Flexible Manufacturing Control Research Articles

Developing a Flexible Manufacturing Control System Considering Mixed Uncertain Predictive Maintenance Model: a Simulation-Based Optimization Approach

Developing a Flexible Manufacturing Control System Considering Mixed Uncertain Predictive Maintenance Model: a Simulation-Based Optimization Approach

Combining Life Cycle Assessment and Manufacturing System Simulation: Evaluating Dynamic Impacts from Renewable Energy Supply on Product-Specific Environmental Footprints

The eco-efficiency of actual production processes is still one dominating research area in engineering. However, neglecting the environmental impacts of production equipment, technical building services and energy supply might lead to sub-optimization or burden-shifting and thus reduced effectiveness. As an established method used in sustainability management, Life Cycle Assessment aims at calculating the environmental impacts from all life cycle stages of a product or system. In order to cope with shortcomings of the static character of life cycle models and data gaps this approach combines Life Cycle Assessment with manufacturing system simulation. Therefore, the two life cycles of product and production system are merged to assess environmental sustainability on product level. Manufacturing simulation covers the production system and Life Cycle Assessment is needed to relate the results to the final product. This combined approach highlights the influences from dynamic effects in manufacturing systems on resulting life cycle impact from both product and production system. Furthermore, the importance of considering indirect peripheral equipment and its effects on the manufacturing system operation in terms of output and energy demands is underlined. The environmental flows are converted into impacts for the five recommended environmental impact categories. Thus, it can be demonstrate that Life Cycle Assessment can enhance the process simulation and help identify hot-spots along the life cycle. The combined methodology is applied for analysing a case study in fourteen scenarios for the integration of volatile energy sources into energy flexible manufacturing control.

Stretch bending and springback of profile in the loading method of prebending and tension

In view of the stretch bending process of the profile, an expanded study is carried out for the forming and springback of the profile with any cross-section in the loading method of prebending and tension (prebending-tension). Base on the analysis of stress and strain in cross section, the stretch bending is divided into twelve cases, then the corresponding determination conditions and general springback analysis step are established. According to the analytical model, the deformation types and springback of rectangular and U-section profiles are predicted and verified by numerical simulations and experiments. The comparative study of the results by three methods clearly demonstrates that the prediction of springback is reliable. Moreover, the springback analysis of stretch bending in the loading methods of prebending-tension show that, when the bending radius is constant, the bigger the tension is, the smaller the springback is; under the condition of equal tension, the smaller the bending radius is, the smaller the springback is; the springback laws of both profiles consistent The accurately predicted springback values can provide a theoretical basis for flexible manufacturing and intelligent control of the stretch bending of profiles.

Reactive control of overall power consumption in flexible manufacturing systems scheduling: A Potential Fields model

In recent years, designing “energy-aware manufacturing scheduling and control systems” has become more and more complex due to the increasing volatility and unpredictability of energy availability, supply and cost, and thus requires the integration of highly reactive behavior in control laws. The aim of this paper is to propose a Potential Fields-based flexible manufacturing control system that can dynamically allocate and route products to production resources to minimize the total production time. This control system simultaneously optimizes resource energy consumption by limiting energy wastage through the real-time control of resource states, and by dynamically controlling the overall power consumption taking the limited availability of energy into consideration. The Potential Fields-based control model was proposed in two stages. First, a mechanism was proposed to switch resources on/off reactively depending on the situation of the flexible manufacturing system (FMS) to reduce energy wastage. Second, while minimizing wastage, overall power consumption control was introduced in order to remain under a dynamically determined energy threshold. The effectiveness of the control model was studied in simulation with several scenarios for reducing energy wastage and controlling overall consumption. Experiments were then performed in a real FMS to prove the feasibility of the model. The superiority of the proposition is its high reactivity to manage production in real-time despite unexpected restrictions in the amount of energy available. After providing the limitations of the work, the conclusions and prospects are presented.

An Object-Oriented Approach for Flexible Manufacturing Control Systems Analysis and Design Using the Unified Modeling Language

In reacting to global competition and rapidly changing customer demands, industrial business organizations have developed a strong interest in flexible automation. The aim of flexible automation focuses on achieving agility in handling uncertainties from internal or external environments. Modeling complex structures, promoting reuse, and shortening the development time cycle are particularly significant aspects in the analysis and design of CIM systems, where heterogeneous elements have to be integrated in a complex control architecture. The design methodology for FMS control software involves the abstraction of an FMS and the estimation of the system performances. The aim of this activity is to suggest the optimal configuration of an FMS for given specifications, through simulation tools. In the software engineering field, object-oriented (OO) approaches have proven to be a powerful technique with respect to such aspects. The unified modeling language (UML), by using OO design methodologies, can offer reusability, extendibility, and modifiability in software design. Also, it bridges the gap that exists between the OO analysis and design area and the area of OO programming by creating an integrative metamodel of OO concepts. The specific goal of this paper is to formulate a new methodology for developing reusable, extendible, and modifiable control software for an FMS in an object-oriented environment. It is demonstrated that, with few diagrams, UML can be used to model such systems without being associated with other modeling tools.

A state-based modelling approach to develop component-based control software for flexible manufacturing systems

In recent years, component-based software engineering has emerged as an approach to create control software for flexible and adaptive manufacturing systems. This paper presents a state-based approach to model and design software components that can be used as building blocks for flexible manufacturing control software. Adiga and Cogez's (1993) framework for modelling object-oriented manufacturing software is extended to component-based modelling and work cell control programming. The benefits of using component-based software were fully demonstrated during configuration, integration and execution of Flexible Manufacturing System (FMS) work cell operation in the Miami University Computer Integrated Manufacturing Laboratory (CIMS Lab) by using the control software described in this paper. The software was developed using the Java Programming language and the JavaBeans component model. We emphasized generic features, reusability, ease of use, and ease of maintenance in the design of these software components. We also created simulated software components that can interact with, or replace, real system components for planning, debugging and testing purposes. Once generic software components are developed and stored in a library, users with little or no programming background can rapidly integrate them into control software by using visual design tools.

A system architecture for holonic manufacturing planning and control (EtoPlan)

In this paper, we present the system architecture of a flexible manufacturing planning and control system, named EtoPlan. The concept is based on the holonic control approach of building multiple and temporary hierarchies (holarchies). This paper describes the system architecture for flexible planning and control of activities and (groups of) Resources in a manufacture-to-order environment. The system architecture consists of generic control modules that can be applied on different hierarchical levels and for different kinds of manufacturing activities. The main function of the Resource Controller is the Determine Applicability function.

Design and Implementation of a Flexible Manufacturing Control System Using Neural Network

Design and implementation of a sequential controller based on the concept of artificial neural networks for a flexible manufacturing system are presented. The recurrent neural network (RNN) type is used for such a purpose. Contrary to the programmable controller, an RNN-based sequential controller is based on a definite mathematical model rather than depending on experience and trial and error techniques. The proposed controller is also more flexible because it is not limited by the restrictions of the finite state automata theory. Adequate guidelines of how to construct an RNN-based sequential controller are presented. These guidelines are applied to different case studies. The proposed controller is tested by simulations and real-time experiments. These tests prove the successfulness of the proposed controller performances. Theoretical as well as experimental results are presented and discussed indicating that the proposed design procedure using Elman's RNN can be effective in designing a sequential controller for event-based type manufacturing systems. In addition, the simulation results assure the effectiveness of the proposed controller to outperform the effect of noisy inputs.

Autonomous agents architectures and algorithms in flexible manufacturing systems

This paper investigates possible implementations of the autonomous agents concept in flexible manufacturing control. The implementation issues and the effectiveness of different control architectures and algorithms are analyzed by means of a simulation model of a flexible job shop. Extensive experimental results are reported, allowing the evaluation of the trade-off between the degree of autonomy and system performance.

Product flexibility in selecting manufacturing planning and control strategy

The manufacturing systems capable of producing several products simultaneously are frequently subject to changes in product types due to demand fluctuations. In such systems a product flexible manufacturing planning and control (MPC) strategy is needed to change from one product type to another with minimum deterioration to system performance levels. The objective of this research is to develop a systematic analysis and evaluation approach in order to compare the MRP-push and JIT-pull strategies quantitatively based on a product flexibility measure. A new product flexibility measure is developed based on the sensitivity to change concept and presented together with the implementation in a real manufacturing system. Simulation is used to compare the performance of a JIT-pull with an MRP-push strategy based on performance measures, e.g. manufacturing lead time, work-in-process inventory, backorders, machine utilization and throughput. The performances of the two strategies are evaluated in two scenarios: (i) a single product; (ii) a second product is added (the first product being simple and the second being complex in terms of processing). The impacts of adding the second product on the performance measures for the push and pull strategies are then assessed. A multi-attribute evaluation scheme is used to compare the two strategies where the attribute values are the change in performance measures as the second product is added. The proposed product flexibility measure is utilized in the interpretation of the results.

Autonomous agents architectures and algorithms in flexible manufacturing systems

This paper investigates possible implementations of the autonomous agents concept in flexible manufacturing control. The implementation issues and the effectiveness of different control architectures and algorithms are analyzed by means of a simulation model of a flexible job shop. Extensive experimental results are reported, allowing the evaluation of the trade-off between the degree of autonomy and system performance.

Guaranteeing Real-Time Behaviour in Adaptive Distributed Systems

Traditionally, real-time systems have been realized as isolated, embedded systems. Unfortunately, this approach does not longer suffice for future complex systems in application scenarios like flexible manufacturing, multimedia, robotics and process control. Often, there is a need to integrate external services through non real-time, object-oriented interfaces (e.g. CORBA).The most distinguishing requirement for these complex real-time systems is the need to adapt to dynamically changing conditions. Little work has been done on (operating) system mechanisms and algorithms that are flexible enough to cope with this new requirement. This paper presents an approach for an adaptive object-oriented system with integrated monitoring, dynamic execution time prediction and scheduling. Its applicability in a CORBA-like environment is exhibited.

Towards a Decentralized Reactive Intelligent FMS Controller

The paper presents an architecture for the flexible manufacturing control systems. The aim is to develop a particular decision-making system. The defined Controller architecture is open. It is organised into hierarchical levels according to the different decision time frames. The decision-making system is distributed among the levels, what allows reactivity and assignment of intelligence to the system. A generic model adaptable to any decision-making level, is presented. System flexibility, reactivity, robustness and reliability are expected benefits. To express system behaviour, the modelling methodology is based on the Use Case method.

Towards Building an Intelligent Flexible Manufacturing Control System

An approach to building up a distributed expert system for planning, scheduling and fault diagnosis, integrated with the conventional flexible manufacturing control system is proposed. The structure of the developed expert system shell is described. Some preliminary results for the operation of the expert system are given.

Design and Implementation of Production Systems for High Variety Electronics Assembly

Information technology companies are having to broaden their overall strategic view in deference to the premise that it is better to be market‐driven than technology‐led. Cost and technical performance are no longer the only considerations, as quality and service now demand equal recognition. The production of a high volume single item has given way to that of low volume multiple items, which in turn requires some modification of production systems and brings flexible manufacturing, Just‐in‐Time production and total quality control into sharper focus for the achievement of corporate objectives.

Prediction of Optimal Direct Digital Control System for Process Industries

The authors developed the first DDC System for Styrene Monomer Plant in 1969 and three DDC systems in 1970. Their first DDC was not profitable, and the three DDC systems were satisfied. After that, the authors experienced industries are Cement, Chemical, Detergent, Mayonase Bottle Conveying, Medicine, Petrochemical, Phono-disk making, Steel Making, Tapping Robot, Waste Water Biological Treatment, etc.Now the authors are planning for Dual-Hierachy-distributed-batch start-scheduled optimal control system for good manufacturing fermentation proceses in a medicine industry.The authors predict an optimal DDC system should have a flexible manufacturing control board that is an inflexible control board.