A Control Flow based Static Analysis of GRAFCET using Abstract Interpretation

The graphical modeling language GRAFCET is used as a formal specification language in industrial control design. This paper proposes a static analysis approach based on the control flow of GRAFCET using abstract interpretation to allow verification on specification level. GRAFCET has different elements leading to concurrent behavior, which in general results in a large state space. To get precise results and reduce the state space, we propose an analysis suitable for GRAFCET instances without concurrent behavior. We point out how to check for the absence of concurrency and present a flow-sensitive analysis for these GRAFCET instances. The proposed approach is evaluated on an industrial-sized example.Comment: \c{opyright} 2023 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other work

Unambiguous Interpretation of IEC 60848 GRAFCET based on a Literature Review

IEC 60848 GRAFCET is a standardized, graphical specification language for control functions. Because of the semiformal nature of IEC 60848, the details of specifications created with GRAFCET can be interpreted in different ways, possibly leading to faulty implementations. These ambiguities have been partially addressed in existing literature, but solved in different manners. Based on a literature review, this work aims at providing an overview of existing interpretations and, based on that, proposes a comprehensive interpretation algorithm for IEC 60848, which takes all relevant ambiguities from the literature review into account.Comment: Submitted to ETFA 2

A graphical interface based on grafcet for programming industrial robots off-line

This paper presents the current development stage of our approach to industrial robot programming, that is the graphical interface for our environment, that is based on the well-known Grafcet. Our approach focus on the modelling of the system, rather than on the robot. So, it will improve the programming and maintenance tasks, allowing the reuse of source code.Fundação para a Ciência e a Tecnologia (FCT

Aerodynamic performance evaluation of multi inner blades savonius rotor

Savonius wind turbine is the cheapest and simplest type of vertical axis wind turbines. This turbine is being utilized in various countries due to the simplistic design and low construction cost. However, this turbine suffers from low efficiency. For that, this study aims to increase the performance of the Savonius wind rotor in order to generate more useful power. In the present study, the aerodynamics performance of the Savonius wind turbine rotor with inner blades was investigated. The effect of number of inner blades, angle of inner blades, position of inner blades, and distance between the inner blades were evaluated under low and normal ranges of Tip Speed Ratio (TSR) through simulation and experimental work. A numerical investigation was adopted using ANSYS Fluent 19.1 software in order to determine the aerodynamic performance such as power coefficient (Cp) and torque coefficient (Ct). The numerical investigation was performed using two and three-dimensional simulations based on k-Ɛ/realizable turbulence model. Wind tunnel investigation was also carried out for the best-performed Savonius rotor configuration under the various parameters. Both simulation and experimental results were then compared for verification. In general, the results obtained showed that the performance of the Savonius rotor could be significantly improved by the addition of inner blades. The maximum enhancement of Cp was 41% for the case of single inner blade installed at 120o angle and tested at high TSR. As for the double inner blades, a maximum Cp of 13% was achieved when tested at low TSR (installed at 160o angle). The results also indicated that better performance of the Savonius rotor could be obtained when the spacing of inner blade was set at 0.02 m and 0.005 m for single and double inner blades, respectively. However, middle position of inner blades marked better performance for most of the cases. It can conclude that a significant enhancement of Savonius rotor performance can be achieved without high production cost and complex design involved. This solution would be very useful for generating high electricity in rural areas with a low cos

A support tool for teaching grafcet : engineering students' perceptions

Modeling discrete event systems with sequential behavior can be a very hard and complex task. Some formalisms are used in this context, such as: Petri Nets, Statecharts, Finite automata, Grafcet and others. Among these, Grafcet seems to be a good choice because it is easy: to learn, to understand and to use. Teaching Grafcet is then relevant within engineering courses concerned with Industrial Automation. A virtual laboratory, e-GRAFCET, developed and first tested in UTAD University; it is a new, easy-to-use multimedia e-educational tool to support the self-learning process of Grafcet. This paper, reports a study of e-GRAFCET use by the students of University of Minho. A questionnaire was prepared and students asked to fulfill it in a volunteer basis. The results were statistically analyzed and the scores compared. The overall objective is to understand how the tool helps students in their study, and consequently improve their learning off Grafcet, independently of their engineering background

Substitution-based approach for linguistic steganography using antonym

Steganography has been a part of information technology security since a long time ago. The study of steganography is getting attention from researchers because it helps to strengthen the security in protecting content message during this era of Information Technology. In this study, the use of substitution-based approach for linguistic steganography using antonym is proposed where it is expected to be an alternative to the existing substitution approach that using synonym. This approach still hides the message as existing approach but its will change the semantic of the stego text from cover text. A tool has been developed to test the proposed approach and it has been verified and validated. This proposed approach has been verified based on its character length stego text towards the cover text, bit size types of the secret text towards the stego text and bit size types of the cover text towards the stego text. It has also been validated using four parameters, which are precision, recall, f-measure, and accuracy. All the results showed that the proposed approach was very effective and comparable to the existing synonym-based substitution approach

Two Cases of Study for Control Reconfiguration of Discrete Event Systems (DES)

International audienceIn this paper, we propose two cases of study for control reconfiguration of Discrete Event Systems. The main contributions are based on a safe centralized and distributed control synthesis founded on timed properties. In fact, if a sensor fault is detected, the controller of the normal behavior is reconfigured to a timed controller where the timed information replaces the information lost on the faulty sensor. Finally, we apply our contribution to a manufacturing system to illustrate our results and compare between the two frameworks

SUPERVISORY CONTROL AND DATA ACQUISITION FOR A ROBOTIC ARM VIA GRAFCET

The aim of this report is to focus on the basic programming structure of PLC and its application in industry. This report emphasizes understanding of Grafcet language through the basic knowledge of ladder diagram method. A robotic arm will be programmed to do some specific tasks. The main programming language to be used would be Grafcet. Notably, since the language is relatively new, several aspects of the programming method would be required to be explored. Specific software named AUTOMGEN is available and it provides some features inclusive of pneumatic/electrical/hydraulic simulation module for any automation application and SCADA 3D process simulation. Programming of the Grafcet would be conducted by using State-by-State (SS) approach and classic truth table simplification. The truth table is to be constructed based on the timing diagram of the motions of the robotic arm. Previous work on the robotic arm controlled via PLC programming using ladder diagram had shown a successful achievement. In this project, Grafcet language is opted to be used for programming becauseof its concurrency for both simplicity and easy understanding. It would expect that a clear description of programming using Grafcet could be achieved and the general features of programming a PLC could be understood

Monitoring and Control of a Process by SCADA via Grafcet and Ladder Diagram Programming

This report discusses the development of a Supervisory Control and Data Acquisition (SCADA) system for the monitoring and control of a process using Programmable Logic Controller (PLC) via Grafcet and Ladder Diagram (LD) programming. The report explains the background and several methods to program a PLC. When dealing with a PLC, Grafcet is becoming the preferable method to work with because of its easiness and the clear flow of program. In this work, the Tidal Gate Control System (TGCS) is selected as a case study to investigate the advantages and disadvantages of Grafcet over LD. A literature review to track the achievements of researchers in using Grafcet and about Grafcet have been conducted. Procedure and tools required to develop TGCS are elucidated. Results on the implementation of the project are discussed. Programming the PLC to implement the monitoring and control of TGCS via Grafcet is more convenient compared to programming via LD. The recommendations on the future works of this project are also discussed