scholarly journals A simulation model for the need for intra-plant transport operation planning by AGV

2019 ◽  
Vol 9 (1) ◽  
pp. 606-612
Author(s):  
Gabriel Fedorko ◽  
Martin Vasil ◽  
Bibiana Podracka

AbstractIntra-plant transport has an important role in the systems of enterprise logistics. At present, automated transport systems (AGV) are used for its efficient operation, with minimal operator attendance. For the proper and reliable functioning of such a transport system, there is currently a wide range of methods, of which the method of computer simulation is increasingly dominant. In the application, however, it is necessary to take into account that the functioning of AGV systems is a very demanding process with high demands on the used simulation software. Within the article, it will be described the use of the method of additional programming, as an effective tool in the creation of a simulation model of the AGV system for the need of its planning. The model presents the possibilities of increasing of the output of the analyzed production process to more than 70%, and at the same time it indicates insufficient use of workplaces that in one case reaches the value about 10%. The application of this model pointed to the reduction of the number of workplaces by one and with this related increase of output of other workplace.

2019 ◽  
Vol 9 (1) ◽  
pp. 600-605 ◽  
Author(s):  
Gabriel Fedorko ◽  
Martin Vasil ◽  
Michaela Bartosova

AbstractIntra-plant transport systems within their operation directly impact on the performance of production systems. For their effective operation, it is, therefore, necessary to realize evaluation of operational performance and effectivity. For the realization of this type of evaluation, in addition to a wide range of sensors that can be difficult for installation and operation, we can also use indirect methods that are equally able to provide reliable operational characteristics. Indirect analytical methods are presented above all by the approach which is based on the use of simulation methods. The method of computer simulation provides a wide range of options for the evaluation of efficiency and performance. The paper describes the use of a simulation model created in the program Tecnomatix Plant Simulation for analyzing the supply of production workplaces within the MilkRun system.


2021 ◽  
Vol 11 (5) ◽  
pp. 2425
Author(s):  
Igor Bychkov ◽  
Alexander Kazakov ◽  
Anna Lempert ◽  
Maxim Zharkov

Among the micro-logistic transport systems, railway stations should be highlighted, such as one of the most important transport infrastructure elements. The efficiency of the transport industry as a whole depends on the quality of their operation. Such systems have a complex multi-level structure, and the incoming traffic flow often has a stochastic character. It is known that the most effective approach to study the operation of such systems is mathematical modeling. Earlier, we proposed an approach to transport hub modeling using multiphase queuing systems with a batch Markovian arrival process (BMAP) as an incoming flow. In this paper, we develop the method by applying more complex models based on queuing networks that allow us to describe in detail the route of requests within an object with a non-linear hierarchical structure. This allows us to increase the adequacy of modeling and explore a new class of objects—freight railway stations and marshalling yards. Here we present mathematical models of two railway stations, one of which is a freight railway station located in Russia, and the other is a marshalling yard in the USA. The models have the form of queuing networks with BMAP flow. They are implemented as simulation software, and a numerical experiment is carried out. Based on the numerical results, some “bottlenecks” in the structure of the studied stations are determined. Moreover, the risk of switching to an irregular mode of operation is assessed. The proposed method is suitable for describing a wide range of cargo and passenger transport systems, including river ports, seaports, airports, and multimodal transport hubs. It allows a primary analysis of the hub operation and does not need large statistical information for parametric identification.


2020 ◽  
Vol 12 (23) ◽  
pp. 9818
Author(s):  
Gabriel Fedorko ◽  
Vieroslav Molnár ◽  
Nikoleta Mikušová

This paper examines the use of computer simulation methods to streamline the process of picking materials within warehouse logistics. The article describes the use of a genetic algorithm to optimize the storage of materials in shelving positions, in accordance with the method of High-Runner Strategy. The goal is to minimize the time needed for picking. The presented procedure enables the creation of a software tool in the form of an optimization model that can be used for the needs of the optimization of warehouse logistics processes within various types of production processes. There is a defined optimization problem in the form of a resistance function, which is of general validity. The optimization is represented using the example of 400 types of material items in 34 categories, stored in six rack rows. Using a simulation model, a comparison of a normal and an optimized state is realized, while a time saving of 48 min 36 s is achieved. The mentioned saving was achieved within one working day. However, the application of an approach based on the use of optimization using a genetic algorithm is not limited by the number of material items or the number of categories and shelves. The acquired knowledge demonstrates the application possibilities of the genetic algorithm method, even for the lowest levels of enterprise logistics, where the application of this approach is not yet a matter of course but, rather, a rarity.


Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2266
Author(s):  
Hongshen Li ◽  
Hongrui Liu ◽  
Yufang Li ◽  
Jilin Nan ◽  
Chen Shi ◽  
...  

Extracting ethanol by steam directly from fermented solid-state bagasse is an emerging technology of energy-efficient bioethanol production. With continuous solid-state distillation (CSSD) approach, the vapor with more than 25 wt% ethanol flows out of the column. Conventionally, the vapor was concentrated to azeotrope by rectification column, which contributes most of the energy consumption in ethanol production. As an alternative, a process integrating CSSD and vapor permeation (VP) membrane separation was tested. In light of existing industrial application of NaA zeolite hydrophilic membrane for dehydration, the prospect of replacing rectification operation with hydrophobic membrane for ethanol enriching was mainly analyzed in this paper. The separation performance of a commercial PDMS/PVDF membrane in a wide range of ethanol–water-vapor binary mixture was evaluated in the experiment. The correlation of the separation factor and permeate flux at different transmembrane driving force was measured. The mass and energy flow sheet of proposed VP case and rectification case were estimated respectively with process simulation software based on experimental data. Techno-economic analysis on both cases was performed. The results demonstrated that the additional VP membrane cost was higher than the rectification column, but a lower utilities cost was required for VP. The discount payback period of supplementary cost for VP case was determined as 1.81 years compared with the membrane service lifetime of 3 years, indicating that the hybrid CSSD-VP process was more cost effective and energy efficient.


2021 ◽  
Author(s):  
XueTao Wei ◽  
caixue yue ◽  
DeSheng Hu ◽  
XianLi Liu ◽  
YunPeng Ding ◽  
...  

Abstract The processed surface contour shape is extracted with the finite element simulation software, and the difference value of contour shape change is used as the parameters of balancing surface roughness to construct the infinitesimal element cutting finite element model of supersonic vibration milling in cutting stability domain. The surface roughness trial scheme is designed in the central composite test design method to analyze the surface roughness test result in the response surface methodology. The surface roughness prediction model is established and optimized. Finally, the finite element simulation model and surface roughness prediction model are verified and analyzed through experiment. The research results show that, compared with the experiment results, the maximum error of finite element simulation model and surface roughness prediction model is 30.9% and12.3%, respectively. So, the model in this paper is accurate and will provide the theoretical basis for optimization study of auxiliary milling process of supersonic vibration.


2018 ◽  
Vol 203 ◽  
pp. 03005
Author(s):  
Idzham Fauzi Mohd Ariff ◽  
Mardhiyah Bakir

A dynamic simulation model was developed, calibrated and validated for a petrochemical plant in Terengganu, Malaysia. Calibration and validation of the model was conducted based on plant monitoring data spanning 3 years resulting in a model accuracy (RMSD) for effluent chemical oxygen demand (COD), ammoniacal nitrogen (NH3-N) and total suspended solids (TSS) of ±11.7 mg/L, ±0.52 mg/L and ± 3.27 mg/L respectively. The simulation model has since been used for troubleshooting during plant upsets, planning of plant turnarounds and developing upgrade options. A case study is presented where the simulation model was used to assist in troubleshooting and rectification of a plant upset where ingress of a surfactant compound resulted in high effluent TSS and COD. The model was successfully used in the incident troubleshooting activities and provided critical insights that assisted the plant operators to quickly respond and bring back the system to normal, stable condition.


2021 ◽  
Vol 69 (1) ◽  
pp. 148-178
Author(s):  
Radoje Jevtić

Introduction/purpose: Safety in high residential buildings presents a very important and always actual task. In case of some unforeseen and dangerous occurrences, their residents must be evacuated. Fire, earthquakes, and terrorism are only some of such situations. The speed of evacuation from high residential buildings depends on many different factors. A particularly difficult and complex evacuation task concerns buildings without fire escape stairs. Methods: The modeling method was used in this paper. Based on a real object - a residential building, an appropriate simulation model was realized in appropriate simulation software. Results: The results of this paper have shown that, out of four scenarios, the fastest evacuation was for the evacuation speed of 1.75 m/s. The first two scenarios did not report any jams, unlike the third and fourth scenario; in the third scenario, the occupants' speeds were 0.75 m/s and 1.25 m/s while in the fourth scenario, the simulated occupants' speeds were from 0.75 m/s to 1.75 m/s. Conclusion:The usage of appropriate simulation software enables fast, precise, safe and cheap calculation of evacuation times and it can significantly improve evacuation procedures and evacuation strategies.


2021 ◽  
Vol 15 (4) ◽  
pp. 518-523
Author(s):  
Ratko Stanković ◽  
Diana Božić

Improvements achieved by applying linear programming models in solving optimization problems in logistics cannot always be expressed by physically measurable values (dimensions), but in non-dimensional values. Therefore, it may be difficult to present the actual benefits of the improvements to the stake holders of the system being optimized. In this article, a possibility of applying simulation modelling in quantifying results of optimizing cross dock terminal gates allocation is outlined. Optimal solution is obtained on the linear programming model by using MS Excel spreadsheet optimizer, while the results are quantified on the simulation model, by using Rockwell Automation simulation software. Input data are collected from a freight forwarding company in Zagreb, specialized in groupage transport (Less Than Truckload - LTL).


Author(s):  
Paulo C. C. Faria

Electroexplosive devices, EEDs or squibs (an electric resistance encapsulated by a primary explosive), fundamentally convert electrical energy into heat, solely to start off an explosive chemical reaction. Obviously, the EED activation shall not happen by accident or, even worse, by intentional exogenous influence. From an ordinary differential equation (ODE), which describes this device thermal behaviour for both continuous and pulsed electrical excitation, a remarkable, but certainly not intuitive, dependence of the temperature response on the heat transfer process time-constant is verified: the EED temperature profile dramatically changes as the time-constant spans a wide range of values, from much lesser than the pulse width to much greater than the pulse period. On the basis of this dependence, important recommendations, concerning the EED safety (and efficient) operation, are presented.


Author(s):  
Volodymyr Sysoiev ◽  
Viktoria Pysmak

 The main theoretical and methodological provisions of diagnostics of enterprise logistic activity as a tool of management process are investigated, it provides timely response to problems in organization of the enterprise logistics system and creation of preconditions for increasing the efficiency of its logistic activity. The mechanism of diagnostics of enterprise logistic activity in the form of a complex system, which integrates indicators, methods, special measures and procedures of research of its results in the conditions of various influence factors is proposed, is based on the basic principles of economic diagnostics and aims at achieving the goals of diagnostics. The essence of the main components of the diagnostic mechanism of enterprise logistic activity is revealed, their variety, interdependence and peculiarities of application are shown, that provides complexity and consistency in the study of a wide range of issues of organization and operation of the enterprise logistics system, as well as in evaluating the effectiveness of logistic solutions.  


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