Study on Dynamic Performance of High Spot Open-Closed Gripper Mechanism in Printing Machine

2009 ◽  
Vol 419-420 ◽  
pp. 317-320
Author(s):  
Guo Dong Liu ◽  
Lin Lin Liu ◽  
Lei Zhang
Keyword(s):  
Contact Force ◽  
Relative Motion ◽  
Analytical Method ◽  
Structural Design ◽  
Mechanical Model ◽  
High Speed ◽  
Dynamic Performance ◽  
Force Contact ◽  
Printing Machine ◽  
Peak Value

The paper aims at attacking and noise problems of high spot open-closed gripper mechanism in printing machine in a high speed situation. The analytical method of dynamic performance is presented based on the relative motion, the absolute motion, and the mechanical model. And the analytical equations are established. Then, the dynamic performance of a practical mechanism from XINJI Company is analyzed by the proposed method. The drawbacks of dynamic performance are pointed out that the acceleration and apparent force had jumps in the running process. Finally, on the basis of existed problems, dynamic performance is modified by means of structural design of cam. The analytical results show that the angular acceleration’s peak value of improvement mechanism has been decreased by 62%. Besides, the modified mechanism also expresses an excellent dynamic performance as the flat curve of acceleration, apparent force, contact force and hinge force.

Analysis on Dynamic Performance of Hydrodynamic Tilting-Pad Gas Bearings Using Partial Derivative Method

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Yang Lihua ◽  
Qi Shemiao ◽  
Yu Lie
Keyword(s):  
Analytical Method ◽  
Gas Turbines ◽  
High Speed ◽  
Dynamic Performance ◽  
Gas Bearings ◽  
Dynamic Coefficients ◽  
Tilting Pad ◽  
Dynamic Performances ◽  
Perturbation Frequency ◽  
San Andres

Tilting-pad gas bearings are widely used in high-speed rotating machines due to their inherent stability characteristics. This paper advances the analytical method for prediction of the dynamic performances of tilting-pad gas bearings. The main advantage of the analytical method is that the complete set of dynamic coefficients of tilting-pad gas bearings can be obtained. The predictions show that the perturbation frequency has the strong effects on the dynamic coefficients of gas bearings. In general, at lower perturbation frequency, the equivalent direct stiffness coefficients increase with frequency, whereas equivalent direct damping coefficients dramatically reduce. For higher perturbation frequency, the dynamic coefficients are nearly independent of the frequency. Moreover, the equivalent dynamic coefficients of four-pad tilting-pad gas bearing obtained by the method in this paper are in good agreement with those obtained by Zhu and San Andres [(2007), “Rotordynamic Performance of Flexure Pivot Hydrostatic Gas Bearings for Oil-Free Turbomachinery,” ASME J. Eng. Gas Turbines Power, 129(4), pp. 1020–1027] in the published paper. The results validate the feasibility of the method presented in this paper in calculating the dynamic coefficients of gas-lubricated tilting-pad bearings.

Dynamic performance of a pantograph–catenary system with consideration of the contact surface

2016 ◽  
Vol 232 (1) ◽  
pp. 262-274 ◽  
Author(s):  
Dongli Song ◽  
Yanan Jiang ◽  
Weihua Zhang
Keyword(s):  
Contact Force ◽  
Wear Surface ◽  
Contact Surface ◽  
High Speed ◽  
Shape Parameter ◽  
Dynamic Performance ◽  
System Dynamic ◽  
Contact Wire ◽  
Catenary System ◽  
Contact Strip

The influence of contact surface upon the dynamic performance of a pantograph–catenary system is a question that has been highlighted by the increasing use of high speed railways. Using the mode-superposition method, we establish a pantograph–catenary-coupled dynamics model with consideration of the contact surface; we analyse the characteristics of the contact surface based on a large amount of measured data; and we determine the characteristic parameters according to their influence upon the system dynamic performance. The results show that the contact wire irregularity contains a periodic component formed by gravity and a random component formed by wear, local assembly errors, hardpoints and the like. Periodic and low-frequency random irregularities mainly lead to the increase in contact force amplitude at peak points with wavelengths submultiple of the tension length, span or dropper spacing. On the contrary, high-frequency random irregularity has a great influence upon the amplitude of all frequencies and is the main factor leading to the deterioration of the system dynamic performance. The contact strip wear surface achieves quadratic function fitting, and we propose two characteristic quantities of this surface, namely, shape parameter A, and wear depth B. The wear surface of contact strip enhances the periodic characteristics of pantograph–catenary system of each span, leading to the amplitude increase of the contact force in frequency with span submultiple wavelength. The bigger the absolute value of the shape parameter, the poorer the dynamic performance. According to the criteria of the contact force eigenvalues, we determine the threshold value of the contact strip shape parameter A, and the contact wire irregularity amplitude of each frequency. The threshold given in this paper can be used in the condition assessment of parts, and make judgements on whether a servicing is needed, which is part of the technologies for informationisation and intelligent high-speed train health management.

Application of Honeycomb Structure in Machine Tool Table

2011 ◽  
Vol 308-310 ◽  
pp. 1233-1237
Author(s):  
Dong Qiang Gao ◽  
Fei Zhang ◽  
Zhi Yun Mao ◽  
Huan Lin ◽  
Jiang Miao Yi
Keyword(s):  
Machine Tool ◽  
Structural Design ◽  
High Speed ◽  
Dynamic Performance ◽  
Inertial Force ◽  
Honeycomb Structure ◽  
Machining Accuracy ◽  
Aluminum Alloy Honeycomb ◽  
Better Than ◽  
Ansys Workbench

The aluminum alloy honeycomb structure used in the structural design of high-speed machine tool table to reduce the worktable’s quality, so that the inertial force generated from fast-moving reduced too. The new worktable and the original one both carried out static analysis and modal analysis by ANSYS Workbench respectively. From the result’s comparison, we can know that the new structure worktable’s static and dynamic performance are both better than the original one. The machine tool table’s machining accuracy has been raised.

scholarly journals Effect of Pantograph’s Main Structure on the Contact Quality in High-Speed Railway

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Jiangwen Wang ◽  
Guiming Mei
Keyword(s):  
Contact Force ◽  
Structural Design ◽  
High Speed ◽  
Electrical Energy ◽  
Dynamic Contact ◽  
Sine Series ◽  
High Speed Railway ◽  
Main Structure ◽  
Current Collection ◽  
Relative Coordinates

In general, the electrical energy is provided to the high-speed train through the pantograph-catenary sliding contact. The variation of the dynamic contact force is expected to be small enough to keep the good current collection quality and to extend the service life of the pantograph-catenary system. In this paper, the two tension wires of the catenary are discretized by the sine-series expansions, a multibody dynamics theory based on relative coordinates is adopted to describe the dynamic behavior of the pantograph, and the standard deviation (STD) of dynamic contact force is used as the indicator to evaluate the contact quality. The objective is to investigate how the variations of the pantograph’s main structure influence the contact quality, which may support the structural design and parameter optimization of the pantograph in high-speed railway.

Jumping Mechanism and Simulation of the Humanoid Robot

2011 ◽  
Vol 80-81 ◽  
pp. 1176-1179
Author(s):  
Yong Chen
Keyword(s):  
Structural Design ◽  
Mechanical Model ◽  
High Speed ◽  
Humanoid Robot ◽  
Video Camera ◽  
The Other ◽  
Arm Swing ◽  
High Speed Video ◽  
High Speed Video Camera ◽  
Jumping Robot

The jumping procedure of the human was captured with a high-speed video camera. The geometrical configurations and motion postures of the human during jumping were analyzed from the high-speed photographs. Based on the biological observation, the human jump was simplified and a mechanical model was put forward. The height and vertical velocity of COM of the human were analyzed. The angular velocity of the shoulder joint, hip joint, knee joint and ankle joint were shown in figure.It was shown that the arm swing was able to help increase the takeoff velocity. The results would provide some theoretical and practical references for biomimetic design for improving the reasonable motion of the jumping robot. This work may provide the basic theory in developing human jumping robot in structural design. Besides, it provides an important reference to study the other bionic robots.

A novel analytical calculation of magnetic field in the slotted air gap of spoke-type permanent-magnet machines using conformal mapping

2020 ◽  
pp. 1-15
Author(s):  
Jianqi Li ◽  
Yu Zhou ◽  
Jianying Li
Keyword(s):  
Magnetic Field ◽  
Conformal Mapping ◽  
Permanent Magnet ◽  
Flux Density ◽  
Analytical Method ◽  
Electromotive Force ◽  
Analytical Calculation ◽  
Air Gap ◽  
Permanent Magnet Machines ◽  
Peak Value

This paper presented a novel analytical method for calculating magnetic field in the slotted air gap of spoke-type permanent-magnet machines using conformal mapping. Firstly, flux density without slots and complex relative air-gap permeance of slotted air gap are derived from conformal transformation separately. Secondly, they are combined in order to obtain normalized flux density taking account into the slots effect. The finite element (FE) results confirmed the validity of the analytical method for predicting magnetic field and back electromotive force (BEMF) in the slotted air gap of spoke-type permanent-magnet machines. In comparison with FE result, the analytical solution yields higher peak value of cogging torque.

Dynamic Performance of High-Speed Electric Multiple Unit within Multi-Body System Simulation

2019 ◽  
Vol 12 (4) ◽  
pp. 339-349
Author(s):  
Junguo Wang ◽  
Daoping Gong ◽  
Rui Sun ◽  
Yongxiang Zhao
Keyword(s):  
High Speed ◽  
Rapid Development ◽  
Dynamic Performance ◽  
Body System ◽  
High Speed Railway ◽  
Evaluation Indexes ◽  
Actual Operation ◽  
Multiple Unit ◽  
The Stability ◽  
Multi Body

Background: With the rapid development of the high-speed railway, the dynamic performance such as running stability and safety of the high-speed train is increasingly important. This paper focuses on the dynamic performance of high-speed Electric Multiple Unit (EMU), especially the dynamic characteristics of the bogie frame and car body. Various patents have been discussed in this article. Objective: To develop the Multi-Body System (MBS) model of EMU, verify whether the dynamic performance meets the actual operation requirements, and provide some useful information for dynamics and structural design of the proposed EMU. Methods: According to the technical characteristics of a typical EMU, a MBS model is established via SIMPACK, and the measured data of China high-speed railway is taken as the excitation of track random irregularity. To test the dynamic performance of the EMU, including the stability and safety, some evaluation indexes such as wheel-axle lateral forces, wheel-axle lateral vertical forces, derailment coefficients and wheel unloading rates are also calculated and analyzed in detail. Results: The MBS model of EMU has better dynamic performance especially curving performance, and some evaluation indexes of the stability and safety have also reached China’s high-speed railway standards. Conclusion: The effectiveness of the proposed MBS model is verified, and the dynamic performance of the MBS model can meet the design requirements of high-speed EMU.

Dynamic Performance of HTS Maglev and Comparisons with Another Two Types of High-Speed Railway Vehicles

Cryogenics ◽  
2021 ◽  
pp. 103321
Author(s):  
Yuhang Yuan ◽  
Jipeng Li ◽  
Zigang Deng ◽  
Zhehao Liu ◽  
Dingding Wu ◽  
...  
Keyword(s):  
High Speed ◽  
Dynamic Performance ◽  
High Speed Railway ◽  
Railway Vehicles ◽  
Hts Maglev

A Fault Diagnosis Method for the Roller-Marks in Offset Printing Machine Based on Texture Recognition

2012 ◽  
Vol 262 ◽  
pp. 361-366
Author(s):  
Zhuo Fei Xu ◽  
Hai Yan Zhang ◽  
Ling Hui Ren
Keyword(s):  
Fault Diagnosis ◽  
High Speed ◽  
Solution Method ◽  
Offset Printing ◽  
Texture Recognition ◽  
Defect Image ◽  
Diagnosis Method ◽  
The Difference ◽  
Detecting Method ◽  
Printing Machine

Roller-mark is a common problem in offset printing and its solution method is important for printing. A new detecting method of texture analysis was given in this paper. In this study, printing image was acquired with high-speed CCD. Compared the difference between printing image and standard image, a defective image was obtained. Then the reason of roller-marks was given by the texture recognition of defect image. Finally, experiments were taken to prove the feasibility and effectiveness of this new method for the roller-marks diagnosis in the offset printing machine.

A Nonlinear Rail Vehicle Dynamics Computer Program SAMS/Rail: Part 1—Theory and Formulations

2009 ◽  
Author(s):  
Khaled E. Zaazaa ◽  
Brian Whitten ◽  
Brian Marquis ◽  
Erik Curtis ◽  
Magdy El-Sibaie ◽  
...  
Keyword(s):  
High Speed ◽  
Dynamic Performance ◽  
Three Dimensional ◽  
Contact Element ◽  
Contact Forces ◽  
Simulation Code ◽  
Vehicle Performance ◽  
Normal Contact ◽  
Advantages And Disadvantages ◽  
High Speed Trains

Accurate prediction of railroad vehicle performance requires detailed formulations of wheel-rail contact models. In the past, most dynamic simulation tools used an offline wheel-rail contact element based on look-up tables that are used by the main simulation solver. Nowadays, the use of an online nonlinear three-dimensional wheel-rail contact element is necessary in order to accurately predict the dynamic performance of high speed trains. Recently, the Federal Railroad Administration, Office of Research and Development has sponsored a project to develop a general multibody simulation code that uses an online nonlinear three-dimensional wheel-rail contact element to predict the contact forces between wheel and rail. In this paper, several nonlinear wheel-rail contact formulations are presented, each using the online three-dimensional approach. The methods presented are divided into two contact approaches. In the first Constraint Approach, the wheel is assumed to remain in contact with the rail. In this approach, the normal contact forces are determined by using the technique of Lagrange multipliers. In the second Elastic Approach, wheel/rail separation and penetration are allowed, and the normal contact forces are determined by using Hertz’s Theory. The advantages and disadvantages of each method are presented in this paper. In addition, this paper discusses future developments and improvements for the multibody system code. Some of these improvements are currently being implemented by the University of Illinois at Chicago (UIC). In the accompanying “Part 2” and “Part 3” to this paper, numerical examples are presented in order to demonstrate the results obtained from this research.

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