when the system reaches a stable state, the four clearance joints almost appears the similar tendency due to the rigid connection. Therefore, in order to accurately predict the dynamic responses of multibody system, it is essential for all joints to be modelled as imperfect ones.

An Overview of Several Formulations for Dry and Lubricated Revolute Joint Clearances in Planar Rigid-Multi-Body Mechanical Systems

2014 ◽  
Author(s):  
Paulo Flores ◽  
Hamid M. Lankarani
Keyword(s):  
Numerical Models ◽  
Equations Of Motion ◽  
Mechanical Systems ◽  
Contact Forces ◽  
Hertzian Contact ◽  
Revolute Joint ◽  
Coulomb’S Friction ◽  
Revolute Joints ◽  
Joint Clearances ◽  
Multi Body

The influence of the revolute joint model on the dynamic response of planar multibody mechanical systems is studied in this work. In the sequel of this process, under the framework of the multibody formalisms, a general methodology for modeling the main kinematic aspects of dry revolute joint clearances is revisited. The numerical models for normal and tangential contact forces developed at the clearance joints are also discussed, which are based on the Hertzian contact theory and dry Coulomb’s friction law, respectively. The fundamental kinematic and dynamic issues of the modeling lubricated revolute joints are presented in this work in order to compare them with the dry revolute joint approach. In a simple manner, the lubrication forces are obtained by integrating the pressure distribution evaluated with the aid of Reynolds’ equation corresponding to the dynamic regime. The intra-joint forces developed for both dry and lubricated cases are evaluated based on the state of variable of the system and subsequently included into the dynamic equations of motion of the multibody system as external generalized forces. The main assumptions and procedures adopted throughout this work are demonstrated through simulations of a planar slider-crank mechanism, which includes dry and lubricated revolute joint with clearance. Finally, some experimental data is also presented and analyzed.

Comparison of numerical simulation results of sheet metal parts’ production for AutoForm and TriboForm friction models

2020 ◽  
pp. 359-372
Author(s):  
M.A. Petrov
Keyword(s):  
Sheet Metal ◽  
Metal Forming ◽  
Coulomb Friction ◽  
Friction Model ◽  
Metal Parts ◽  
Sheet Metal Parts ◽  
Friction Models ◽  
The Difference ◽  
Coulomb Friction Model

The results of numerical simulations with two friction models are studied. The fi rst model corresponded the Coulomb friction model and used in AutoForm on default. The second friction model took into account the quality of surface treatment, its roughness and amount of the lubricant and the effect of the asperities’ height evolution. It is used in TriboForm. The results obtained for the second friction model are used to simulate sheet metal forming processes in AutoForm. It is found that the TriboForm friction model affected the results of the drawing operation. The difference in the results increased due to bigger deformation values of the technological operation.

Friction in Double Action Extrusion

2009 ◽  
Vol 424 ◽  
pp. 153-160 ◽  
Author(s):  
Li Liang Wang ◽  
Jie Zhou ◽  
Jurek Duczczyk
Keyword(s):  
Coulomb Friction ◽  
Fem Simulation ◽  
Friction Model ◽  
Extrusion Force ◽  
Testing Method ◽  
Friction Factors ◽  
Wide Range ◽  
Shear Friction ◽  
Friction Models ◽  
Coulomb Friction Model

A novel extrusion testing method, double action extrusion (DAE), to highlight the effect of friction at the die bearing in aluminum extrusion was developed. It was found that the lengths of the extrudates and extrusion force were indeed sensitive to the die bearing length and thus to the friction. FEM simulations of DAE were carried out to evaluate the shear and Coulomb friction models over a wide range of friction factors/coefficients from 0.2 to 1. The full sticking friction appeared to represent the interfacial contact between hot aluminum and die the best. The friction factor values in the shear friction model over a range of 0.3 to 0.6 commonly used to describe the contact at the billet-die interface in FEM simulation appeared to be too low. The comparison between the experimental and simulation results indicated that the shear friction model at m = 1 predicted the extrusion force the best, while the Coulomb friction model at µ = 1 predicted the extrudate lengths the best. Of the existing friction models and friction factors/coefficients, it is recommended to use the shear friction model at m = 1 to describe the friction at the billet-die interface in FEM simulation.

scholarly journals Experimental comparison of five friction models on the same test-bed of the micro stick-slip motion system

2015 ◽  
Vol 6 (1) ◽  
pp. 15-28 ◽  
Author(s):  
Y. F. Liu ◽  
J. Li ◽  
Z. M. Zhang ◽  
X. H. Hu ◽  
W. J. Zhang
Keyword(s):  
Friction Model ◽  
Test Bed ◽  
Lugre Model ◽  
Stick Slip ◽  
Motion System ◽  
Friction Models ◽  
Micro Motion ◽  
Coulomb Friction Model ◽  
Stick Slip Motion ◽  
Slip Motion

Abstract. The micro stick-slip motion systems, such as piezoelectric stick-slip actuators (PE-SSAs), can provide high resolution motions yet with a long motion range. In these systems, friction force plays an active role. Although numerous friction models have been developed for the control of micro motion systems, behaviors of these models in micro stick-slip motion systems are not well understood. This study (1) gives a survey of the basic friction models and (2) tests and compares 5 friction models in the literature, including Coulomb friction model, Stribeck friction model, Dahl model, LuGre model, and the elastoplastic friction model on the same test-bed (i.e. the PE-SSA system). The experiments and simulations were done and the reasons for the difference in the performance of these models were investigated. The study concluded that for the micro stick-slip motion system, (1) Stribeck model, Dahl model and LuGre model all work, but LuGre model has the best accuracy and (2) Coulomb friction model and the elastoplastic model does not work. The study provides contributions to motion control systems with friction, especially for micro stick-slip or step motion systems as well as general micro-motion systems.

A Simplified Analytical Model of Rolling/Sliding Behavior and Friction in Four-Point-Contact Ball Bearings and Screws

2017 ◽  
Author(s):  
Bo Lin ◽  
Molong Duan ◽  
Chinedum E. Okwudire ◽  
Jason S. Wou
Keyword(s):  
Analytical Model ◽  
Contact Point ◽  
Point Contact ◽  
Contact Angles ◽  
Friction Model ◽  
Contact Forces ◽  
Ball Bearings ◽  
Contact Points ◽  
Pure Rolling ◽  
Coulomb Friction Model

Four-point contact between ball and raceways is common in machine elements like ball bearings and ball screws. The ideal four-point-contact machine element is designed with pure rolling (i.e., no sliding at contact points) to minimize friction. However, this ideal may not always be achieved, leading to sliding and higher frictional forces. In this paper, a simplified analytical model for rolling/sliding behavior and friction in four-point contact is developed, based on Coulomb friction model and rigid body assumption. It is found that pure rolling is only possible when the contact-point geometry satisfies a certain relationship. When pure rolling condition fails to hold, the sliding contact point(s) can be determined analytically as a function of contact forces and contact angles. Case studies are presented to demonstrate how the proposed model could elucidate the roles of misalignments, manufacturing errors and loading conditions on rolling/sliding behavior and friction.

Improved Dynamic Friction Models for Simulation of One-Dimensional and Two-Dimensional Stick-Slip Motion

2000 ◽  
Vol 123 (4) ◽  
pp. 661-669 ◽  
Author(s):  
Fitsum A. Tariku ◽  
Robert J. Rogers
Keyword(s):  
Mechanical Systems ◽  
Friction Model ◽  
Contact Forces ◽  
Force Balance ◽  
Two Dimensional ◽  
Lumped Mass ◽  
Stick Slip ◽  
Normal Contact ◽  
One Dimensional ◽  
Friction Models

In many mechanical systems, the tendency of sliding components to intermittently stick and slip leads to undesirable performance, vibration, and control behaviors. Computer simulations of mechanical systems with friction are difficult because of the strongly nonlinear behavior of the friction force near zero sliding velocity. In this paper, two improved friction models are proposed. One model is based on the force-balance method and the other model uses a spring-damper during sticking. The models are tested on hundreds of lumped mass-spring-damper systems with time-varying excitation and normal contact forces for both one-dimensional and two-dimensional stick-slip motions on a planar surface. Piece-wise continuous analytical solutions are compared with solutions using other published force-balance and spring-damper friction models. A method has been developed to set the size of the velocity window for Karnopp’s friction model. The extensive test results show that the new force-balance algorithm gives much lower sticking velocity errors compared to the original method and that the new spring-damper algorithm exhibits no spikes at the beginning of sticking. Weibull distributions of the sticking velocity errors enable maximum errors to be estimated a priori.

Transmission Characteristics Analysis of Spherical Hinge with Clearance

2014 ◽  
Vol 701-702 ◽  
pp. 803-806
Author(s):  
Ling Hua Xiong ◽  
Zhe Si Zhang
Keyword(s):  
Mechanical System ◽  
Working Conditions ◽  
Coulomb Friction ◽  
Friction Model ◽  
Prototype Model ◽  
Kinematic Pair ◽  
Transmission Characteristics ◽  
Characteristics Analysis ◽  
Coulomb Friction Model ◽  
Spherical Hinge

Spherical hinge as a kinematic pair is widely used in mechanical engineering, but clearance inevitably exists in it and reduces the run precision of the mechanical system. In this paper, two-mode theory of nonlinear spring-damper contact force and modified Coulomb friction model are used for creating a virtual prototype model of a kinematic pair with clearance. Drive force is calculated in 4 kinds of working conditions, 3 different sizes of clearance. Influence of the clearance on accuracy of the transmission force is discussed.

A Finite Element Study on Contact Pressure Distribution in Draw-Bend Friction Test and Its Effect on Friction Measurement

2005 ◽  
Author(s):  
Young Suk Kim ◽  
Don R. Metzger ◽  
Mukesh K. Jain
Keyword(s):  
Finite Element ◽  
Coulomb Friction ◽  
Friction Model ◽  
Friction Test ◽  
Friction Measurement ◽  
Explicit Finite Element ◽  
Constant Friction ◽  
Friction Models ◽  
Bend Tests ◽  
Coulomb Friction Model

Various experimental and numerical works have shown the existence of pressure peaks at the contact interface of draw-bend tests. From this observation, a need has been raised for the re-examination of the methodology to calculate the friction coefficient from the draw-bend friction test. In this paper, the draw-bend friction tests have been simulated by the explicit finite element method. By using 3D finite element models and local axis system, the existence of pressure peaks was confirmed. A non-constant friction model (Stribeck friction model), which is more realistic for sheet metal forming than a constant friction model (Coulomb friction model), was implemented into the finite element code. Simulations were performed with constant and non-constant friction models. From the comparisons, the effect of existence of pressure peaks on the friction measurement was evaluated.

Investigation on Dynamic Responses of Manipulator with Multiple Clearance Joints

2012 ◽  
Vol 251 ◽  
pp. 152-157
Author(s):  
Zheng Feng Bai ◽  
Xing Gui Wang ◽  
Yang Zhao
Keyword(s):  
Dynamic Performance ◽  
Friction Model ◽  
Contact Dynamics ◽  
Dynamic Responses ◽  
Dynamics Simulation ◽  
Force Model ◽  
Clearance Joints ◽  
The Real ◽  
Continuous Contact ◽  
Coulomb Friction Model

The existence of clearance in joints of manipulator system is inevitable and the movements of the real manipulator are deflection from the ideal manipulator for the clearances. In this study, the effects of clearance on dynamic responses of real manipulator system with multiple clearance joints are investigated using a computational methodology. By applying the nonlinear continuous contact force model, the contact dynamics model in joint clearance is established and the friction effect is considered with the help of Coulomb friction model. Then the dynamics simulation is carried out and the dynamic characteristics of manipulator system with multiple clearance joints are investigated. The results show that the clearance leads to degradation of dynamic performance of the real manipulator system.

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