Design and Development of a Maintenance Knowledge- Base System Based on CommonKADS Methodology Alireza Arab Maki Navid Shariat Zadeh Master Thesis Department Production Engineering and Management School of Industrial Engineering and Management Royal Institute of Technology SE-10044 Stockholm, Sweden June 2010 Abstract The objective of this thesis is to design and develop a knowledge base model to support the maintenance system structure. The aim of this model is to identify the failure modes which are the heart of maintenance system through the functional analysis and then serves as a decision support system to define the maintenance tasks and finally to implement a preventive maintenance task. This knowledge base management system is suitable to design and develop maintenance system since it encompasses all necessary steps in maintenance area. Moreover, it is capable of being integrated with other knowledge base systems. The structure and the environment of this knowledge base system is flexible to allow users to deploy different kinds of tools which they will. It is also a well structured approach to develop, debug, upgrade and trace. In this thesis, the CommonKADS methodology is used as the knowledge base methodology. At the first step, a knowledge base system is developed to create the maintenance system infrastructure. To implement this, Reliability-Centered Maintenance (RCM) has been chosen as the method to design a maintenance system. In order to make it more specified, a Spindle subsystem is taken as a case study to make the model clearer. Secondly, another knowledge base system is developed for decision making process to select the suitable maintenance task and finally, a general knowledge base model is developed for condition-based monitoring on Spindle. In chapter 1, background, previous works and gap analysis have been surveyed. Then in chapter 2 the methodology and tools have been discussed and described. Design and development the knowledge base for maintenance system is described in detail in chapter 3 and finally in chapter 4, the conclusion and the future works are presented. Keywords: Knowledge base systems, CommonKADS methodology, Maintenance, Condition- based Monitoring (CBM), Reliability-Centered Maintenance (RCM) Acknowledgement During the work with this thesis, we have received a lot of help from Mr. Jerzy Mikler as our thesis supervisor. We would like to express our sincere gratitude to him. Also we would like to thanks the officials of Production Engineering and Management department for preparing appropriate environment to work and research. We want to thank our parents for their financial and never ending support, for the help in our studies and for its success. Alireza Arab Maki and Navid Shariat Zadeh Stockholm, June 2010 Table of Contents Chapter 1 – Introduction 1 Introduction …………………………...…………………………………………... 2 1.1 Background ……………………………………………………………………...... 2 1.2 Previous Researches …………………..…………………………………………... 3 1.2.1 Condition-Based Monitoring ……………………………………………………... 3 1.2.2 CBM using Neural Network ………….…………………………………………... 5 1.2.3 CBM using Bayesian Network ……….…………………………………………... 7 1.3 Gap Analysis ………………………….…………………………………………... 10 1.4 Thesis Objectives ……………………..…………………………………………... 11 1.5 Delimitation …………………………..…………………………………………... 11 Chapter 2 – Methodology and Tools 2 Methodology and Tools …………………………………………………………... 13 2.1 The Methodology ……………………..…………………………………………... 13 2.1.1 Model Structure …………………………………………………………………... 13 2.1.2 Some Terminology ………………………………………………………………... 16 2.1.3 Organizational Model ………………...…………………………………………... 16 2.1.4 Impact and Improvement Analysis: Task and Agent Modelling …………..……... 19 2.1.5 Recommendations and Actions ……….…………………………………………... 23 2.1.6 Knowledge Model …………………….…………………………………………... 23 2.1.6.1 Role of Knowledge Model ………………………………………………………... 23 2.1.6.2 Knowledge Model Overview ……………………………………………………... 23 2.1.6.2.1 Domain Knowledge …………………..…………………………………………... 24 2.1.6.2.2 Inference Knowledge ……………………………………………………………... 25 2.1.6.2.3 Task Knowledge ……………………………...…………………………………... 25 2.2 Reliability-Centered Maintenance (RCM) ………………………………………... 27 2.2.1 Background …………………………...…………………………………………... 27 2.2.2 Functions ……………………………...…………………………………………... 28 2.2.3 Functional Failure …………………….…………………………………………... 28 2.2.4 Failure Modes ………………………...…………………………………………... 28 2.2.5 Symptoms and Consequences …….…………………..…………………………... 28 2.2.6 Failure Management Techniques ……..…………………………………………... 29 2.2.7 Task Selection Process ………………..…………………………………………... 29 2.3 Integrated Condition Monitoring and Fault Prognosis .…………………………... 31 2.3.1 Measurable Parameters ……………….…………………………………………... 32 2.3.2 Selection of Proper CBM Equipment ...…………………………………………... 32 2.3.2.1 Energized Testing …………………….…………………………………………... 32 2.3.3 The System to Analyze the Collected Data ..……………………………………... 33 2.4 CUSUM Control Charts …………………………………………………………... 33 2.4.1 Description ………………………………………………………………………... 34 Chapter 3 - Design and Develop the Knowledge Base for Maintenance System 3 Design and Develop the Knowledge Base for Maintenance System ……………... 36 3.1 General Description …………………..…………………………………………... 36 3.2 Organization Model Analysis ………...…………………………………………... 36 3.3 Knowledge Intensive Task Model Analysis ………….…………………………... 39 3.3.1 Task 2 - Analyze the Machinery and Determine the Failure Modes ……………... 39 3.3.2 Task 3 - Realizing the Maintenance Task .………………………………………... 54 3.3.3 Task 5 – Implementation Of Preventive Maintenance Task .……………………... 61 Chapter 4 - Conclusion and Future Works 4 Conclusion and Future Works ………..…………………………………………... 86 4.1 Conclusion ………………………………………………………………………... 86 4.2 Future Works ……………………………………………………………………... 86 Appendix A – FMEA of Spindle System …...….………………………………………... 87 References …………………………………………..………………………………………... 89 Chapter 1 Introduction 1 Chapter 1 – Introduction 1 Introduction 1.1 Background In order to run a successful manufacturing company, continuous improvement must be considered and implemented in the areas of safety, quality and reliability. To achieve this, one of the most important processes which must be subject of improvement is maintenance process. Improvement of safety, quality, reliability and dependability in a plant is directly associated to the maintenance system in a company. Amelioration in these areas will result in cost reduction and more internal and external customer satisfaction which helps to create a competitive market. Moreover, it has been proved that the maintenance cost is one of the main parts of life cycle cost of a product or asset. There are two main types of maintenance task: - Corrective maintenance : The strategy behind this approach is to let the equipment fail (also called run to failure) and then start to cover the damaged equipment. This approach is suitable just in case that the equipments’ failures’ consequences are not neither safety nor environmental. - Preventive maintenance : The strategy behind this approach is to maintain the equipment before the failure occurs. This approach has two main methods like time- based maintenance and condition-based monitoring. This approach is suitable when an unplanned stoppage of the equipment result in high equipment downtime, high cost of repairing equipment, extensive repair time and high penalty associated with the loss of production which all decrease the effectiveness and efficiency of the factory dramatically. Nowadays, the question is that how to design a maintenance system and make a decision about the suitable maintenance strategy. There are many methods to achieve the mentioned purpose. Failure Mode and Effect Analysis (FMEA) has been used to analyze all the possible failure modes. Statistical analysis using the historical data has been used for time-based maintenance and recently thanks to the technological improvement in the areas of sensors, data capturing and analysis software and hardware; many plants utilize computer control systems for condition-based monitoring of their equipments. Also, Reliability-Centered Maintenance (RCM) technique has been adopted as a strong method to analyze the functions, functional failures, failure mode and consequences. This technique includes decision rules to determine different maintenance tasks such as redesign, run to failure, scheduled restoration, etc. 2 Implementation and application of such method for maintenance result in generating huge amount of data, information and knowledge which must be managed in a proper way. This information management must contain generating, storing, analyzing and dispatching the data among whole process. The main works which are done in this area are briefly presented in next section (1.2) however; the lack of a well-structured comprehensive model to design and implement a maintenance management system is noticed. Therefore, the aim of this thesis is to design a knowledge base management system in maintenance area which encompasses necessary tasks in the areas such as failure mode analysis, maintenance task decision making and finally supporting the implementation of selected task. To achieve this goal, the following methodology, techniques and assumption are used in this thesis: CommonKADS Methodology: This methodology is used to deal with the knowledge base management and it is described in Chapter 2. The reasons to choose this methodology are: - Gradually extension of the methodology as a result of feedback from practitioner and scientists over the years, - It is not a technology-push