Dynamic analysis of open-loop mechanisms with multiple spatial revolute clearance joints

2018 ◽  
Vol 233 (2) ◽  
pp. 593-610 ◽  
Author(s):  
Lixin Yang ◽  
Xianmin Zhang ◽  
Yanjiang Huang
Keyword(s):  
Nonlinear Dynamic ◽  
Robot Manipulator ◽  
Equations Of Motion ◽  
Correction Method ◽  
Open Loop ◽  
Hertzian Contact ◽  
Dynamic Behaviors ◽  
Clearance Joints ◽  
Revolute Clearance Joint ◽  
Clearance Joint

Dynamic model of a typical open-loop mechanism with multiple spatial revolute clearance joints were established based on the Newton–Euler equations and the Hertzian contact deformation theory. An augmented constraint violation correction method was presented to solve the nonlinear dynamic equations of motion, which improved the global convergence and stability effectively. The nonlinear dynamic behaviors of a serial robot manipulator with two spatial revolute clearance joints were studied to demonstrate the effects of the location and coupling relationship of the clearance joints. Numerical results show that the influence of spatial revolute clearance joint on the dynamic behaviors of the open-loop mechanism is relatively stronger than that of the planar ones. The location of the spatial revolute clearance joints is an important factor to dynamic behavior of the system. The closer the spatial revolute clearance joint is to the end-effector, the stronger influence it has on the system. The spatial revolute clearance joints interact significantly with each another, which exhibits vigorous vibration with a higher frequency, larger amplitude, and deeper penetration. This work provides new insights into investigating the nonlinear dynamic behaviors of the systems with spatial revolute clearance joints.

The Effects of Bearing Stiffness on Nonlinear Dynamic Behaviors of Multi-Mesh Gear Train

2012 ◽  
Author(s):  
T. N. Shiau ◽  
T. H. Young ◽  
J. R. Chang ◽  
K. H. Huang ◽  
C. R. Wang
Keyword(s):  
Chaotic Motion ◽  
Nonlinear Dynamic ◽  
Equations Of Motion ◽  
Nonlinear Dynamic Analysis ◽  
Gear Train ◽  
Time Varying ◽  
Kutta Method ◽  
Dynamic Behaviors ◽  
Runge Kutta Method ◽  
Bearing Stiffness

In this study, the nonlinear dynamic analysis of the multi-mesh gear train with elastic bearing effect is investigated. The gear system includes the three rigid shafts, two gear pairs and elastic bearings. The stiffness and damper coefficient of elastic bearing are considered. The equations of motion of nonlinear time-varying system are derived using Lagrangian approach. The Runge-Kutta Method is employed to determine the system dynamic behaviors including the bifurcation and chaotic motion. The results show that the periodic motion, quasi-periodical motion and chaos can be excited with the elastic bearing effect. Especially, the results also indicate the dynamic response will go from periodic to quasi-periodical before the chaotic motion when the bearing stiffness is increased.

A methodology for dynamic behavior analysis of the slider-crank mechanism considering clearance joint

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Yu Chen ◽  
Jun Feng ◽  
Qiang He ◽  
Yu Wang ◽  
Yu Sun ◽  
...  
Keyword(s):  
Mechanical System ◽  
Dynamic Behavior ◽  
Equations Of Motion ◽  
Response Analysis ◽  
Force Model ◽  
Connecting Rod ◽  
Revolute Clearance Joint ◽  
Clearance Joint ◽  
Contact Impact ◽  
Crank Mechanism

Abstract The slider-crank mechanism is used widely in modern industrial equipment whereby the contact-impact of a revolute clearance joint affects the dynamic behavior of mechanical systems. Combining multibody dynamic theory and nonlinear contact theory, the computational methodology for dynamic analysis of the slider-crank mechanism with a clearance joint is proposed. The differential equations of motion are obtained considering the revolute clearance joint between the connecting rod and slider. In the mechanical system, the contact force is evaluated using the continuous force model proposed by Lankarani and Nikravesh, which can describe the contact-impact phenomenon accurately. Then, the experimental study is performed whereby the numerical results are compared with the test data to validate the proposed model. Moreover, the dynamic response analysis is conducted with various driving velocities and clearance sizes, which also explains that the sensitive dependence of a mechanical system on the revolute clearance joint.

scholarly journals Nonlinear Dynamic Analysis of Rotor-Bearing System with Cubic Nonlinearity

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Guofang Nan ◽  
Yujie Zhu ◽  
Yang Zhang ◽  
Wei Guo
Keyword(s):  
Nonlinear Dynamic ◽  
Nonlinear Dynamic Analysis ◽  
Hertzian Contact ◽  
Stable Operation ◽  
Nonlinear Stiffness ◽  
Cubic Nonlinearity ◽  
Dynamic Behaviors ◽  
Mass Eccentricity ◽  
Rotor Bearing ◽  
Bearing System

Nonlinear dynamic characteristics of a rotor-bearing system with cubic nonlinearity are investigated. The comprehensive effects of the unbalanced excitation, the internal clearance, the nonlinear Hertzian contact force, the varying compliance vibration, and the nonlinear stiffness of support material are considered. The expression with the linear and the cubic nonlinear terms is adopted to characterize the synthetical nonlinearity of the rotor-bearing system. The effects of nonlinear stiffness, rotating speed, and mass eccentricity on the dynamic behaviors of the system are studied using the rotor trajectory diagrams, bifurcation diagrams, and Poincaré map. The complicated dynamic behaviors and types of routes to chaos are found, including the periodic doubling bifurcation, sudden transition, and quasiperiodic from periodic motion to chaos. The research results show that the system has complex nonlinear dynamic behaviors such as multiple period, paroxysmal bifurcation, inverse bifurcation, jumping phenomena, and chaos; the nonlinear characteristics of the system are significantly enhanced with the increase of the nonlinear stiffness, and the material with lower nonlinear stiffness is more conducive to the stable operation of the system. The research will contribute to a comprehensive understanding of the nonlinear dynamics of the rotor-bearing system.

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.

Nonlinear dynamic characteristics and control of planar linear array deployable structures consisting of scissor-like elements with revolute clearance joint

2020 ◽  
pp. 136943322097172
Author(s):  
Bo Li ◽  
San-Min Wang ◽  
Charis J Gantes ◽  
U-Xuan Tan
Keyword(s):  
Friction Coefficient ◽  
Contact Force ◽  
Initial Conditions ◽  
Equations Of Motion ◽  
Force Model ◽  
Deployable Structures ◽  
Clearance Joints ◽  
Continuous Contact ◽  
Clearance Joint ◽  
Parametric Effects

This paper comprehensively deals with the parametric effects of the joint clearance and friction coefficient on the dynamics of planar deployable structures consisting of scissor-like elements (SLEs). The dynamic model for scissor deployable structure is based on a comprehensive consideration of the symmetry and array characteristics of this mechanism and on a Lagrange method, which represents the motion equations. A modified nonlinear contact-force model is employed to evaluate the intrajoint contact force, and the incorporation of the friction effect between the inter-connecting bodies is included in this study. The total impact forces produced in the real mechanical joint are embedded into the dynamics and the differential equations of motion are solved numerically based on a set of initial conditions. The clearance size, angle velocity, and friction coefficient are analyzed and discussed separately. Using Poincaré map, the regular and irregular responses of the deployable mulitibody systems are observed. Next, a control scheme is evaluated to maintain a more stable behavior and continuous contact between the clearance joints. The controlled results are compared with those without control, concluding that some undesired effects caused by the clearance joints can be prevented or reduced, resulting in continuous contact at the clearance joint.

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.

Wave Analysis of Planar Deployable Structures with Revolute Clearance Joints Based on Spectral Element Method

2018 ◽  
Vol 10 (08) ◽  
pp. 1850090 ◽  
Author(s):  
Xiao-Fei Ma ◽  
Tuan-Jie Li
Keyword(s):  
Spectral Element Method ◽  
Impact Load ◽  
Spectral Element ◽  
Wave Analysis ◽  
Clearance Joints ◽  
Revolute Clearance Joint ◽  
Planar Structures ◽  
Clearance Joint ◽  
The Impact ◽  
Element Method

Clearance is inevitable in the deployable mechanisms due primarily to the kinematic function requirements. This phenomenon affects the dynamic performances of deployed structures negatively. In this paper, the wave analysis of dynamic characteristics of planar structures with revolute clearance joints is developed by spectral element method. First, the spectral element model of revolute clearance joints is established. The radial and tangential springs and damping coefficients of revolute clearance joints are evaluated based on the contact model of elastic foundation. Then, the wave equations of two beams connected by a revolute clearance joint are derived, and extended to the case of multiple beams connected by revolute clearance joints. Finally, the dynamic response is analyzed for planar structures with single revolute clearance joint and multiple revolute clearance joints under the impact load. The wave propagation rules in planar structures with revolute clearance joints are revealed.

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.

Dynamic analysis of mechanical system considering radial and axial clearances in 3D revolute clearance joints

2020 ◽  
pp. 107754632095051
Author(s):  
Zheng Feng Bai ◽  
Xin Jiang ◽  
Ji Yu Li ◽  
Ji Jun Zhao ◽  
Yang Zhao
Keyword(s):  
Mechanical System ◽  
Dynamic Characteristics ◽  
Mathematic Model ◽  
Contact Forces ◽  
Dynamic Responses ◽  
Radial Clearance ◽  
Double Pendulum ◽  
Clearance Joints ◽  
Revolute Clearance Joint ◽  
Clearance Joint

In the dynamic modeling and simulation of mechanical system with revolute clearance joint, it is usually assumed that the revolute joint is planar joint with radial clearance, but the axial clearance is ignored. In this article, the dynamic responses of a mechanical system considering both radial and axial clearances in 3D revolute clearance joint are investigated using a computational methodology. First, the mathematic model of 3D revolute clearance joint is established considering the radial and axial clearances. The definitions of the radial and axial clearances, the potential contact modes, contact conditions, and contact detection for 3D revolute clearance joint are presented. Furthermore, the normal and tangential contact force models are established to describe the contact phenomenon and determine the contact forces in revolute clearance joints. Finally, two demonstrative application examples are presented to illustrate the dynamic characteristics of mechanical systems considering both radial and axial clearances in revolute clearance joints. A slider-crank mechanism with planar motion and a double pendulum with spatial motion are investigated. Different cases are presented to analyze the dynamic characteristics of a mechanical system considering radial and axial clearances in 3D revolute clearance joints.

Dynamics Analysis of Spatial Mechanisms with Dry Spherical Joints with Clearance Using Finite Particle Method

2020 ◽  
Vol 20 (03) ◽  
pp. 2050035
Author(s):  
Yanfeng Zheng ◽  
Chao Yang ◽  
Hua-Ping Wan ◽  
Yaozhi Luo ◽  
Yang Li ◽  
...  
Keyword(s):  
Friction Force ◽  
Equations Of Motion ◽  
Particle Method ◽  
Practical Method ◽  
Dynamic Responses ◽  
Dynamic Effects ◽  
Clearance Joints ◽  
Spatial Mechanisms ◽  
Clearance Joint ◽  
Finite Particle

The presence of clearance in a spherical joint makes the ball of the joint easy to collide with the socket, which causes additional dynamic effects on the motion of spatial mechanisms. The complexity of interaction between different clearance joints and that between a clearance joint and connected component requires an effective analysis method. In this paper, a practical method is proposed for evaluating the dynamic effects of spatial flexible mechanisms with multiple spherical clearance joints using finite particle method (FPM) combined with a clearance contact model. First, the equations of motion of the particles and internal force formulas of spatial beam elements in the discretized FPM model are derived, and the explicit generalized-[Formula: see text] method is adopted for time integration. Then, the contact state is detected based on the penetration depth, using the Lankanani–Nikravesh model to calculate the contact force and the Threlfall model to calculate the friction force during collision in the clearance joint. Specifically, a method considering the particle rotations is utilized to better evaluate the direction of the friction force. A spatial four-bar mechanism with spherical clearance joints is used to demonstrate the feasibilities of the proposed method. The effects of four parameters (i.e. clearance size, friction coefficient, multiple clearance joints, and bending stiffness) on the dynamic responses of the mechanism are fully investigated.

Sign in / Sign up

Export Citation Format

Share Document