Search results for "Manufacturing system"

Reconfiguration: a key to handle exceptions and performance deteriorations in manufacturing operations

2005

During a manufacturing operation, exceptions may occur dynamically and unpredictably. Their occurrence may lead to the degradation of system performance or, in the worst case scenario may interrupt the production process by causing errors in the schedule plan. This paper classifies three families of exceptions: (1) out-of-order events such as machine breakdowns, (2) operational out-of-ordinary events such as rush orders and (3) deteriorations of manufacturing resource performance such as reductions of machines' utilization. In all cases, in order to maintain an adequate level of system performance, it is necessary to detect exceptions, to diagnose them quickly and to recover them by taking …

Standards Based Generation of a Virtual Factory Model

2016

International audience; Developing manufacturing simulation models usually requires experts with knowledge of multiple areas including manufacturing, modeling, and simulation software. The expertise requirements increase for virtual factory models that include representations of manufacturing at multiple resolution levels. This paper reports on an initial effort to automatically generate virtual factory models using manufacturing configuration data in standard formats as the primary input. The execution of the virtual factory generates time series data in standard formats mimicking a real factory. Steps are described for auto- generation of model components in a software environment primari…

Robust control of uncertain multi-inventory systems via linear matrix inequality

2008

We consider a continuous time linear multi inventory system with unknown demands bounded within ellipsoids and controls bounded within ellipsoids or polytopes. We address the problem of "-stabilizing the inventory since this implies some reduction of the inventory costs. The main results are certain conditions under which "-stabilizability is possible through a saturated linear state feedback control. All the results are based on a Linear Matrix Inequalities (LMIs) approach and on some recent techniques for the modeling and analysis of polytopic systems with saturations.

Trends in Metal Cutting Theory and Practice

2017

This chapter provides the state-of-the-art manufacturing systems that utilize various machining technologies in different manufacturing sectors. It highlights the challenges of the 21st-century manufacturing environment and characterizes numerous driven factors in modern machining technologies. They include more-established technologies, such as High-Speed Machining/Cutting, High-Performance Machining/Cutting, High-Efficiency Machining or currently developed ones, such as resource- and energy-efficient (generally sustainable) and hybrid machining. Practical examples and charts that document their importance in modern manufacturing are provided. Finally, some important future trends are over…

On the Impact of Wireless Communications on Controlling a Two-Dimensional Gantry System

2019

Abstract Industrial wireless is essential to achieve the vision of future manufacturing systems which are highly dynamic and reconfigurable, and communicate large amounts of data. Main challenges of wireless deployment include the stochastic nature of the wireless channels and the harsh industrial transmission environment. In this work, a typical two-dimensional gantry system is controlled by a local controller which receives G-code commands wirelessly over a Wi-Fi network. The industrial wireless channel is replicated using a radio frequency (RF) channel emulator where various scenarios are considered and various wireless channel parameters are studied. The movement of the gantry system to…

NAMRC 49 Fast-Tracked Research Papers to Journal of Manufacturing Systems and Journal of Manufacturing Processes

2021

A hierarchic approach to production planning and scheduling of a flexible manufacturing system

1999

Abstract The paper deals with the problem of improving the machine utilization of a flexible manufacturing cell. Limited tool magazine space of the machines turns out to be a relevant bottleneck. A hierarchic approach for this problem is proposed. At the upper level, sets of parts that can be concurrently processed (batches) are determined. At the lower levels, batches are sequenced, linked, and scheduled. Methods taken from the literature are used for the solution of the latter subproblems, and an original mixed integer programming model is formulated to determine batches. The proposed methods are discussed on the basis of computational experience carried out on real instances.

Application of learning pallets for real-time scheduling by use of artificial neural network

2011

Author's version of a chapter in the book: 5th International Conference on Software, Knowledge Information, Industrial Management and Applications (SKIMA). Also available from the publisher at: http://dx.doi.org/10.1109/SKIMA.2011.6089986 Generally, this paper deals with the problem of autonomy in logistics. Specifically here, a complex problem in inbound logistics is considered as real-time scheduling in a stochastic shop floor problem. Recently, in order to comply with real-time decisions, autonomous logistic objects have been suggested as an alternative. Since pallets are common used objects in carrying materials (finished or semi-finished), so they have the possibility to undertake the …

Average flow constraints and stabilizability in uncertain production-distribution systems

2009

We consider a multi-inventory system with controlled flows and uncertain demands (disturbances) bounded within assigned compact sets. The system is modelled as a first-order one integrating the discrepancy between controlled flows and demands at different sites/nodes. Thus, the buffer levels at the nodes represent the system state. Given a long-term average demand, we are interested in a control strategy that satisfies just one of two requirements: (i) meeting any possible demand at each time (worst case stability) or (ii) achieving a predefined flow in the average (average flow constraints). Necessary and sufficient conditions for the achievement of both goals have been proposed by the aut…

Task scheduling control of BGA solder joint process in flexible manufacturing system

2006

This paper describes an open loop control method of the solder joint process in a rework station for faulty printed circuit board (PCBs) containing electronic components in packages ball grid arrays (BGAs). In particular, a mathematical model describing the solder joint process is, first of all, obtained. Then, the desired thermal profile of the junctions BGA-PCB is determined according to the physical constraints of the rework station framework. The control parameters corresponding to the above desired thermal profile are identified using the above mathematical model. Finally, the open loop control algorithm is implemented on the supervisor interface of the rework station in order to carri…