Optimal Design of the Path of Chain Link Systems

1990 ◽  
Author(s):  
J.-P. Peng ◽  
M. Carpino
Keyword(s):  
Optimal Design ◽  
Dynamic Analysis ◽  
Dynamic Model ◽  
High Speed ◽  
Position Error ◽  
Dynamic Effects ◽  
Low Speed ◽  
Chain Link ◽  
A Chain ◽  
General Method

Abstract A general method for the design of the optimal chain path for a chain link system is presented. The dynamics of a chain link system are affected by both the kinematic effects of finite sized links and dynamic effects. Both of these effects have been incorporated into a dynamic model for arbitrary chain paths. This model is then used to determine chain paths which have been optimized for minimum position error and speed variation. Results of the dynamic analysis are presented for both low speed and high speed operations. An example of an optimized chain path for an oval configuration operating at low speed is also presented.

Optimal Design of the Path of Chain Link Systems

1993 ◽  
Vol 115 (4) ◽  
pp. 793-799 ◽  
Author(s):  
J.-P. Peng ◽  
M. Carpino
Keyword(s):  
Optimal Design ◽  
Dynamic Model ◽  
Constant Velocity ◽  
Small Amplitude ◽  
Optimal Path ◽  
Dynamic Effects ◽  
Chain System ◽  
Chain Link ◽  
Direct Perturbation ◽  
General Method

A general method for the design of the optimal path for a constant velocity chain system is presented. Both the dynamic effects and the kinematic effects of finite sized links have been incorporated into a dynamic model for arbitrary chain paths. A direct perturbation solution is developed for small amplitude oscillations. This model is then used to optimize chain paths for minimum position error and speed variation. An example of an optimized chain path for an oval configuration operating at low speed is presented.

scholarly journals Multi-body Dynamic Modelling and Error Analysis of Planar Flexible Multilink Mechanism Considering Clearance and Thermal-mechanical Coupling Effect of the Crankshaft-bearing Structure

2021 ◽  
Author(s):  
Hongfan Long ◽  
Zhao Han ◽  
Shuyun Jiang ◽  
Enlai Zheng ◽  
Yongnian Zhang ◽  
...  
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Coupling Effect ◽  
Dynamic Modelling ◽  
Variable Stiffness ◽  
Position Error ◽  
Mechanical Coupling ◽  
Spindle Bearing ◽  
Bearing Structure ◽  
Bearing System

Abstract In order to study the dynamic position accuracy of bottom dead point (BDP) for multilink high-speed precision presses (MHSPPs), it’s essential to develop a dynamic model of planar multilink mechanism with clearance and spindle-bearing structure. Traditional models always neglect the effect of thermal characteristics of spindle-bearing structure, which reduces the prediction accuracy of dynamic model for multilink transmission mechanisms. To overcome the shortcomings of the previous models, a thermal network model (TNM) of the crankshaft-bearing system is established firstly considering the effects of thermal contact resistance and variable stiffness of bearing concerning the temperature rise. Then, dynamic model of the crankshaft-bearing system is built through the finite element method, which includes rigid disk, Timoshenko beam and quasi-statics model of ACBB. On this basis, an improved dynamic model of planar flexible multilink mechanism with clearance considering the thermal-mechanical coupling effect of the crankshaft-bearing structure is developed and the corresponding dynamic error dimension chain between slider and crankshaft is constructed in this work. Compared to the simulation from traditional models, the simulated slider’s BPD position error from the improved model agrees better with experimental data, which verifies the correctness of the proposed model. It’s demonstrated that the punching force and thermally induced variable stiffness of bearing lead to a significant increase of slider’s BDP position error, which reduces the machining precision of MHSPP. Furthermore, the influence of crankshaft speed, contact angle of bearing and clearance size on the slider’s BDP position error is also investigated.

A Dynamic Analysis of the Oscillations in a Chain Drive

1999 ◽  
Vol 123 (3) ◽  
pp. 395-401 ◽  
Author(s):  
I. Troedsson ◽  
L. Vedmar
Keyword(s):  
Dynamic Analysis ◽  
Equilibrium Condition ◽  
High Speed ◽  
Transverse Oscillation ◽  
Chain Drive ◽  
Equilibrium Equations ◽  
Gravitational Forces ◽  
Geometric Conditions ◽  
A Chain ◽  
Inertia Forces

A model is presented in which the oscillations, and the forces thus produced, in a chain drive, working at moderate and high speed, can be calculated. Since the outer system affects the result it has been necessary to include this in the model. The mass of the chain is included in the model and both the gravitational forces and the inertia forces in the chain are taken into account. The elasticity in the links is included. The sprockets are connected by two spans, both of which have to be included in the model to fulfill the equilibrium equations for the rollers in contact with the sprockets. The position of the chain is given by the geometric conditions as well as the equilibrium condition. On the slack side a chain tensioner is used to reduce the transverse oscillation, which occur at higher speeds.

scholarly journals Dynamic Analysis of Historic Railway Bridges in Poland in the Context of Adjusting Them to Pendolino Trains

2015 ◽  
Vol 20 (2) ◽  
pp. 283-297 ◽  
Author(s):  
K. Grębowski ◽  
M. Zielińska
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Model ◽  
High Speed ◽  
Experimental Studies ◽  
Rolling Stock ◽  
Railway Bridge ◽  
High Speed Train ◽  
Railway Bridges ◽  
High Speed Trains ◽  
Identical Type

Abstract The article presents the dynamic analysis of the historic railway bridge in Tczew as an example of the usefulness of such type of bridge for high-speed trains. The model of the bridge and the simulation of rolling stock passage was performed in SOFISTIK program. The scope of work includes experimental studies, the solution of the problem concerning the correct solution features of the dynamic model which takes into account the dependencies between the bridge, track and rolling - stock (RBT). The verification of the model was performed by comparing the results obtained on site during the passage of ET-22 locomotive and twenty (20) open goods wagons with the results obtained in the program for the identical type of rolling stock used to the simulation Pendolino train. Then, after the verification, the simulation of high-speed train passage was performed. The speed of the train passage varied from 150 [km/h] to the max. possible speed of 250 [km/h] which PENDOLINO train, approved for the simulation, may reach. Under the analysis of obtained results it was possible to define the conditions for adjusting the historic bridge to high-speed train passage.

scholarly journals Nonlinear friction dynamic modeling and performance analysis of flexible parallel robot

2020 ◽  
Vol 17 (6) ◽  
pp. 172988142097251
Author(s):  
Lei Zhao ◽  
Xin-hua Zhao ◽  
Bin Li ◽  
Yu-wei Yang ◽  
Liang Liu
Keyword(s):  
Dynamic Model ◽  
Dynamic Modeling ◽  
High Speed ◽  
Parallel Robot ◽  
Friction Model ◽  
Parameters Identification ◽  
Common Method ◽  
Nonlinear Friction ◽  
Low Speed ◽  
The Stability

The article presents a friction dynamic modeling method for a flexible parallel robot considering the characteristics of nonlinear friction. An approximate friction model which is proposed by Kostic et al. is applied to establish the dynamic model with Lagrange method. Parameters identification is completed by least square method, and the tracking accuracy and the stability of the robot are systematically analyzed before and after dynamic compensation at different speeds. Its position error of the robot after compensation is only 0.98 mm at low speed. The accuracy is improved 10 times than that before compensation. In addition, the peak velocity errors are 3.97 mm·s−1 and 1.49 mm·s−1 at high and low speed, respectively, which are reduced 2.5 times than that before compensation. The experimental data also indicate that velocity tracking curve has no obvious peak error compared with the common method based on Coulomb and viscous friction model. The curve is much smoother with proposed model, and the motion stability of robot at high speed has been greatly improved. The proposed method just needs the robot to collect some positions before path tracing, and the parameters identification of dynamic model can be completed quickly. The compensation effect is much more better than common method. So the proposed method can be extended to complete the dynamic identification for complex robot with more joints. It is helpful to further improve the stability and the accuracy at high speed.

scholarly journals Analysis of vibration status of power generating unit reducers

2019 ◽  
Vol 2019 (4) ◽  
pp. 96-106
Author(s):  
Вадим Пшеничный ◽  
Vadim Pshenichnyy ◽  
Алексей Сальников ◽  
Alexey Salnikov
Keyword(s):  
Dynamic Analysis ◽  
High Speed ◽  
Operation Mode ◽  
Technical Condition ◽  
Vibration Measurement ◽  
Structural Elements ◽  
Bending Vibrations ◽  
Dynamic Interactions ◽  
Low Speed ◽  
Power Generating Unit

The reducers of power units are being studied. Dynamic analysis of the basic structural elements of reducers has been carried out. There have been found the possible causes of the increased wear of surfaces of toothed linkages of herringbone transfer. There are given the results of studying dynamic interactions by vibration characteristics of measuring the vibration level in bearing blocks and elements of reducers of power units at their technological operation mode. To analyze the frequency interaction of structural elements of the studied reducers there were used the results of modal analysis of earlier conducted researches of the reducer power unit. It has been stated that for conducting vibrodiagnostic control the third class machines were chosen due to their powerful primary engines, and other machines with rotating masses mounted on massive foundations, rigid in the direction of vibration measurement. Phase angles of high-speed and low-speed shaft wheels for the purpose of defining a corner of phase shift (torsional fluctuations of shaft wheels) at reverse frequencies and frequencies of toothed linkage have been studied. In terms of dynamic analysis it allows to trace trajectories of linkages in toothed couples of divided wheels of herringbone gearing. The diagrams of gear trajectories are illustrated for bending vibrations of the shaft-wheels. The research results confirming the nonlinear relationship between the level of axial vibrations and the displacement angle of instantaneous phase angle are presented. It has been recommended to reduce the level of axial vibration transmitted from the coupling to 0.1–0.2 mm/s for eliminating uneven wear in the chevron gear; carry out structural improvements to the high-speed and low-speed shaft-wheels with increasing rigidity between the elements of chevron transmission; operate gearboxes within critical values; timely monitor the technical condition of gearboxes.

scholarly journals Coupled dynamic model and vibration responses characteristic of a motor-driven flexible manipulator system

2015 ◽  
Vol 6 (2) ◽  
pp. 235-244 ◽  
Author(s):  
Y. F. Liu ◽  
W. Li ◽  
X. F. Yang ◽  
Y. Q. Wang ◽  
M. B. Fan ◽  
...  
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Model ◽  
High Speed ◽  
Dynamic Effect ◽  
Structure Design ◽  
Integrated System ◽  
Flexible Manipulator ◽  
Effect Mechanism ◽  
Motion Optimization ◽  
Vibration Responses

Abstract. Motor-driven flexible manipulator systems (MDFMSs) are widely used in industry robot fields. During the dynamic modeling, the separate investigation method which neglects the dynamic behavior of the driving motor will cause an error in the dynamic analysis of the flexible manipulator, especially with high-speed operations. This paper proposes a coupled dynamic model of the MDFMS in which the driving motor and flexible manipulator are considered as an integrated system, which can clearly reflect the influence of the dynamic effect of the driving motor. Based on the proposed dynamic model, the vibration responses of the flexible manipulator under different velocities, accelerations and structure parameters, as well as the effect mechanism of the driving motor on the vibration responses, are investigated. The results obtained in this paper contribute to the structure design, motion optimization and dynamic analysis of flexible manipulators.

Crack divergence phenomena in tempered glass

2020 ◽  
Vol 13 (3) ◽  
pp. 115-129
Author(s):  
Shin’ichi Aratani
Keyword(s):  
Optimal Design ◽  
High Speed ◽  
Glass Plate ◽  
Acute Angle ◽  
Divergence Angle ◽  
High Speed Photography ◽  
Tempered Glass ◽  
Thick Glass

High speed photography using the Cranz-Schardin camera was performed to study the crack divergence and divergence angle in thermally tempered glass. A tempered 3.5 mm thick glass plate was used as a specimen. It was shown that two types of bifurcation and branching existed as the crack divergence. The divergence angle was smaller than the value calculated from the principle of optimal design and showed an acute angle.

Do You Name Speedy Objects Faster Than Slow Objects: SPEEDED NAMING OR NAMING SPEED? THE AUTOMATIC EFFECT OF OBJECT SPEED ON PERFORMANCE

2018 ◽  
Author(s):  
Moshe Shay Ben-Haim ◽  
Eran Chajut ◽  
Ran Hassin ◽  
Daniel Algom
Keyword(s):  
High Speed ◽  
Mental Representations ◽  
Reading Aloud ◽  
Naming Task ◽  
Naming Speed ◽  
Low Speed ◽  
Everyday Objects ◽  
Pictures And Words

we test the hypothesis that naming an object depicted in a picture, and reading aloud an object’s name, are affected by the object’s speed. We contend that the mental representations of everyday objects and situations include their speed, and that the latter influences behavior in instantaneous and systematic ways. An important corollary is that high-speed objects are named faster than low-speed objects despite the fact that object speed is irrelevant to the naming task at hand. The results of a series of 7 studies with pictures and words support these predictions.

Dynamic model for high-speed rotors based on their experimental characterization

2017 ◽  
Vol 2 (4) ◽  
pp. 25
Author(s):  
L. A. Montoya ◽  
E. E. Rodríguez ◽  
H. J. Zúñiga ◽  
I. Mejía
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Experimental Characterization ◽  
Rotating Systems ◽  
Computing Performance ◽  
The Impact ◽  
Stiffness Distribution ◽  
Good Agreement

Rotating systems components such as rotors, have dynamic characteristics that are of great importance to understand because they may cause failure of turbomachinery. Therefore, it is required to study a dynamic model to predict some vibration characteristics, in this case, the natural frequencies and mode shapes (both of free vibration) of a centrifugal compressor shaft. The peculiarity of the dynamic model proposed is that using frequency and displacements values obtained experimentally, it is possible to calculate the mass and stiffness distribution of the shaft, and then use these values to estimate the theoretical modal parameters. The natural frequencies and mode shapes of the shaft were obtained with experimental modal analysis by using the impact test. The results predicted by the model are in good agreement with the experimental test. The model is also flexible with other geometries and has a great time and computing performance, which can be evaluated with respect to other commercial software in the future.

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