PANG Sheng(龐 升), JIA Yun-xian(賈云獻(xiàn)), LI Xin-yue(李欣玥), DENG Ya-chong(鄧雅沖)

Department of Equipment Command and Management, Mechanical Engineering College, Shijiazhuang 050003, China

Equipment Maintenance Mode Based on Network Environment

PANG Sheng(龐 升), JIA Yun-xian(賈云獻(xiàn)), LI Xin-yue(李欣玥), DENG Ya-chong(鄧雅沖)

DepartmentofEquipmentCommandandManagement,MechanicalEngineeringCollege,Shijiazhuang050003,China

Aimed at the actuality of Peoplep’s Liberation Army (PLA) army equipment maintenance, this paper develops equipment maintenance mode based on network, and focuses on the design of maintenance decision-making system. Analyzing maintenance weight is applied to making decision of repair level. The purpose of the research is introducing basic concept and setting up an equipment maintenance mode using military network. Maintenance mode based on network can reduce the costs, enhance the maintenance efficiency, and save the human resource and finance.

equipmentmaintenance;failurediagnose;maintenancedecision-making;network

Introduction

With the rapid development in science and technology, weapon equipments are designed to be more and more automated, complicated, and intelligent. Consequently, maintenance is becoming more and more complex and having to cope with higher technical and battle expectations. Therefore, traditional maintenance mode and methods have not geared to equipment development, and the deficiencies are as follows. Firstly, the efficiency of failure diagnose and maintenance have been restricted by human, technology and regions in a certain extent. Secondly, the level of maintenance have been restricted because of unshared information coming from failure diagnose and maintenance resource. Thirdly, the information of damaged equipment has not been rapidly and accurately transmitted to maintenance person in battlefield. Fourthly, the team of maintenance human has too much redundancy, organization structuring is complicated and the costs of maintenance are relatively high[1].

The studies of many papers are based on traditional maintenance mode, and the methods of failure diagnose are usually behind the times. Maintenance decision-making has been done at random, so the phenomenon still approximately exists in these studies due to localization of this traditional maintenance mode.

With the rapid development in network, a method which weapon equipment maintenance and failure diagnose making use of network resource has attracted people’s attention. This method has overcome various handicap of traditional maintenance in resource, methods and spot[2]. At the same time, the costs have been reduced, and maintenance efficiency has been enhanced, as well as savings in manpower, material and physical resouces.

1 Essential Principle

Because the traditional maintenance mode still exists limitations, we develop a new maintenance mode based on network. This mode provides maintenance service in equipment lifecycle, including information management, basic design/manufacture parameter, monitoring track of operational state, immediate maintenance, rapid diagnose of intelligent of weapon equipment and many other aspects[3]. Computers are the core of this system. Advanced technology including network, database, expert system, multimedia, network communication and so on, is organically integrated with modern equipment management to set up a failure diagnose and maintenance service system based on network.

This maintenance mode is established based on the data collection/disposal subsystem, long-distance failure diagnose subsystem, maintenance decision-making subsystem. At the same time, the network subsystems are independent with each other and integrated into an organic system to actualize battle, maintenance and formulate scheme which can be executed on different spots[4]. The system can also meet the need of rapid settlement of equipment maintenance in peacetime and rapid decision-making of equipment maintenance in wartime[5].

The steps of the practical operational method are as follows. Firstly, data collection/disposal subsystem is in charge of collecting and disposing information of damaged equipment and transmitting these data to network. Secondly, long-distance failure diagnose subsystem provides diagnose environment, network communication subsystem monitor maintenance process timely. Thirdly, maintenance decision-making subsystem analyzes the data of damaged equipment, works out maintenance policy, and guides maintenance organization to complete maintenance of damaged equipment through network communication subsystem. The maintenance flow can be seen in Fig.1.

Fig.1 Equipment maintenance logic diagram based on network

2 Subsystem Function

2.1 Data collection/disposal subsystem

In order to make the network maintenance decision, the data of damaged equipment such as temperature and vibration, should be transmitted to decision-maker. The data collected from various sensors and testing equipment are treated in data collection/disposal computer to enhance their signal intensity, filter disturbing signal, and transform their format by putting into code. Then they are transmitted to equipment maintenance database through military network. If it is difficult to collect signal or the equipment is grievously damaged, the operational state data can be artificially collected through personal digital assistant (PDA). Then these data could be transmitted to decision-making system as soon as possible.

2.2 Long-distance failure diagnose subsystem

The functions of this subsystem include video conference, long-distance direct dialogue, and direct transmission of the damaged information. This subsystem can help the maintenance experts and technicians in different places to make maintenance decision together, who don’t have to be in the battlefield. And the data produced from this subsystem would be transmitted into the maintenance decision-making subsystem to make right maintenance decisions.

The failure of subsystem monitor can be easily discovered and repaired on the spot. Consequently, its failure diagnose module mainly considers analyses and judgments of the structural question. On the bases of statistic and category, all types of equipment fault tree can be built, and fault tree analysis (FTA) can be a method to diagnose failures.

FTA usually connects failure phenomenon with failure reason. Long-distance failure diagnose subsystem includes failure phenomenon information and failure reason information, and theirs corresponding database are failure phenomenon table and failure disposal information table. Failure phenomenon information is depicted by means of hierarchy. And it can be divided into father-phenomenon, firstly son-phenomen on, secondary son-phenomenon, and so on. The results exist in drawing one by one comparisons between failure phenomenon imported by repairer and failure phenomenon information in computer.

Failure disposal information table provides failure depict and disposal method, primary offer decision-making support of this failure to repairer, and choose on-site repair or evacuation repair, which maintenance level will really send,etc. Long-distance failure diagnose function can be came true by integrating failure disposal information table with failure phenomenon information.

As shown in Fig.2, failure phenomena are input through human-machine interaction interface of web browse by repairer, and transmitted to web server. Web server judges where is failure exist according to the failure phenomenon information received, then the repairer obtains maintenance advice or concept according to failure disposal information. If repairer can’t find solution, failure can be located and evaluated through long-distance guidance, failure phenomena can be transmitted to the maintenance decision-making subsystem by means of audio frequency or video frequency. And then the failure place is located, the failure reason is found, and the maintenance policy is made.

Fig.2 The process of long-distance failure diagnose subsystem

2.3 Maintenance decision-making subsystem

Maintenance decision-making subsystem is the core of this system, and can be generally divided into three parts, maintenance mode decision-making, level of repair decision-making and maintenance technical decision-making.

2.3.1 Maintenance mode decision-making

Maintenance mode decision-making model could estimate damaged information and confirmed maintenance mode rapidly,e.g., evacuation repair, battlefield damaged assessment repair (BDAR), restoration survivability maintenance (RSM), and condition-based maintenance (CBM)[6]. In the course of maintenance mode decision-making, the maintenance weight value needs to be thought over firstly if the decision makers want to use computer. Compared the set value with threshold, the requisite maintenance mode can be confirmed. The process of maintenance mode decision-making is shown in Fig.3.

Fig.3 The process of maintenance mode decision-making

Maintenance weight reflects the importance of equipment parts in the course of decision-making. It can be assessed according to function, significance, maintenance, economics and measurability of equipment parts in battlefield. The numerical value of maintenance weight is limited to [0, 1][4]. When the value is nearer to 1, the equipment parts are more important; on the contrary, if the value is nearer to 0, the weight is less important.

There are many methods in weight calculation, like expert method, binomial coefficient method, parallelism method, and least squares method, expert method and binomial coefficient method, and the latter two are introduced in this paper.

Expert method: the numerical value of each equipment parts is directly confirmed by many equipment maintenance experts, the authorities from equipment design department and the workers from equipment manufacture. This arithmetic depend completely on experience of experts, and the set value is directly input into maintenance decision-making database[7].

Binomial coefficient method: each maintenance decision-making object is arranged according to their importance. That is, the most important object is put on the first place, the second important is put on the last place, and so on, as shown in Eq. (1)[7].

(1)

whereλirepresents the weight of theith object arranged over again,mrepresents sum of object.

2.3.2 Level of repair decision-making

According to the evaluation results of un-repaired equipment’s operation and examination parameter, the level of repair decision-making can make a conclusion which includes overhaul, repair or discard, The damaged degree, namely, the war condition of equipment deviates from good condition and develops to invalidate condition, is confirmed firstly. The actual measured value of damaged degree is very important to the level of repair decision-making. And both the deviation degree from good condition and the approach degree to limit invalidate condition are considered. The computational process can be seen in Eq. (2).

Li=[(C-A)/(B-A)]K,

(2)

whereLirepresents damaged degree of theith parameter,Arepresents the manufacture permissible value of this parameter,Brepresents the limit invalidate condition value of this parameter,Crepresents the actual measured value of this parameter, andKrepresents the weight in wartime of this parameter. AndKreflects the importance of this equipment part in course of battle, which generally equals 2[7].

The value of damaged degree reflects equipment damaged condition. When it is close to 0, the availability of equipment parts is higher. On the contrary, if it is nearer to 1, the equipment part is seriously damaged. The level of repair is confirmed through a comparison between the damaged degree and the set value. The set value can be constantly searched through maintenance practice.

2.3.3 Maintenance technical decision-making

Maintenance technical decision-making is an optimization working procedure to decide time, cost, and material after the level of repair in overhauls, repair and service. The maintenance decision-making subsystem can provide decision-making support service. As maintenance encounter numerous obstacles in peacetime, maintenance concept can be drawn by decision-making system or directly dialogue with experts. At the same time, the repairer can consult maintenance cases of the same type in this database. The process of maintenance decision-making in wartime can be seen in Fig.4.

Fig.4 The process of maintenance decision-making in wartime

2.4 Database management subsystem

Database is necessary to realize intelligence of maintenance decision-making, including the technical information data which come from design and manufacture department[8], the maintenance information data which come from maintenance management department, the mode/ level/ technical data which come from expert, and the data of decision-making support.

2.4.1 Technical information data

The data is composed of a series of original data,e.g., technical parameter, design drawing, material capability, connection, assembly, lubrication, fastness, and seal. Those data are essential in maintenance.

2.4.2 Maintenance information data

The data are composed of the routines management information (using time, overhauls, repair, service and curriculum vitae) of whole equipment and the run and maintenance state of each part. This data plays an assistant role in maintenance decision-making and repair in peacetime.

2.4.3 Expert system

The data are composed of systemic and intellective experience which come from maintenance expert and support expert, and can be come into theory system guiding maintenance activity[9]. The problem in repair process can be settled to consult expert system. This system possessed not only qualitative function, but also quantitative calculator function.

2.4.4 Decision-making support model data

The data are composed of failure analysis model, failure forecast model, maintenance interval decision-making model, maintenance mode evaluation standard and level of repair evaluation standard. The maintenance model is developed according to maintenance information and damaged condition of equipment. For common damaged equipment, maintenance concept can be produced through applications of this model. This database is the foundation of quick response in BDAR and maintenance concept drawing. To build the database is one of difficulties of this system. It needs a lot of human and resource. However, if the database is set up successfully, it will bring great convenience to find up data for maintenance organizations.

2.5 Network communication subsystem

The picture, video frequency and various signal of damaged equipment, as the first-hand information to the decision-making, collected on battlefield are transmitted to the decision-making computer through military network[10]. The exact, swift and safe transmission of the necessary and sufficient maintenance information will exert a direct effect on the validity and speediness of decision-making.

2.6 Network safety subsystem

Firewall technique and identifying code are integrative applied in this system. The filtration router should check every IP address to judge whether it is allowed to visit or not. The internal member don’t allow visit without identifying code. In order to avoid leak secret, the user name and the pass code are kept secret. The high-grade data can be enacted to visiting limitation according to secrecy levels.

3 Conclusions

The paper sets up a maintenance mode based on network and computer technology, and describes the elements and functions of every subsystem in detail. Then the maintenance process is proposed. At present, maintenance based on network is a new development trend. Various equipments has distributed, it will bring more difficulties to make decision. In future studies, how to improve efficiency of failure diagnose and complete maintenance system will be attended.

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N945 Document code: A

1672-5220(2015)01-0171-04

Received date: 2014- 08- 08

* Correspondence should be addressed to PANG Sheng, E-mail: 642493180@qq.com