Search results

1 – 10 of 50
To view the access options for this content please click here
Article
Publication date: 1 March 2003

J.P. Kenné and E.K. Boukas

This paper deals with the production and preventive maintenance planning control problem for a multi‐machine flexible manufacturing system (FMS). A two‐level hierarchical…

Abstract

This paper deals with the production and preventive maintenance planning control problem for a multi‐machine flexible manufacturing system (FMS). A two‐level hierarchical control model is developed according to the discrepancy between the time scale of the discounting cost event and one of the machine state processes. The proposed model extends the classical singular perturbation approach by considering age‐dependent machine failure rates and controlling both production and preventive maintenance rates. We replace the stochastic optimal control problem by a deterministic one termed limiting control problem. With this approach, we compute an age‐dependent near‐optimal control policy of the stochastic initial control problem from the optimal solution of the equivalent limiting control problem. A numerical example is used to illustrate the procedure and to show the reduction of the control problem size.

Details

Journal of Quality in Maintenance Engineering, vol. 9 no. 1
Type: Research Article
ISSN: 1355-2511

Keywords

To view the access options for this content please click here
Article
Publication date: 6 March 2017

Ching-Min Lee

For most practical control system problems, the state variables of a system are not often available or measureable due to technical or economical constraints. In these…

Abstract

Purpose

For most practical control system problems, the state variables of a system are not often available or measureable due to technical or economical constraints. In these cases, an observer-based controller design problem, which is involved with using the available information on inputs and outputs to reconstruct the unmeasured states, is desirable, and it has been wide investigated in many practical applications. However, the investigation on a discrete-time singular Markovian jumping system is few so far. This paper aims to consider an observer-based control problem for a discrete-time singular Markovian jumping system and provides a set of easy-used conditions to the proposed control law.

Design/methodology/approach

According to the connotation of the separation principle extended from linear systems, a mode-dependent observer and a state-feedback controller is designed and carried out independently via two sets of derived necessary and sufficient conditions in terms of linear matrix inequalities (LMIs).

Findings

A set of necessary and sufficient conditions for an admissibility analysis problem related to a discrete-time singular Markovian jumping system is derived to be a doctrinal foundation for the proposed design problems. A mode-dependent observer and a controller for such systems could be designed via two sets of strictly LMI-based synthesis conditions.

Research limitations/implications

The proposed method can be applied to discrete-time singular Markovian jumping systems with transition probability pij > 0 rather than the ones with pii = 0.

Practical implications

The formulated problem and proposed methods have extensive applications in various fields such as power systems, electrical circuits, robot systems, chemical systems, networked control systems and interconnected large-scale systems. Take robotic networked control systems for example. It is recognized that the variance phenomena derived from network transmission, such as packets dropout, loss and disorder, are suitable for modeling as a system with Markovian jumping modes, while the dynamics of the robot systems can be described by singular systems. In addition, the packets dropout or loss might result in unreliable transmission signals which motivates an observer-based control problem.

Originality/value

Both of the resultant conditions of analysis and synthesis problems for a discrete-time singular Markovian jumping system are necessary and sufficient, and are formed in strict LMIs, which can be used and implemented easily via MATLAB toolbox.

Details

Engineering Computations, vol. 34 no. 1
Type: Research Article
ISSN: 0264-4401

Keywords

To view the access options for this content please click here
Article
Publication date: 14 May 2018

Guy Richard Kibouka, Donatien Nganga-Kouya, Jean-Pierre Kenné, Vladimir Polotski and Victor Songmene

The purpose of this paper is to find the optimal production and setup policies for a manufacturing system that produces two different types of parts. The manufacturing…

Abstract

Purpose

The purpose of this paper is to find the optimal production and setup policies for a manufacturing system that produces two different types of parts. The manufacturing system consists of one machine subject to random failures and repairs. Reconfiguring the machine to switch production from one type of product to another generates a non-production time and a significant cost.

Design/methodology/approach

This paper proposes an approach based on the development of optimal production and setup policies, taking into account the possibilities of undertaking the setup for all modes of the machine, and covering them at the end of setup. New optimality conditions are developed in terms of modified Hamilton-Jacobi-Bellman (HJB) equations and recursive numerical methods are applied to solve such equations.

Findings

The proposed approach led to determine more realistic production rates of both parts and setup sequences for the different modes of the machine that significantly influence the inventory and the system capacity. A numerical example and sensitivity analysis are used to determine the structure of the optimal policies and to show the helpfulness and robustness of the results obtained.

Practical implications

Following the steps of the proposed approach will provide the control policies for industrial manufacturing systems with setup permitted at all modes of the machine, and when the setup does not necessarily restore the machine to its operational mode. The proposed optimal policy takes into account the stochastic nature of the machine mode at the end of setup and we show that ignoring it leads to non-natural policies and underestimates significantly the safety stock thresholds.

Originality/value

Considering the assumptions presented in this paper leads to a new structure of the control laws for the production planning of manufacturing systems with setup.

Details

Journal of Quality in Maintenance Engineering, vol. 24 no. 2
Type: Research Article
ISSN: 1355-2511

Keywords

To view the access options for this content please click here
Article
Publication date: 16 August 2011

Achille N. Njike, Robert Pellerin and Jean Pierre Kenne

This paper seeks to develop an optimal stochastic control model where interactive feedback consists of the quantity of flawless and defective products. The main objective…

Abstract

Purpose

This paper seeks to develop an optimal stochastic control model where interactive feedback consists of the quantity of flawless and defective products. The main objective of this study is to minimize the expected discounted overall cost due to maintenance activities, inventory holding and backlogs.

Design/methodology/approach

The model differs from similar research projects in that, instead of age‐dependent machine failure, it considers only defective products as feedback into the optimal model for maintenance and production planning. In this paper a near optimal control policy of the system through numerical techniques is obtained.

Findings

In this paper, a new model in which the system's retroaction is the quantity of defective products is presented, considering that defective products are a consequence of global manufacturing system deterioration. Instead of taking into account machine failure and human error separately, it considers a defect in product as being the consequence of a combined failure; this consideration allows one to be more realistic by merging all failure parameters into a single one. A new stochastic control model, which focuses on defective products, inventory, and backlog, has been developed.

Research limitations/implications

This approach extended the concept of hedging point policy to the quantity of defective products combined with preventive and corrective maintenance strategies. The control policy obtained has a bang bang structure and is completely known for given parameters.

Originality/value

The integration of maintenance and production strategies has been mainly focused on the machine. Many research projects have been focusing on the age when dealing with machine failure. It is considered as the main target of the cost reduction in maintenance engineering departments. The originality of this paper is the taking into account of all operational failures into the same optimization model. It brings a value added to high level of maintenance and for operation managers who need to consider all failure parameters before taking decisions related to cost.

Details

Journal of Quality in Maintenance Engineering, vol. 17 no. 3
Type: Research Article
ISSN: 1355-2511

Keywords

To view the access options for this content please click here
Article
Publication date: 23 November 2010

Xudong Zhao and Qingshuang Zeng

As a class of stochastic hybrid systems, Markovian jump systems have been extensively studied in the past decades. In light of some results obtained on this topic. The…

Abstract

Purpose

As a class of stochastic hybrid systems, Markovian jump systems have been extensively studied in the past decades. In light of some results obtained on this topic. The purpose of this paper is to investigate the stability problems for delayed Markovian jump systems.

Design/methodology/approach

The time‐varying‐delays considered in this paper are switched synchronously with system mode. Based on stochastic Lyapunov theory, the delay‐dependent stability conditions are developed by using some linear matrix inequality techniques. To obtain better stability criteria, the different Lyapunov‐Krasovskii functional is chosen and an important inequality is introduced.

Findings

Numerical examples show that the resulting criteria in this paper have advantages over some previous ones in that they involve fewer matrix variables, but have less conservatism. Furthermore, they only involve the matrix variables appeared in the Lyapunov functional. Therefore, there are no additional matrix variables coupled with the system matrices, which will be easier to investigate the synthesis problems for the underlying systems and save much computation.

Originality/value

The introduced approach is more efficient to investigate the stability for Markovian jump systems with mode‐dependent time‐varying‐delays.

Details

International Journal of Intelligent Computing and Cybernetics, vol. 3 no. 4
Type: Research Article
ISSN: 1756-378X

Keywords

To view the access options for this content please click here
Article
Publication date: 15 August 2008

Allen S.B. Tam and John W.H. Price

Asset maintenance activities need to be prioritised as budget and planned outage time is often limited for all maintenance work to be carried out. The purpose of this…

Abstract

Purpose

Asset maintenance activities need to be prioritised as budget and planned outage time is often limited for all maintenance work to be carried out. The purpose of this paper is to develop a technique for prioritising maintenance work that maximises the return on investment under the constraints of budget and time.

Design/methodology/approach

Three indices are proposed to be used as indicators for prioritising maintenance. These indices are termed: maintenance investment index (MII), time index (TI) and budgetary index (BI). These indices permit prioritisation of asset maintenance based on the required emphasis on return on maintenance investment, time and budget respectively.

Findings

It is found that approaches to prioritising maintenance which integrate the critical dimensions in the decision making process are lacking in the literature. There is a need for such an approach to assist decision makers to ensure enterprise's objectives and targets are maximised with given budget and planned shutdown time.

Practical implications

The proposed techniques will assist engineers and mangers to develop their maintenance plan according to the enterprise needs and constraints and allowing management to make a better informed decision in maintenance.

Originality/value

This paper provides a new technique for ranking maintenance that maximises return on investment.

Details

Journal of Quality in Maintenance Engineering, vol. 14 no. 3
Type: Research Article
ISSN: 1355-2511

Keywords

To view the access options for this content please click here
Article
Publication date: 1 March 2005

S.A. Oke

The paper presents a mathematical model that measures the profitability of the maintenance system based on the traditional accounting definition of profitability. There is…

Abstract

Purpose

The paper presents a mathematical model that measures the profitability of the maintenance system based on the traditional accounting definition of profitability. There is currently a dire need for an article presenting a scientific‐based framework for practitioners in maintenance to make optimal instead of sub‐optimal decisions on profitability. Design/methodology/approach – A case study is presented to reflect the actual application of the proposed model. Different situations were considered in modelling to obtain optimal results. Simulation experiments were conducted to demonstrate that maintenance profitability is a reality through the use of differential calculus. Findings – It was observed that the approach presented is a holistic viewpoint of maintenance profitability measurement. Research limitations/implications – An adequate understanding of the maintenance system is needed to properly implement the model. Practical implications – The practical application of the model is that the maintenance system will now be viewed as a value‐adding activity instead of “a necessary evil” or “a bottomless pit for expenses”. Originality/value – This paper fulfils an identified need and offers practical help to managers in taking guided decisions that are optimal.

Details

International Journal of Productivity and Performance Management, vol. 54 no. 2
Type: Research Article
ISSN: 1741-0401

Keywords

To view the access options for this content please click here
Article
Publication date: 7 October 2014

Behnam Emami-Mehrgani, Sylvie Nadeau and Jean-Pierre Kenné

The analysis of the optimal production and preventive maintenance with lockout/tagout planning problem for a manufacturing system is presented in this paper. The…

Abstract

Purpose

The analysis of the optimal production and preventive maintenance with lockout/tagout planning problem for a manufacturing system is presented in this paper. The considered manufacturing system consists of two non-identical machines in passive redundancy producing one type of part. These machines are subject to random breakdowns and repairs. The purpose of this paper is to minimize production, inventory, backlog and maintenance costs over an infinite planning horizon; in addition, it aims to verify the influence of human reliability on the inventory levels for illustrating the importance of human error during the maintenance and lockout/tagout activities.

Design/methodology/approach

This paper is different compared to other research projects on preventive maintenance and lockout/tagout. The influence of human error on lockout/tagout as well as on preventive maintenance activities are presented in this paper. The preventive maintenance policy depends on the machine age. For the considered manufacturing system the optimality conditions are provided, and numerical methods are used to obtain machine age-dependent optimal control policies (production and preventive maintenance rates with lockout/tagout). Numerical examples and sensitivity analysis are presented to illustrate the usefulness of the proposed approach. The system capacity is described by a finite-state Markov chain.

Findings

The proposed model taking into account the preventive maintenance activities with lockout/tagout and human error jointly, instead of taking into account separately. It verifies the influence of human error during preventive maintenance and lockout/tagout activities on the optimal safety stock levels using an extension of the hedging point structure.

Practical implications

The model proposed in this paper might be extended to manufacturing systems, but a number of conditions must be met to make effective use of it.

Originality/value

The originality of this paper is to consider the preventive maintenance activities with lockout/tagout and human error simultaneously. The control policy is obtained in order to find the solution for the considered manufacturing system. This paper also brings a new vision on the importance of human reliability during preventive maintenance and lockout/tagout activities.

Details

Journal of Quality in Maintenance Engineering, vol. 20 no. 4
Type: Research Article
ISSN: 1355-2511

Keywords

To view the access options for this content please click here
Article
Publication date: 14 May 2020

Nouhayla Hafidi, Abdellah El Barkany, Abderrahman EL Mhamedi and Morad Mahmoudi

The purpose of this paper is to consider various possible constraints of the problem of production and maintenance planning control for a multi-machine under…

Abstract

Purpose

The purpose of this paper is to consider various possible constraints of the problem of production and maintenance planning control for a multi-machine under subcontracting constraint, in order to bring the manufacturer industry closer to real mode. In this paper, we present an efficient and feasible optimal solution, by comparing optimization procedures.

Design/methodology/approach

Our manufacturing system is composed of parallel machines producing a single product, to satisfy a random demand under a given service level. In fact, the demand is greater than the total capacity of the set of machines; hence there rises a necessity of subcontracting to complete the missing demand. In addition, we consider that the unit cost of subcontracting is a variable depending on the quantity subcontracted. As a result, we have developed a stochastic optimal control model. Then, to solve the problem we compared three optimization methods: (exact/approximate), the genetic algorithm (GA), the Pattern Search (PS) and finally fmincon. Thus, we validate our approach via a numerical example and a sensitivity analysis.

Findings

This paper defines an internal production plan, a subcontracting plan and an optimal maintenance strategy. The optimal solution presented in this paper significantly improves the ability of the decision maker to consider larger instances of the integrated model. In addition, the decision maker can answer the following question: Which is the most optimal subcontractor to choose?

Practical implications

The approach developed deals with the case of the real-mode manufacturing industry, taking into consideration different constraints and determining decision variables which allow it to expand the profits of the manufacturing industry in different domains such as automotive, aeronautics, textile and pharmacies.

Originality/value

This paper is one of the few documents dealing with the integrated maintenance in subcontracting constraint production which considers the complex aspect of the multi-machine manufacturing industry. We also dealt with the stochastic aspect of demand and failures. Then, we covered the impact of the unit cost variation of subcontracting on the total cost. Finally, we shed light on a comparison between three optimization methods in order to arrive at the most optimal solution.

Details

Journal of Quality in Maintenance Engineering, vol. 27 no. 1
Type: Research Article
ISSN: 1355-2511

Keywords

To view the access options for this content please click here
Article
Publication date: 16 August 2011

Gilles Cormier and Nidhal Rezg

The purpose of this study is to gain some insights into the number of shortages resulting from two alternative demand allocation schemes between a contractor (machine M1

Abstract

Purpose

The purpose of this study is to gain some insights into the number of shortages resulting from two alternative demand allocation schemes between a contractor (machine M1) and subcontractor (machine M2), on the one hand, and from inventory accumulation, on the other hand. The shortages stem from random machine breakdowns, and each machine undergoes preventive maintenance. The motivation behind inventory accumulation is to allow demand to be fulfilled even when both machines are down.

Design/methodology/approach

The number of shortages stemming from all scenarios under consideration was established via computer simulation with the Arena© language.

Findings

For demand allocation that remains unchanged for the duration of the planning horizon and constant reliability of M1, it was found that, the less reliable M2 is, the more biased in favour of M1 will be the optimal demand allocation and the greater will be the number of shortages. Moreover, both dynamic demand reallocation over the planning horizon and inventory accumulation result in a substantial reduction in shortages.

Research limitations/implications

The results are representative of the specific data, which were assumed in the simulation models. Nevertheless, this methodology is recommended for this type of analysis, as it is highly flexible and can take into account many practical considerations, which an analytical approach cannot.

Practical implications

Within the context of unreliable production machines, the most important practical implication of this study is that the dynamic reallocation of demand between a contractor and subcontractor, along with inventory accumulation, both have the potential to yield important reductions in the number of shortages.

Originality/value

The subject‐matter of this paper was not previously reported in the literature. Furthermore, the insights gained as a result of this study can yield substantial benefits to companies in terms of improving their service levels as measured by reduced shortages.

Details

Journal of Quality in Maintenance Engineering, vol. 17 no. 3
Type: Research Article
ISSN: 1355-2511

Keywords

1 – 10 of 50