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 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 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.

Stability Analysis and Optimal Design of High-Speed and High-Load Driving Mechanism With Joint Clearance Based on Multi-Body Dynamics

2013 ◽  
Author(s):  
Zenglei Zhang ◽  
Shijing Wu ◽  
Haibo Zhang ◽  
Jie Chen
Keyword(s):  
Optimal Design ◽  
Dynamic Characteristics ◽  
High Speed ◽  
High Load ◽  
Joint Clearance ◽  
Force Model ◽  
Driving Mechanism ◽  
Contact Method ◽  
Continuous Contact ◽  
Multi Body

High-speed and high-load driving mechanism with joint clearance presents strong nonlinear features which affects the dynamic characteristics of the mechanism. A single-degree-of-freedom multi-body model, including nine connecting links, three translation joints and ten revolute joints with clearance, is built with the continuous contact method based on research of dynamics theory about joint clearance. Furthermore, normal forces are calculated with a nonlinear continuous contact force model and tangential forces are calculated with the modified Coulomb friction model to simulate process of contact and collision. When the model is solved according to real operating condition, the results are compared with that of the model with ideal joints, finding that revolute joint clearance will create effects on velocity and especially great effects on acceleration of the driving mechanism. Moreover, different amounts and different sizes of the clearance are considered to research the influence on dynamic characteristics of the driving mechanism. Meanwhile, methods of optimal design are explored according to the parametric analysis computing results. Simulation methods and findings can act as guidance for further study of optimal design for high-speed and high-load driving mechanisms to reduce the negative effects of joint clearance.

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.

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.

Dynamic Response of Eccentric Swinging Sheet Transfer Mechanism with Kinematic Pair Clearances

2013 ◽  
Vol 312 ◽  
pp. 182-185
Author(s):  
Fang Cai ◽  
Jian Qing Zhang ◽  
Xiu Feng Ma
Keyword(s):  
Dynamic Response ◽  
Dynamic Characteristics ◽  
Dynamic Performance ◽  
Transfer Mechanism ◽  
Kinematic Pair ◽  
Nonlinear Dynamic Response ◽  
Nonlinear Characteristics ◽  
Continuous Contact ◽  
The Stability ◽  
Transfer Mechanisms

To research the influence of kinematic pair clearances on the dynamic performance of eccentric swinging sheet transfer mechanism used in Sheet-fed offset J2108, a dynamic model was established based on the clearances characteristics and the continuous contact hypothesis. Consequently, the dynamic characteristics of sheet transfer mechanisms output can be researched quantitatively. The results indicate that sheet transfer mechanisms dynamic response appears strong nonlinear characteristics while considering kinematic pair clearances, which seriously affects the sheet transfer mechanisms stability and precision. Therefore, the study on the nonlinear dynamic response of sheet transfer mechanism can provide foundation to improve the stability.

Analysis of dynamic characteristics of spiral groove liquid film seal under thermal–fluid–solid coupling

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Bo Yu ◽  
Muming Hao ◽  
Sun Xinhui ◽  
Zengli Wang ◽  
Liu Fuyu ◽  
...  
Keyword(s):  
Steady State ◽  
Liquid Film ◽  
Dynamic Characteristics ◽  
Dynamic Stiffness ◽  
Dynamic Performance ◽  
Analysis Model ◽  
Spiral Groove ◽  
Content Type ◽  
Sealing Performance ◽  
Stiffness And Damping

Purpose The purpose of this paper is to investigate the dynamic characteristics of spiral groove liquid film seal under the effect of thermal–fluid–solid coupling. Design/methodology/approach The dynamic analysis model of spiral groove liquid film seal under the effect of thermal–fluid–solid coupling was established by perturbation method. The steady-state and perturbation Reynolds equations were solved, and the steady-state sealing performance and dynamic characteristic coefficients of the liquid film were obtained. Findings Compared with the liquid film without coupling method, a divergent seal gap is formed between the seal rings under the effect of thermal–fluid–solid coupling, the minimum liquid film thickness decreases, the dynamic stiffness and damping coefficients of the liquid film are increased and the thermoelastic deformation of the end-face improves the dynamic performance of the liquid film seal. Originality/value The dynamic characteristics of the spiral groove liquid film seal under the effect of thermal–fluid–solid coupling are studied, which provides a theoretical reference for optimizing the dynamic performance of the non-contacting liquid film seal.

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].

The effects of joint clearance on the dynamics of the 3RRR planar parallel manipulator

Robotica ◽  
2016 ◽  
Vol 35 (6) ◽  
pp. 1223-1242 ◽  
Author(s):  
S. M. Varedi-Koulaei ◽  
H. M. Daniali ◽  
M. Farajtabar
Keyword(s):  
Parallel Manipulator ◽  
Dynamic Performance ◽  
Contact Forces ◽  
Force Model ◽  
Continuous Contact ◽  
Dissipative Term ◽  
Revolute Joints ◽  
Planar Parallel Manipulator ◽  
Performance Reduction ◽  
Design And Manufacturing

SUMMARYIn reality, clearances in the joints are inevitable due to tolerances, and defects arising from design and manufacturing. Therefore, poor dynamic performance, reduction in components component lifetimes and generation of undesirable vibrations result in impacts of mating parts in the clearance joint. In this study, the dynamic behavior of a planar mechanism with revolute joints, in the presence of clearances is investigated. A continuous contact force model, based on elastic Hertz theory together with a dissipative term, is used to evaluate the contact forces here. Moreover, using a contact model, the effects of working speed and clearance size on the dynamic characteristics of a planar mechanical system are analyzed and compared. Furthermore, numerical results for a 3RRR planar parallel manipulator with six revolute clearance joints are presented.

Modeling and Simulation of Aligning Process for Alignment Mechanism of Large Aircraft Component

2012 ◽  
Vol 160 ◽  
pp. 351-355
Author(s):  
Zheng Ying ◽  
Ying Lin Ke
Keyword(s):  
Dynamic Models ◽  
Dynamic Performance ◽  
Kinematic Model ◽  
Force Model ◽  
Continuous Contact ◽  
Contact Force Model ◽  
Aircraft Component ◽  
Alignment Mechanism ◽  
Kinematic Joint ◽  
Large Aircraft

The dynamic performance of alignment mechanism of large aircraft component is directly associated with the structure and clearance of spherical joints. To accurately evaluate this influence, kinematic and dynamic models of spherical joints are developed. Firstly, a kinematic model of spherical joints is established. Secondly, a dynamic model of spherical joints is derived from the kinematic model and continuous contact force model. Finally, simulations of alignment mechanism of large aircraft component are carried out for typical moving trajectories. The influences of moving trajectory on the dynamic performance of mechanism are analysed. The simulation results are also applicable to similar mechanism design, moving trajectory planning and kinematic joint wear forecasting.

Sign in / Sign up

Export Citation Format

Share Document