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.

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.

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 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.

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.

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.

A 2D Bristle Friction Force Model for Contact Dynamics Simulation

2009 ◽  
Author(s):  
Ou Ma ◽  
Jianxun Liang ◽  
Steven Fillmore
Keyword(s):  
Contact Point ◽  
Friction Model ◽  
Contact Dynamics ◽  
Dynamics Simulation ◽  
Contact Friction ◽  
Force Model ◽  
Tangential Plane ◽  
Friction Forces ◽  
Body Contact ◽  
Frictional Behavior

This paper describes a 2D bristle contact friction model which is capable of modeling and simulating frictional behavior in both sliding and sticking regimes occurring in general 3D rigid-body contact. The model extends the 1D integrated bristle friction model to a 2D space by allowing the “bristle spring” to not only stretch along the direction of the relative velocity but also rotate due to the direction change of the velocity or motion trend in the common tangential plane of the contacting surfaces involved at the contact point of interest. With such an extension, the resulting friction model can be readily used to compute 3D contact friction forces in both sticking and sliding regimes for a general 3D contact dynamics model working with a multibody dynamics simulation application. Several simulation examples are provided to demonstrate the effectiveness of the model for predicting the experimentally seen frictional behavior such as sticking, stickslip, and sliding.

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.

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.

Effects of Mechanical Flexibility and Clearance Size on the Wear at Revolute Joint in the Flexible Multibody Systems

2014 ◽  
Author(s):  
Bo Zhao ◽  
Xudong Dai ◽  
Shihao Wu
Keyword(s):  
Contact Force ◽  
Numerical Approach ◽  
Friction Model ◽  
Force Model ◽  
Wear Prediction ◽  
Normal Contact ◽  
Continuous Contact ◽  
Clearance Joint ◽  
Flexible Multibody ◽  
Flexible Component

By integrating the procedures of wear prediction with multibody dynamics, this paper proposed a numerical approach for the modeling and prediction of wear at revolute clearance joint in flexible multibody mechanical systems. In the approach, the flexible component was modeled by using absolute nodal coordinate formulation (ANCF)-based element. The clearance joint was modeled as a dry contact pair, in which the continuous contact force model proposed by Lankanrani and Nikravesh was applied to evaluate the normal contact force, and the friction effect was considered using the LuGre friction model. The calculation of wear was performed by an iterative wear prediction procedure based on Archard’s wear model. Using this approach, a planar slider-crank mechanism including a flexible rod and clearance joint was numerically investigated as a demonstrative example. Furthermore, the effects of the flexibility of the mechanism and the clearance size on the wear at clearance joint were also studied.

Sign in / Sign up

Export Citation Format

Share Document