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.

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.

scholarly journals Investigation on Dynamics of Mechanical System with Clearance Joint

2014 ◽  
Vol 8 (1) ◽  
pp. 224-229
Author(s):  
Zheng-Feng Bai ◽  
Bin-jiu Yang ◽  
Yi Sun
Keyword(s):  
Mechanical System ◽  
Frequency Domain Analysis ◽  
Friction Model ◽  
Dynamic Responses ◽  
Force Model ◽  
Clearance Joints ◽  
Continuous Contact ◽  
Clearance Joint ◽  
Joint Contact ◽  
Coulomb Friction Model

In this work, the dynamic responses and vibration characteristics of mechanical system with revolute clearance joints are investigated numerically. Considering clearance in joint, the intra-joint contact model that is generated at clearance joints is established using a nonlinear continuous contact force model and the friction effect is considered by using a modified Coulomb friction model. A well-known slider-crank mechanism with a revolute clearance joint is utilized to perform the investigation. The effects of clearance on dynamics of mechanical system are analyzed by timedomain responses and frequency domain analysis. The investigation results show that the dynamic responses of mechanical system with clearance are obviously vibration and the amplitude increases from the mechanism without clearance. The results also indicate that the behavior of mechanism with clearance is nonlinear.

Dynamic characteristics of planar linear array deployable structure based on scissor-like element with differently located revolute clearance joints

2017 ◽  
Vol 232 (10) ◽  
pp. 1759-1777 ◽  
Author(s):  
Bo Li ◽  
San-Min Wang ◽  
Viliam Makis ◽  
Xiang-Zhen Xue
Keyword(s):  
Mechanical System ◽  
Dynamic Characteristics ◽  
Equations Of Motion ◽  
Nonlinear Behavior ◽  
Friction Model ◽  
Dynamic Responses ◽  
Force Model ◽  
Clearance Joints ◽  
Deployable Structure ◽  
Clearance Joint

This paper comprehensively investigates the parametric effects of differently located revolute clearance joints on the dynamic behavior of planar deployable structure based on scissor-like element. Considering the real physical mechanical joints, the normal and the tangential forces in the revolute clearance joints are respectively modeled using Flores contact-force model and LuGre friction model. The resulting forces and moments are embedded in the equations of motion of the scissor deployable structure for accurately describing the effect of joint clearance and governing the dynamic response of this structure. The effects of the main parameters such as the location of the clearance joint, the clearance size and the number of clearance joints on the dynamic characteristics of a multibody mechanical system have been numerically evaluated, and the results indicate that joints at different locations in a mechanical system have different sensitivities to the clearance size, and the more sensitive joint should be controlled to reduce the nonlinear behavior of this structure. Also, it can be concluded that the motion in one revolute clearance joint will affect the motion in the other clearance joints and the dynamic interaction of clearance joints is the important source of structural behavior change. Therefore, in order to accurately predict the dynamic responses of the mechanical system, the clearance effect of each joint on the multibody system should be investigated and understood.

Wear Analysis of Spatial Parallel Mechanisms With Multiple Three-Dimensional Spherical Clearance Joints

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Chen Xiulong ◽  
Jia Yonghao
Keyword(s):  
Parallel Mechanism ◽  
Surface Profile ◽  
Friction Model ◽  
Dynamic Responses ◽  
Force Model ◽  
Parallel Mechanisms ◽  
Clearance Joints ◽  
Wear Analysis ◽  
Clearance Joint ◽  
Analysis Of Dynamics

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.

scholarly journals Dynamic Analysis of a Planar Hydraulic Rock-Breaker Mechanism with Multiple Clearance Joints

2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Ke Chen ◽  
Guojun Zhang ◽  
Rui Wu ◽  
Li Wang ◽  
Hongmei Zheng ◽  
...  
Keyword(s):  
Hydraulic Cylinder ◽  
Dynamic Responses ◽  
Force Model ◽  
Engineering Applications ◽  
Mass System ◽  
Clearance Joints ◽  
Cylinder Model ◽  
Practical Engineering ◽  
Manufacturing Tolerances ◽  
Joint Clearances

Clearance exists in the joint of a mechanism because of the assemblage, manufacturing tolerances, wear, and other conditions, and it is a focus of research in the field of multibody dynamics. This study built a planar hydraulic rock-breaker model with multiple joint clearances by combining the hydraulic cylinder model, the clearance joints based on the Lankarani–Nikravesh contact force model, and the Lagrange multiplier method. Dynamic simulation results indicated that multiple clearance joints can degrade the dynamic responses of a rock-breaker model, which can be decomposed to rapid vibrations and slow movements. The rapid vibrations are excited by coupling the spring-mass system of hydraulic cylinder and clearances. The effects of the clearance size, input force, damping coefficient, and friction on the dynamic behaviour of the rock-breaker mechanism are also investigated. The friction could reduce the rapid vibration state significantly, which is feasible for practical engineering applications. As compared with the traditional models without clearances, the present model provides not only better predictions for the theoretical study of the hydraulic rock-breaker but also useful guidance for reducing the vibrations of the hydraulic rock-breaker in practical engineering applications.

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.

Dynamic analysis of a planar multibody system with multiple revolute clearance joints

2018 ◽  
Vol 233 (10) ◽  
pp. 3429-3443 ◽  
Author(s):  
Xupeng Wang ◽  
Wenzhou Lin ◽  
Xiaomin Ji ◽  
Zhu Gao ◽  
Xiaobo Bai ◽  
...  
Keyword(s):  
Multibody System ◽  
Dynamic Responses ◽  
Force Model ◽  
Nonlinear Phenomenon ◽  
Linkage Mechanism ◽  
Clearance Joints ◽  
Clearance Joint ◽  
Four Bar Linkage ◽  
The Impact ◽  
The Ideal

This paper focuses on the dynamic responses of a planar mechanism with multiple clearance joints. The effect of the impact between the journal and the bearing in the clearance joint is described using an improved impact force model, and a typical four-bar linkage mechanism with multiple clearance joints is presented as an example. Two conditions are considered in this research, one is the single clearance joint with different position, and the other is multiple clearance joints. From a large number of numerical results, some important conclusions are obtained as follows: (1) with the influence of the clearance joint, the dynamic output of system has obvious vibration in comparison to the ideal value. (2) The position of the clearance joint has a clear effect on the response of system; the larger the distance of the clearance joint from the drive motor, the smaller its influence on the output of the system. (3) With the increase in the clearance joint number, the dynamic stability of the multibody system is decreased gradually, and the dynamic characteristic of the system also appears as obvious nonlinear phenomenon. (4) The coupling phenomenon appears when multiple clearance joints in the multibody system are considered, which should be examined seriously during the process of design and numerical analysis.

scholarly journals A Study on Clearance Effects on Dynamic Responses of Robot Manipulator

Mechanika ◽  
2021 ◽  
Vol 27 (2) ◽  
pp. 130-138
Author(s):  
Zhengfeng Bai ◽  
Tianxi LIU
Keyword(s):  
Contact Force ◽  
Robot Manipulator ◽  
Dynamic Responses ◽  
Joint Clearance ◽  
Force Model ◽  
Clearance Joints ◽  
Clearance Joint ◽  
Dynamic Performances ◽  
Simulation Results ◽  
The Impact

Clearances caused by assemblage, manufacturing errors and wear, affect inevitably the dynamic responses of mechanisms such as robot manipulator. In this study, the effects of clearance on a robot manipulator system are investigated numerically. The contact behavior along normal and tangential direction of clearance joint is described by a nonlinear contact force model and a modified Coulomb friction model respectively. Then, the dynamics equations of the robot manipulator system are established considering joint clearance. In order to investigate the effects of clearance on dynamic performances of practical mechanism, a planar robot manipulator system on a spacecraft system with a revolute clearance joint is used as the apply example. Four case studies for various clearance sizes are implemented to investigate and discuss the effects of joint clearance. The simulation results indicate that clearance joints have severe effects on the dynamic performances of mechanism system and the impact in clearance joints represented by contact force models must be considered in dynamics analysis and design of mechanism system. The simulation results in this work can predict the effects of clearance on robot manipulator system preferably and it is the basis of precision analysis, robust control system design of robot manipulator system.

Dynamics Analysis of Truss Deployment Mechanism With Imperfect Joint Considering Input Fluctuation

2020 ◽  
Author(s):  
Zhengfeng Bai ◽  
Jijun Zhao ◽  
Xin Shi
Keyword(s):  
Contact Force ◽  
Dynamic Performance ◽  
Mathematic Model ◽  
Friction Model ◽  
Dynamic Responses ◽  
Force Model ◽  
Normal Contact ◽  
Clearance Joint ◽  
Contact Force Model ◽  
Dynamic Performance Analysis

Abstract Modern spacecraft usually has large deployment structure, which consisting of plenty of joints could produce undesirable dynamic responses when considering clearances in joints and driving input fluctuation. However, in the dynamic performance analysis of space deployment mechanism, the clearances and input fluctuation are always ignored. In this study, the dynamic responses of a flexible planar scissor-like truss deployment mechanism with imperfect joint considering clearance and input fluctuation are investigated using computational methodology. First, the mathematic model of clearance joint is established. The revolute clearance joint is considered as force constraint and the joint components of an imperfect joint with clearance are modeled as contact bodies. The normal contact force model of clearance joint is established using a continuous contact force model considering energy loss. The friction effect is considered using a modified Coulomb friction model. Then, the dynamics performances of the flexible planar scissor-like truss deployment mechanism with imperfect joint considering clearance and input fluctuation are presented and discussed. Different case studies for the scissor-like truss deployment mechanism with clearance are investigated considering driving input fluctuation. The simulation results show that the dynamic characteristics of the mechanism with clearance joint are changed more obviously when considering driving input fluctuation. Therefore, investigation implies that dynamics responses of the truss deployment mechanism are much worse when considering clearance joint and input fluctuation, which indicates that driving input fluctuation leads to more obvious degradation of the dynamic performance of the truss deployment mechanism with imperfect joint.

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