scholarly journals Study on Rigid-Flexible Coupling Dynamic Model of Globoid Cam Indexing Mechanism with Six Degrees of Freedom

2016 ◽  
Author(s):  
Zhenghao Ge ◽  
Chen Liang ◽  
Chengping Li
Keyword(s):  
Dynamic Model ◽  
Degrees Of Freedom ◽  
Flexible Coupling ◽  
Six Degrees Of Freedom ◽  
Coupling Dynamic ◽  
Indexing Mechanism ◽  
Coupling Dynamic Model

Rigid–flexible coupling dynamics analysis with joint clearance for a 5-DOF hybrid polishing robot

Robotica ◽  
2021 ◽  
pp. 1-21
Author(s):  
Feng Guo ◽  
Gang Cheng ◽  
Shilin Wang ◽  
Jun Li
Keyword(s):  
Dynamic Model ◽  
Parallel Manipulator ◽  
Dynamic Properties ◽  
Dynamic Performance ◽  
Joint Clearance ◽  
Motion Error ◽  
Flexible Coupling ◽  
Coupling Dynamic ◽  
Equivalent Load ◽  
Coupling Dynamic Model

SUMMARY Considering the polishing requirements for high-precision aspherical optical mirrors, a hybrid polishing robot composed of a serial–parallel manipulator and a dual rotor grinding system is proposed. Firstly, based on the kinematics of serial components, the equivalent load model for the parallel manipulator is established. Then, the elastodynamic model of kinematic branched-chains of the parallel manipulator is established by using the spatial beam element, and the rigid–flexible coupling dynamic model of the polishing robot is obtained with Kineto-elasto dynamics theory. Further, considering the dynamic properties of the joint clearance, the rigid–flexible coupling dynamic model with the joint clearance for the polishing robot is established. Finally, the equivalent load distribution of the parallel manipulator is analyzed, and the effect of the branched-chain elasticity and joint clearance on the motion error of the polishing robot is studied. This article provides a theoretical basis for improving the motion accuracy and dynamic performance of the hybrid polishing robot.

Vibration analysis of a flexible gearbox system considering a local fault in the outer ring of the supported ball bearing

2020 ◽  
pp. 107754632093688
Author(s):  
Jing Liu ◽  
Lei Yuan
Keyword(s):  
Dynamic Model ◽  
Transmission System ◽  
Gear Transmission ◽  
Ball Bearings ◽  
Transmission Characteristics ◽  
Flexible Coupling ◽  
Flexible Shaft ◽  
Gear Transmission System ◽  
Coupling Dynamic ◽  
Coupling Dynamic Model

Ball bearings are key components in the gear transmission system. Supported ball bearings have great influences on the vibrations of the gear transmission system, especially the presence of the local faults. Although some reported works formulated the local fault in the supported bearings of the gear transmission system, the box and shaft were considered as rigid bodies. To overcome this problem, a rigid-flexible coupling dynamic model for a flexible gearbox with the supported ball bearings is developed, which cannot be described by the previous multibody models. The local fault in the supported bearing is described by a time-varying impact force model with a half-sine profile. The bearing clearance, flexible shaft, and box are considered in the rigid-flexible coupling dynamic model. The flexible shaft and box are formulated by a finite element method. The damping and contact stiffness in the bearings and gears are obtained by the previous methods in the listed works. The frictions between the mating components are formulated by the Coulomb friction model. An experimental study is applied to validate the rigid-flexible coupling dynamic model. The effects of the faults on the vibration transmission characteristics are investigated. The results provide that the local fault in the supported bearings will greatly affect the vibrations of the gearbox system. Moreover, it depicts that the vibration collection point for the defective bearings should be located at the same side to obtain better singles. This work can provide a more reasonable method for understanding the vibration transmission characteristics of the gearbox system with the local faults in the supported bearings than the reported multibody models.

Dynamic Simulation Analysis of Shipborne Missile Launching under High-Wave-Level Environment

2012 ◽  
Vol 569 ◽  
pp. 380-385
Author(s):  
Zhou Zhong ◽  
Yi Jiang ◽  
Yong Yuan Li ◽  
Chong Zhang
Keyword(s):  
Dynamic Response ◽  
Dynamic Model ◽  
Dynamic Simulation ◽  
Simulation Analysis ◽  
Simulation Method ◽  
Flexible Coupling ◽  
High Wave ◽  
Model And Simulation ◽  
Coupling Dynamic ◽  
Coupling Dynamic Model

In order to study the dynamic response of shipborne missile vertical launching under high-wave-level environment, the rigid-flexible coupling dynamic model of launching system was built by ways of virtual prototype technology. According to simulations for different launching conditions, missile attitude parameters were acquired, and interference of various parts was analyzed. The result shows that the dynamic model and simulation method proposed in this paper are effective and practicable.

scholarly journals Thermos-Solid-Gas Coupling Dynamic Model and Numerical Simulation of Coal Containing Gas

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Xiao Fukun ◽  
Meng Xin ◽  
Li Lianchong ◽  
Liu Jianfeng ◽  
Liu Gang ◽  
...  
Keyword(s):  
Principal Stress ◽  
Dynamic Model ◽  
Gas Flow ◽  
Flow Behavior ◽  
Coupling Model ◽  
Gas Pressure ◽  
Permeability Model ◽  
Gas Seepage ◽  
Coupling Dynamic ◽  
Coupling Dynamic Model

Based on gas seepage characteristics and the basic thermo-solid-gas coupling theory, the porosity model and the dynamic permeability model of coal body containing gas were derived. Based on the relationship between gas pressure, principal stress and temperature, and gas seepage, the thermo-solid-gas coupling dynamic model was established. Initial values and boundary conditions for the model were determined. Numerical simulations using this model were done to predict the gas flow behavior of a gassy coal sample. By using the thermo-solid-gas coupling model, the gas pressure, temperature, and principal stress influence, the change law of the pressure field, displacement field, stress field, temperature field, and permeability were numerically simulated. Research results show the following: (1) Gas pressure and displacement from the top to the end of the model gradually reduce, and stress from the top to the end gradually increases. The average permeability of the Y Z section of the model tends to decrease with the rise of the gas pressure, and the decrease amplitude slows down from the top of the model to the bottom. (2) When the principal stress and temperature are constant, the permeability decreases first and then flattens with the gas pressure. The permeability increases with the decrease of temperature while the gas pressure and principal stress remain unchanged.

scholarly journals A new vertical dynamic model for railway vehicle with passenger-train-track coupling vibration

2019 ◽  
Vol 234 (1) ◽  
pp. 134-146
Author(s):  
Yuewei Yu ◽  
Leilei Zhao ◽  
Changcheng Zhou
Keyword(s):  
Dynamic Model ◽  
Railway Vehicle ◽  
Train Track ◽  
Passenger Train ◽  
Railway Vehicles ◽  
Vertical Coupling ◽  
Track System ◽  
Coupling Dynamic ◽  
Train System ◽  
Coupling Dynamic Model

In order to further reveal the vertical random vibration characteristics of railway vehicles, using the system engineering method, taking the passenger, the train system, and the track system (ballast track) as a unified whole, a passenger-train-track vertical coupling dynamic model is established, and the vibration differential equations of the model are derived. In the model, passengers are regarded as a single-degree-of-freedom system attached to the bottom of the carriage, the train system is represented as a 10-degree-of-freedom multi-rigid body model, the track system is regarded as the infinite long Euler beam model with three layers of continuous elastic point support, and the Hertz nonlinear elastic contact theory is applied to the wheel and rail coupling relationship. Based on this, the time-domain numerical solution of the passenger-train-track vertical coupling dynamic model is given by using Newmark- β implicit integration algorithm, and the correctness of the model is verified by the real vehicle test. This study can provide some theoretical basis for the design of railway vehicles and provide fundamentals for the coordinated control and system optimization of railway vehicle ride comfort.

Sign in / Sign up

Export Citation Format

Share Document