Study on the Section's Extreme Position of Roadheader's Cutting Arm in Coal Mine Laneway

2011 ◽  
Vol 88-89 ◽  
pp. 5-9 ◽  
Author(s):  
Jing Mu ◽  
Yi Bo Du ◽  
Rui Li ◽  
Jie Tian ◽  
Miao Wu
Keyword(s):  
Coal Mine ◽  
Spatial Modeling ◽  
Control Method ◽  
Three Dimensional ◽  
Research Direction ◽  
Boundary Values ◽  
Modeling And Analysis ◽  
Cutting Head ◽  
Section Shape ◽  
Important Research Direction

Directional excavation technology in the coal mine laneway is the important research direction of integrated excavation project. This paper studies the changes of cutting section shape and boundary values caused by the swing of boom-type roadheader's cutting arm ​​to calculate the maximum values of compensable pose deviation when cutting, as the research basis for the accuracy analysis of boom-type roadheader's directional excavation. This paper gives the calculation method of cutting arm control, spatial modeling and analysis of cutting head position changes caused by cutting arm in thought of the three-dimensional analytic geometry, and also gives verification in the way of Matlab graphics simulation. At last, a control method to compensate section boundary by cutting arm is put forward.

scholarly journals Height Estimation of Target Objects Based on Structured Light

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Wei Liu ◽  
Yongsheng Zhao
Keyword(s):  
Simple Structure ◽  
Structured Light ◽  
Three Dimensional ◽  
Research Direction ◽  
Target Object ◽  
Height Estimation ◽  
Word Structure ◽  
Dimensional Reconstruction ◽  
Important Research Direction ◽  
Structure Light

The height estimation of the target object is an important research direction in the field of computer vision. The three-dimensional reconstruction of structured light has the characteristics of high precision, noncontact, and simple structure and is widely used in military simulation and cultural heritage protection. In this paper, the height of the target object is estimated by using the word structure light. According to the height dictionary, the height under the offset is estimated by the movement of the structured light to the object. In addition, by effectively preprocessing the captured structured light images, such as expansion, seeking skeleton, and other operations, the flexibility of estimating the height of different objects by structured light is increased, and the height of the target object can be estimated more accurately.

Based on Pro/Toolkit Parametric Design of the Longitudinal Roadheader Cutting Head

2012 ◽  
Vol 619 ◽  
pp. 195-198
Author(s):  
Li Juan Zhao ◽  
Zheng Jun Wu ◽  
Zhen Tian
Keyword(s):  
Coal Mine ◽  
Parametric Design ◽  
Three Dimensional ◽  
Coal Industry ◽  
Special Equipment ◽  
Second Development ◽  
Analysis And Design ◽  
Cutting Head ◽  
Development Tools ◽  
Parametric Cad

Through to the analysis and design of cutting head, three-dimensional molding software Pro/E as the foundation, and vc++6.0 as a Second development tools, as well as achieved automatic update and assembly of the parts of cutting head, and shorten the design cycle.The environment of achieving cutting head in parametric CAD,the coal industry special equipment for coal mine normalized components parametric design has the great significance,for parametric designed of other products, provided valuable experience, great value.

Study on the Shovel and Support Bracket’s Compensation for Vertical Pose’s Deviation of Roadheader

2011 ◽  
Vol 328-330 ◽  
pp. 1832-1836 ◽  
Author(s):  
Jing Mu ◽  
Miao Wu
Keyword(s):  
Body Weight ◽  
Coal Mine ◽  
Research Direction ◽  
Accuracy Analysis ◽  
Important Research ◽  
Extreme Position ◽  
Vertical Angle ◽  
Basic Body ◽  
Control Application ◽  
Important Research Direction

Automatic directional excavation technology in the coal mine laneway is the important research direction of integrated excavation project. Shovel and support bracket are the most key parts for keeping roadheader body stable in excavation. This paper studies the control ability and extreme position of boom-type roadheader’s shovel and support bracket, to calculate the adjustable vertical angles rang which is realized by shovel and support bracket, expanding roadheader’s automatic compensating excavation ability, meanwhile ensuring body stable. Vertical angle is one of the four kinds of basic body pose deviation parameters. This study is the research basis for the accuracy analysis of boom-type roadheader’s directional excavation. Because the depth that shovel and support brackets’ tip compress into laneway ground, is mainly determined by laneway ground hardness and body weight, and can’t be calculate accurately, paper’s end gives feedback control application of shovel and support bracket according to laneway conditions.

Four-point dynamic leveling method for drilling platform application

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Dongmin Li ◽  
Guofang Ma ◽  
Jia Li
Keyword(s):  
Coal Mine ◽  
Control Method ◽  
Dynamic Performance ◽  
Three Dimensional ◽  
Underground Coal Mine ◽  
Content Type ◽  
Displacement Sensors ◽  
Leveling Control ◽  
Combined Sensor ◽  
Support Rod

Purpose It is essential to level the drilling platform across which a drilling robot travels in a slant underground coal mine tunnel to ensure smooth operation of the drill rod. However, existing leveling methods do not provide dynamic performance under the drilling conditions of the underground coal mine. A four-point dynamic leveling algorithm is presented in this paper based on the platform attitude and support rod displacement (DLAAD). An experimental drilling robot demonstrates its dynamic leveling capability and ability to ensure smooth drill rod operations. Design/methodology/approach The attitude coordinate of the drilling robot is established according to its structure. A six-axis combined sensor is adopted to detect the platform attitude, thus revealing the three-axis Euler angles. The support rod displacement values are continuously detected by laser displacement sensors to obtain the displacement increment of each support rod as needed. The drilling robot is leveled according to the current support rod displacement and three-dimensional (3 D) attitude detected by the six-axis combined sensor dynamically. Findings Experimental results indicate that the DLAAD algorithm is correct and effectively levels the drilling platform dynamically. It can thus provide essential support in resolving drill rod sticking problems during actual underground coal mine drilling operations. Practical implications The DLAAD algorithm supports smooth drill rod operations in underground coal mines, which greatly enhances safety, reduces power consumption, and minimizes cost. The approach proposed here thus represents considerable benefits in terms of coal mine production and shows notable potential for application in similar fields. Originality/value The novel DLAAD algorithm and leveling control method are the key contributions of this work, they provide dynamical 3 D leveling and help to resolve drill rod sticking problems.

SEISMIC VULNERABILITY ASSESSMENT FOR SAN FRANCISCO TEMPLE IN MORELIA, MEXICO

2019 ◽  
Vol 3 (Special Issue on First SACEE'19) ◽  
pp. 207-2016
Author(s):  
Guillermo Martinez ◽  
David Castillo ◽  
José Jara ◽  
Bertha Olmos
Keyword(s):  
San Francisco ◽  
Seismic Vulnerability ◽  
Seismic Analysis ◽  
Three Dimensional ◽  
Middle Part ◽  
Seismic Demands ◽  
Modeling And Analysis ◽  
Seismic Records ◽  
Cracking Pattern ◽  
The Temple

This paper presents a first approximation of the seismic vulnerability of a sixteenth century building which is part of the historical center of Morelia, Mexico. The city was declared World Heritage by United Nations Educational, Scientific and Cultural Organization in 1991. The modeling and analysis of the building was carried out using a three-dimensional elastic tetrahedral finite elements model which was subjected to probabilistic seismic demands with recurrences of 500 yrs and 1000 yrs in addition to real seismic records. The model was able to correctly identify cracking pattern in different parts of the temple due to gravitational forces. High seismic vulnerability of the arched window and the walls of the middle part of the bell tower of the temple was indicated by the seismic analysis of the model.

Disorganization of a hole tone feedback loop by an axisymmetric obstacle on a downstream end plate

2014 ◽  
Vol 757 ◽  
pp. 908-942 ◽  
Author(s):  
K. Matsuura ◽  
M. Nakano
Keyword(s):  
Nozzle Exit ◽  
Passive Control ◽  
Control Method ◽  
Three Dimensional ◽  
Acoustic Power ◽  
Shear Layers ◽  
Mean Velocity ◽  
End Plate ◽  
Air Jet ◽  
Practical Engineering

AbstractThis study investigates the suppression of the sound produced when a jet, issued from a circular nozzle or hole in a plate, goes through a similar hole in a second plate. The sound, known as a hole tone, is encountered in many practical engineering situations. The mean velocity of the air jet $\def \xmlpi #1{}\def \mathsfbi #1{\boldsymbol {\mathsf {#1}}}\let \le =\leqslant \let \leq =\leqslant \let \ge =\geqslant \let \geq =\geqslant \def \Pr {\mathit {Pr}}\def \Fr {\mathit {Fr}}\def \Rey {\mathit {Re}}u_0$ was $6\text {--}12\ \mathrm{m}\ {\mathrm{s}}^{-1}$. The nozzle and the end plate hole both had a diameter of 51 mm, and the impingement length $L_{im}$ between the nozzle and the end plate was 50–90 mm. We propose a novel passive control method of suppressing the tone with an axisymmetric obstacle on the end plate. We find that the effect of the obstacle is well described by the combination ($W/L_{im}$, $h$) where $W$ is the distance from the edge of the end plate hole to the inner wall of the obstacle, and $h$ is the obstacle height. The tone is suppressed when backflows from the obstacle affect the jet shear layers near the nozzle exit. We do a direct sound computation for a typical case where the tone is successfully suppressed. Axisymmetric uniformity observed in the uncontrolled case is broken almost completely in the controlled case. The destruction is maintained by the process in which three-dimensional vortices in the jet shear layers convect downstream, interact with the obstacle and recursively disturb the jet flow from the nozzle exit. While regions near the edge of the end plate hole are responsible for producing the sound in the controlled case as well as in the uncontrolled case, acoustic power in the controlled case is much lower than in the uncontrolled case because of the disorganized state.

scholarly journals 2D and 3D Palmprint and Palm Vein Recognition Based on Neural Architecture Search

2021 ◽  
Author(s):  
Wei Jia ◽  
Wei Xia ◽  
Yang Zhao ◽  
Hai Min ◽  
Yan-Xiang Chen
Keyword(s):  
Deep Learning ◽  
Recognition Performance ◽  
Research Direction ◽  
Palmprint Recognition ◽  
Neural Architecture ◽  
Development Direction ◽  
Vein Recognition ◽  
Palm Vein ◽  
2D And 3D ◽  
Important Research Direction

AbstractPalmprint recognition and palm vein recognition are two emerging biometrics technologies. In the past two decades, many traditional methods have been proposed for palmprint recognition and palm vein recognition and have achieved impressive results. In recent years, in the field of artificial intelligence, deep learning has gradually become the mainstream recognition technology because of its excellent recognition performance. Some researchers have tried to use convolutional neural networks (CNNs) for palmprint recognition and palm vein recognition. However, the architectures of these CNNs have mostly been developed manually by human experts, which is a time-consuming and error-prone process. In order to overcome some shortcomings of manually designed CNN, neural architecture search (NAS) technology has become an important research direction of deep learning. The significance of NAS is to solve the deep learning model’s parameter adjustment problem, which is a cross-study combining optimization and machine learning. NAS technology represents the future development direction of deep learning. However, up to now, NAS technology has not been well studied for palmprint recognition and palm vein recognition. In this paper, in order to investigate the problem of NAS-based 2D and 3D palmprint recognition and palm vein recognition in-depth, we conduct a performance evaluation of twenty representative NAS methods on five 2D palmprint databases, two palm vein databases, and one 3D palmprint database. Experimental results show that some NAS methods can achieve promising recognition results. Remarkably, among different evaluated NAS methods, ProxylessNAS achieves the best recognition performance.

Towards effective link prediction: A hybrid similarity model

2020 ◽  
pp. 1-14
Author(s):  
Longjie Li ◽  
Lu Wang ◽  
Hongsheng Luo ◽  
Xiaoyun Chen
Keyword(s):  
Link Prediction ◽  
Structural Similarity ◽  
Research Direction ◽  
Structural Features ◽  
Proposed Model ◽  
Similarity Model ◽  
Weight Calculation ◽  
Stable Performance ◽  
Grey Relation ◽  
Important Research Direction

Link prediction is an important research direction in complex network analysis and has drawn increasing attention from researchers in various fields. So far, a plethora of structural similarity-based methods have been proposed to solve the link prediction problem. To achieve stable performance on different networks, this paper proposes a hybrid similarity model to conduct link prediction. In the proposed model, the Grey Relation Analysis (GRA) approach is employed to integrate four carefully selected similarity indexes, which are designed according to different structural features. In addition, to adaptively estimate the weight for each index based on the observed network structures, a new weight calculation method is presented by considering the distribution of similarity scores. Due to taking separate similarity indexes into account, the proposed method is applicable to multiple different types of network. Experimental results show that the proposed method outperforms other prediction methods in terms of accuracy and stableness on 10 benchmark networks.

Preparation and Properties of Alginate Fibre

2011 ◽  
Vol 335-336 ◽  
pp. 419-422 ◽  
Author(s):  
Yuan Lian ◽  
Jian Yi Wu ◽  
Da Peng Zhou ◽  
Hong Mei Wang ◽  
Dian Wu Huang ◽  
...  
Keyword(s):  
Research Direction ◽  
Biological Properties ◽  
Wet Spinning ◽  
Structure And Properties ◽  
Important Research ◽  
Preparation Technology ◽  
Thermal Gravimetric Analyzer ◽  
Infrared Spectrometer ◽  
Medical Materials ◽  
Important Research Direction

Alginate fibre has attracted great attention in the area of biological medical materials due to its unique biological properties. But its low tenacity greatly hinders its application area. Therefore, the preparation technology of alginate fibre has been as an important research direction in this area in recent years. The purpose of this article is to prepare the calcium alginate fibre with good properties by wet spinning. The structure and properties of this fibre are analyzed by scanning electron microscope，infrared spectrometer，thermal gravimetric analyzer and DSC.

Mechanism and Flow Control on the Mismatching of Impeller and Vaned Diffuser Caused by Inlet Prewhirl for Centrifugal Compressors

2016 ◽  
Author(s):  
Qiangqiang Huang ◽  
Xinqian Zheng ◽  
Aolin Wang
Keyword(s):  
Flow Control ◽  
Control Method ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Vaned Diffuser ◽  
Inlet Distortion ◽  
Computational Fluid Dynamics Cfd ◽  
Stagger Angle ◽  
Good Agreement ◽  
Matching Relation

Air often flows into compressors with inlet prewhirl, because it will obtain a circumferential component of velocity via inlet distortion or swirl generators such as inlet guide vanes. A lot of research has shown that inlet prewhirl does influence the characteristics of components, but the change of the matching relation between the components caused by inlet prewhirl is still unclear. This paper investigates the influence of inlet prewhirl on the matching of the impeller and the diffuser and proposes a flow control method to cure mismatching. The approach combines steady three-dimensional Reynolds-averaged Navier-Stokes (RANS) simulations with theoretical analysis and modeling. The result shows that a compressor whose impeller and diffuser match well at zero prewhirl will go to mismatching at non-zero prewhirl. The diffuser throat gets too large to match the impeller at positive prewhirl and gets too small for matching at negative prewhirl. The choking mass flow of the impeller is more sensitive to inlet prewhirl than that of the diffuser, which is the main reason for the mismatching. To cure the mismatching via adjusting the diffuser vanes stagger angle, a one-dimensional method based on incidence matching has been proposed to yield a control schedule for adjusting the diffuser. The optimal stagger angle predicted by analytical method has good agreement with that predicted by computational fluid dynamics (CFD). The compressor is able to operate efficiently in a much broader flow range with the control schedule. The flow range, where the efficiency is above 80%, of the datum compressor and the compressor only employing inlet prewhirl and no control are just 25.3% and 31.8%, respectively. For the compressor following the control schedule, the flow range is improved up to 46.5%. This paper also provides the perspective of components matching to think about inlet distortion.

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