Reza Vatankhah Barenji

Flexible testing platform for employment of RFID-enabled multi-agent system on flexible assembly line

Abstract The success of a flexible assembly line (FAL) depends on efficacious scheduling and control architecture. However, the scheduling and control architectures currently employed in FALs lack the flexibility and reconfiguration capacity to manage disturbances when they occur. Consequently, the system performance rapidly degrades when the system operation is interrupted. The objective of this study is to examine the potential enhancement of FAL performance through the use of a radio-frequency-identification-enabled multi-agent scheduling and control system (RFID-enabled MASCS). A simulation test platform is developed for the examination of an RFID-enabled MASCS in a FAL, and several system performance measures are considered in the simulation test platform. The results indicate that the RFID-enabled MASCS can increase the uptime productivity and production rate of a FAL. A real case-study test is performed, and a 22% decrease in lead time along with significant improvements in other system performance indicators are observed, especially when a series of disturbances occur within the examined assembly machine.

A framework for structural modelling of an RFID-enabled intelligent distributed manufacturing control system

A modern manufacturing facility typically contains several distributed control systems, such as machining stations, assembly stations, and material handling and storage systems. Integrating Radio Frequency Identification (RFID) technology into these control systems provides a basis for monitoring and configuring their components in real-time. With the right structural modelling, it is then possible to evaluate designs and translate them into new operational applications almost immediately. This paper proposes an architecture for the structural modelling of an intelligent distributed control system for a manufacturing facility, by utilising RFID technology. Emphasis is placed on a requirements analysis of the manufacturing system, the design of RFID-enabled intelligent distributed control systems using Unified Modelling Language (UML) diagrams, and the use of efficient algorithms and tools for the implementation of these systems.

Wear properties of Al–Al2O3/TiB2 surface hybrid composite layer prepared by friction stir process

In this study, surface hybrid composite was fabricated on Al6061 base sheets using friction stir processing (FSP). Samples were subjected to various numbers of FSP passes from one to four with Al2O3/TiB2 powder. Influence of number of FSP passes was studied on distribution of Al2O3/TiB2 particles in aluminium matrix, microstructure, hardness, and wear properties of specimens. The results showed that increase in the number of passes causes a more uniform dispersion of composite particles and thus, decreases particles clustering. In addition, an increase in the number of FSP passes was found to decrease the matrix grain size of the surface hybrid composite. It was observed that the hardness increased as the number of passes increased due to presence and pinning effect of hard Al2O3/TiB2 particles. Also, at higher number of passes, the surface hybrid composite wear resistance was increased.

Effect of tool traverse speed on microstructure and mechanical performance of friction stir welded 7020 aluminum alloy

The effect of tool traverse speed on microstructure and mechanical properties of friction stir welded 7020-T6 aluminum alloy was investigated. For this purpose, 5 mm thick 7020-T6 aluminum alloy plates were friction stir welded at traverse speeds of 50, 100, 150, and 200 mm/min and constant rotational speed of 900 r/min. Also, the peak temperatures of the joints during friction stir welding were recorded by accurate thermocouples. Moreover, the microstructure, hardness, tensile properties, and fracture surfaces of the joints were examined. The results showed that increasing the tool traverse speeds from 50 to 200 mm/min decreased the peak temperature from 331 ℃ to 211 ℃, and hence caused to lower heat input during friction stir welding. Furthermore, the higher hardness and ultimate tensile strength of the joints welded at higher traverse speeds was related to the grain boundary, precipitation, and substructure strengthening mechanisms. In addition, the fracture surfaces of the joints welded at higher heat input conditions showed more ductile mode in comparison with those welded at lower heat input condition, which confirmed the lower tensile elongation of the joints welded at higher traverse speeds.

A mathematical model and simulated annealing algorithm for solving the cyclic scheduling problem of a flexible robotic cell

Flexible robotic cells are used to produce standardized items at a high production speed. In this study, the scheduling problem of a flexible robotic cell is considered. Machines are identical and parallel. In the cell, there is an input and an output buffer, wherein the unprocessed and the finished items are kept, respectively. There is a robot performing the loading/unloading operations of the machines and transporting the items. The system repeats a cycle in its long run. It is assumed that each machine processes one part in each cycle. The cycle time depends on the order of the actions. Therefore, determining the order of the actions to minimize the cycle time is an optimization problem. A new mathematical model is presented to solve the problem, and as an alternative, a simulated annealing algorithm is developed for large-size problems. In the simulated annealing algorithm, the objective function value of a given solution is computed by solving a linear programming model which is the first case in the literature to the best of our knowledge. Several numerical examples are solved using the proposed methods, and their performances are evaluated.

Effect of tool pin profile on the microstructure and mechanical properties of friction stir processed Al6061/Al2O3—TiB2 surface hybrid composite layer

The Al6061/Al2O3–TiB2 surface hybrid composites were produced using friction stir processing. The effect of the tool pin profile was investigated on the microstructure and mechanical properties including hardness and wear resistance. For this purpose, simple cylindrical, threaded cylindrical, taper, square, and triangular pin profiles were used. X-ray diffraction analysis and transmission electron microscopy were used to characterize the used powder. Light and scanning electron microscopes were utilized for the microstructural observations of the processed samples. The results showed that the distribution of Al2O3–TiB2 particles in the specimens produced using square and triangular tool pin profiles was more uniform due to their tool geometry, which results in better stirring of the material and good material flow. Consequently, a greater reduction of particle clustering was observed, and hence the mechanical properties were enhanced. Moreover, the samples produced using square and triangular pin profiles exhibited more grain refinement than the other samples. More uniform structure, less clustering, and finer grains produced by square and triangular pin profiles caused higher hardness and wear resistance of the samples.

Improving multi-agent manufacturing control system by indirect communication based on ant agents

Manufacturing control systems are facing difficulty on adopting agility in today’s dynamic environment. Much research has been conducted on the use of multi-agent systems to facilitate this transition. In our previous work, a radio frequency identification–enabled multi-agent-based manufacturing control system was introduced for flexible manufacturing systems. In that control system, a direct coordination mechanism coordinates the agents. However, the decision-making response of the control system to disturbances was low and caused the agents to spend more time on processing messages than doing the actual job. Thus, in this article, we propose an indirect coordination mechanism based on ant colony intelligence aiming to improve the self-organization and processing time of the system. The new system utilizes the stigmergy mechanism for cooperation among the agents. Furthermore, ant agents are created by the existing agents to enable communication among them. The proposed new mechanism was implemented in a flexible assembly line. The simulation results of a case study considering shop floor problems indicates, for most performance measures, that the radio frequency identification–enabled multi-agent-based manufacturing control system integrated with indirect coordination mechanism performs better in comparison with the radio frequency identification–enabled multi-agent-based manufacturing control system integrated with direct coordination mechanism.Manufacturing control systems are facing difficulty on adopting agility in today’s dynamic environment. Much research has been conducted on the use of multi-agent systems to facilitate this transit...

Modeling mechanical properties of FSW thick pure copper plates and optimizing it utilizing artificial intelligence techniques

Friction stir welding (FSW) is an innovative solid state joining technique and has been employed in aerospace, rail, automotive and marine industries for joining aluminum, magnesium, zinc and copper alloys. In this process, parameters play a major role in deciding the weld quality these parameters. Using predictive modelling for mechanical properties of FSW not only reduce experiments but also is created standard model for predict outcomes. Therefore, this paper is undertaken to develop a model to predict the microstructure and mechanical properties of FSW. The proposed model is based on Ring Probabilistic logic Neural Network (RPLNN) and optimize it utilizing Genetic Algorithms (GA). The simulation results show that performance of the RPLNN algorithm with utilizing Genetic Algorithm optimizing technique compared to real data is reliable to deal with function approximation problems, and it is capable of achieving a solution in few convergence time steps with powerful and reliable results.

Towards an Automated Guided Vehicle (AGV) in Sprinkler Irrigation

The new technologies play a more and more important role in improving the productivity over the agriculture industry. The irrigation machines as well as technologies have significant roles. Nowadays, intelligent systems and robots are employed supplementary on irrigation systems, aiming to decrease the manpower defects as well as save on energy and time. In the present work, the sprinkler irrigation classic method (moving sprinkler) is considered in detail and some of the shortcomings of this method are highlighted. Since, in sprinkler irrigation classic method after each period of irrigation the position of the sprinklers have to be replaced by manpower, this difficulty makes the method impractical from time, cost and energy points of view. The purpose of this study is to propose and develop an automatic guide vehicle (AGV) with the capability to change sprinklers timely and on appropriate positions for sprinkler irrigation classic method. The designed AGV is simulated on computer environment and the results show acceptable outcomes.

Quantifying the advantage of a kitting system using Petri nets: a case study in Turkey, modeling, analysis, and insights

In case a paradigm is introduced to improve the operation of manufacturing systems, it is important to anticipate the performance of the system before expensive and time-consuming implementation. In this study, we provide the use of Petri nets in order to quantify the possible advantage of kitting feeding method in an assembly line through a case study. In particular, Petri nets have been developed through the integration of the resource-oriented and process-oriented modeling approaches and then a detailed quantitative analysis of the current and proposed system have been performed. The results and the analysis obtained from the Petri nets are used to give an idea about the anticipated performance of the proposed system before a possible implementation. Therefore, results can easily be used to aid decision-making.