scholarly journals Model-Based Virtual Components in Event-Based Controls: Linking the FMI and IEC 61499

2020 ◽  
Vol 10 (5) ◽  
pp. 1611
Author(s):  
Michael H. Spiegel ◽  
Edmund Widl ◽  
Bernhard Heinzl ◽  
Wolfgang Kastner ◽  
Nabil Akroud
Keyword(s):  
Real Time ◽  
Discrete Event ◽  
Simulation Models ◽  
Hybrid Plant ◽  
Seamless Integration ◽  
Quality Of Control ◽  
Automation Systems ◽  
Coupling Algorithm ◽  
Event Based ◽  
Iec 61499

Various development and validation methods for cyber-physical systems such as Controller-Hardware-in-the-Loop (C-HIL) testing strongly benefit from a seamless integration of (hardware) prototypes and simulation models. It has been often demonstrated that linking discrete event-based control systems and hybrid plant models can advance the quality of control implementations. Nevertheless, high manual coupling efforts and sometimes spurious simulation artifacts such as glitches and deviations are observed frequently. This work specifically addresses these two issues by presenting a generic, standard-based infrastructure referred to as virtual component, which enables the efficient coupling of simulation models and automation systems. A novel soft real-time coupling algorithm featuring event-accurate synchronization by extrapolating future model states is outlined. Based on considered standards for model exchange (FMI) and controls (IEC 61499), important properties such as real-time capabilities are derived and experimentally validated. Evaluation demonstrates that virtual components support engineers in efficiently creating C-HIL setups and that the novel algorithm can feature accurate synchronization when conventional approaches fail.

A Fiber-Optic-Based Protocol for Manufacturing System Networks: Part II—Statistical Analysis

1992 ◽  
Vol 114 (1) ◽  
pp. 121-131 ◽  
Author(s):  
A. Ayyagari ◽  
A. Ray
Keyword(s):  
Statistical Model ◽  
Real Time ◽  
Conceptual Development ◽  
Fiber Optic ◽  
Discrete Event ◽  
Simulation Models ◽  
Distribution Functions ◽  
Computer Integrated Manufacturing ◽  
Event Simulation ◽  
Arrival Processes

Conceptual development, architecture, statistical and simulation models, and the results of test and verification of a fiber-optic-based protocol have been reported in a sequence of two papers. The protocol uses the unidirectional bus topology and is specifically designed for computer integrated manufacturing (CIM) networks. The architecture of the protocol is formulated in Part I [1]. In this second part, a statistical model of the proposed protocol is formulated for analyzing the network-induced delays and pertinent results of analysis and simulation are presented for different scenarios of network traffic. The major assumptions in formulating the statistical model are: (1) message arrival processes for real-time (RT) and non-real-time (NRT) modes are independent and Markov; and (2) message lengths follow independent general distributions with known statistical properties. The Laplace-Stieltjes transforms of probability distribution functions of queueing delays for RT and NRT messages have been derived. The analytical results for the first two moments of both RT and NRT queueing delays have been compared with those obtained from discrete event simulation.

scholarly journals Simulation modelling to analyse the current level of utilisation of sections along a rail route

2013 ◽  
Vol 7 (2) ◽  
pp. 235-252 ◽  
Author(s):  
Clare Woroniuk ◽  
Marin Marinov
Keyword(s):  
Discrete Event ◽  
Simulation Models ◽  
Simulation Modelling ◽  
Simulation Software ◽  
Railway Freight ◽  
Collection Data ◽  
Current Scenario ◽  
Multi Method Approach ◽  
Event Based ◽  
Method Approach

This research aims to assess the level of utilisation of sections along a rail route by employing a series of simulation models. For the purposes of this research a multi method approach has been implemented which includes data collection, data analysis, modelling, model exploitation, measures of system performance and conclusion. Analytical methods and concepts in the study of railway freight lines and networks are presented. The discrete event based simulation models employed in this research have been implemented to study the rail route from Silla to Castellbisbal in Eastern Spain. The output from the models suggests that the current rate of utilisation is insignificant therefore different scenarios have been generated. These are based on changes to traffic rules, wherein the total number of services operated on the line is varied between the different scenarios. This paper concludes that it is possible to significantly increase the level of utilisation along the rail route from the current scenario. A contribution to knowledge is presented through the implementation of the simulation software Arena to study utilisation along a rail freight route.

scholarly journals Discrete-event modelling, simulation and control of a distributed manipulation environment

Robotica ◽  
1997 ◽  
Vol 15 (2) ◽  
pp. 181-198
Author(s):  
Fazel Naghdy ◽  
Naeem Anjum
Keyword(s):  
Dynamic Behaviour ◽  
Discrete Event ◽  
Simulation Models ◽  
Distributed Manipulation ◽  
Distributed Approach ◽  
Control Scheme ◽  
Event Based ◽  
And Control ◽  
Modelling Simulation

Conventional robotics has proved to be inflexible and non-generic. The concept of Distributed Manipulation Environment (DME) is introduced to overcome some of these shortcomings. This concept proposes a distributed approach to robotics and flexible automation. The work is concerned with modelling, simulation and event based control of DME. The modelling, conducted both at the atomic and the coupled level, is quite generic and provides a framework for static and dynamic behaviour analysis of DME systems. The simulation models serve as a mean of performance evaluation of the system on a computer before the actual implementation in real time. The event-based controller provides a simple and robust control scheme. The controller, itself, can be tested, validated and finely tuned through simulation before implementation. The feasibility of the modelling technique is demonstrated through a case study.

scholarly journals Simulation modeling and analysis of primary health center operations

SIMULATION ◽  
2021 ◽  
pp. 003754972110309
Author(s):  
Mohd Shoaib ◽  
Varun Ramamohan
Keyword(s):  
Resource Utilization ◽  
Waiting Times ◽  
Discrete Event ◽  
Simulation Models ◽  
Modeling And Analysis ◽  
Healthcare Facilities ◽  
Event Simulation ◽  
Analytical Approximations ◽  
Primary Health ◽  
Generic Modeling

We present discrete-event simulation models of the operations of primary health centers (PHCs) in the Indian context. Our PHC simulation models incorporate four types of patients seeking medical care: outpatients, inpatients, childbirth cases, and patients seeking antenatal care. A generic modeling approach was adopted to develop simulation models of PHC operations. This involved developing an archetype PHC simulation, which was then adapted to represent two other PHC configurations, differing in numbers of resources and types of services provided, encountered during PHC visits. A model representing a benchmark configuration conforming to government-mandated operational guidelines, with demand estimated from disease burden data and service times closer to international estimates (higher than observed), was also developed. Simulation outcomes for the three observed configurations indicate negligible patient waiting times and low resource utilization values at observed patient demand estimates. However, simulation outcomes for the benchmark configuration indicated significantly higher resource utilization. Simulation experiments to evaluate the effect of potential changes in operational patterns on reducing the utilization of stressed resources for the benchmark case were performed. Our analysis also motivated the development of simple analytical approximations of the average utilization of a server in a queueing system with characteristics similar to the PHC doctor/patient system. Our study represents the first step in an ongoing effort to establish the computational infrastructure required to analyze public health operations in India and can provide researchers in other settings with hierarchical health systems, a template for the development of simulation models of their primary healthcare facilities.

scholarly journals Assessing asset monitoring levels for maintenance operations

2015 ◽  
Vol 26 (5) ◽  
pp. 632-659 ◽  
Author(s):  
Abdullah A Alabdulkarim ◽  
Peter Ball ◽  
Ashutosh Tiwari
Keyword(s):  
Asset Management ◽  
Business Models ◽  
Discrete Event ◽  
Dynamic Modelling ◽  
Simulation Models ◽  
Content Type ◽  
Event Simulation ◽  
Product Service ◽  
Asset Monitoring ◽  
The Impact

Purpose – Asset management has recently gained significance due to emerging business models such as Product Service Systems where the sale of asset use, rather than the sale of the asset itself, is applied. This leaves the responsibility of the maintenance tasks to fall on the shoulders of the manufacturer/supplier to provide high asset availability. The use of asset monitoring assists in providing high availability but the level of monitoring and maintenance needs to be assessed for cost effectiveness. There is a lack of available tools and understanding of their value in assessing monitoring levels. The paper aims to discuss these issues. Design/methodology/approach – This research aims to develop a dynamic modelling approach using Discrete Event Simulation (DES) to assess such maintenance systems in order to provide a better understanding of the behaviour of complex maintenance operations. Interviews were conducted and literature was analysed to gather modelling requirements. Generic models were created, followed by simulation models, to examine how maintenance operation systems behave regarding different levels of asset monitoring. Findings – This research indicates that DES discerns varying levels of complexity of maintenance operations but that more sophisticated asset monitoring levels will not necessarily result in a higher asset performance. The paper shows that it is possible to assess the impact of monitoring levels as well as make other changes to system operation that may be more or less effective. Practical implications – The proposed tool supports the maintenance operations decision makers to select the appropriate asset monitoring level that suits their operational needs. Originality/value – A novel DES approach was developed to assess asset monitoring levels for maintenance operations. In applying this quantitative approach, it was demonstrated that higher asset monitoring levels do not necessarily result in higher asset availability. The work provides a means of evaluating the constraints in the system that an asset is part of rather than focusing on the asset in isolation.

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