Abstract:
Methods of providing maintenance management of a machine are disclosed. In one embodiment, the method involves identifying a machine component failure that, if not repaired, will result in a functional failure of the machine. A criticality factor is assigned to the machine component failure based on at least a probability of occurrence of the functional failure and a consequence of the functional failure to a machine user. A maintenance task is generated to repair the machine component failure, and a triggering condition that activates the maintenance task is defined. The method further involves conducting a machine repair in response to a detection of the triggering condition, and maintaining a record that includes information relating to the conducted machine repair. The method of providing maintenance management is also modified based on at least the record.

Description:
TECHNICAL FIELD 
   The present disclosure relates generally to maintenance management, and more particularly to a method of managing maintenance of a machine. 
   BACKGROUND 
   The profitability of an organization that utilizes machines in its operation is dependent on its ability to effectively maintain the machines in a manner that optimizes their reliability and performance. For instance, the profitability of an organization that provides maintenance service for machinery through long-term maintenance contracts relies on its ability to maintain the machines in good working order at the lowest cost. The importance of an efficient maintenance management approach become all the more important when numerous machines have to be maintained in various geographic sites around the world. Currently, maintenance of such machines are performed in an ad-hoc manner and the performance of each service contract is reliant on the experience and expertise of specific contract management personnel, resulting in varying performances for different service contracts. 
   U.S. Pat. No. 6,836,539 (the &#39;539 patent) to Katou et al. describes a machine maintenance management method to quickly and accurately repair machines that operate at remote locations under severe conditions. The method of the &#39;539 patent uses an electronic control unit (ECU) attached to the machine to monitor an operating condition of the machine. The monitored operating condition is then transmitted to a monitoring facility. When the monitored operating condition indicates a failure of the machine, the ECU determines the cause of the failure and communicates repair instructions to repair personnel. The method of the &#39;539 patent further includes placing purchase orders for replacement parts to reduce down-time of the machine during repair. 
   Although the maintenance management method of the &#39;539 patent may reduce the time taken to repair a machine at a remote location, this method only addresses machine repair after a failure has occurred. The method of the &#39;539 patent does not provide for preventive maintenance of the machine to prevent a failure. Nor does the approach of the &#39;539 patent allow for monitoring of the machine operating condition to identify a condition where failure may be imminent, and facilitate repair of the machine before the failure actually occurs. Additionally, the approach of the &#39;539 patent may not be optimized to account for the challenges of simultaneous management of many maintenance contracts each comprising numerous machines. 
   The disclosed maintenance management system is directed to overcoming one or more of the problems set forth above. 
   SUMMARY OF THE INVENTION 
   In one aspect, the present disclosure is directed to a method of providing maintenance management of a machine. The method involves identifying a machine component failure that, if not repaired, will result in a functional failure of the machine. A criticality factor is assigned to the machine component failure based on at least a probability of occurrence of the functional failure and a consequence of the functional failure to a machine user. A maintenance task is generated to repair the machine component failure, and a triggering condition that activates the maintenance task is defined. The method further involves conducting a machine repair in response to a detection of the triggering condition, and maintaining a record that includes information relating to the conducted machine repair. The method of providing maintenance management is also modified based on at least the record. 
   In another aspect, the present disclosure is directed to a method of providing maintenance management of a machine. The method involves classifying a machine failure as a critical failure or a non-critical failure based on at least a potential effect of the machine failure on a machine user and a probability of the machine failure, and identifying a critical failure of the machine based on an indicator reflecting a likelihood of the critical failure. The method also includes conducting a first machine maintenance before an occurrence of the critical failure, and conducting a second machine maintenance after an occurrence of the non-critical failure. The method further includes determining an effectiveness of at least one of the first machine maintenance and the second machine maintenance, and modifying the method of maintenance management based on the determined effectiveness. 
   In yet another aspect, the present disclosure is directed to a method of providing maintenance management of a machine. The method includes classifying a machine failure mode based on a criticality value, and developing a predictive maintenance task to repair the machine failure mode with the criticality value exceeding a predetermined value. The method also includes developing a preventive maintenance task to repair the machine failure mode with the criticality value exceeding a predetermined value, and developing a reactive maintenance task to repair the machine failure mode with the criticality value below a predetermined value. The method also involves executing one of the predictive maintenance task, the preventive maintenance task, or the reactive maintenance task on an occurrence of the failure mode, and maintaining a record that includes information related to the execution of the predictive maintenance task, the preventive maintenance task, or the reactive maintenance task. The method further includes calculating a performance metric based on the record. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic illustration of an exemplary maintenance management system consistent with certain disclosed embodiments; 
       FIG. 2  is a diagrammatic illustration of an exemplary maintenance management process for the system of  FIG. 1  consistent with certain disclosed embodiments; 
       FIG. 3  is a flowchart of an exemplary maintenance strategy development process of  FIG. 2  consistent with certain disclosed embodiments; 
       FIG. 4A  is a flowchart of an exemplary maintenance, materials, and personnel planning process for a preventive maintenance task defined in  FIG. 3  consistent with certain disclosed embodiments; 
       FIG. 4B  is a flowchart of an exemplary maintenance, materials, and personnel planning process for a predictive maintenance task defined in  FIG. 3  consistent with certain disclosed embodiments; 
       FIG. 4C  is a flowchart of an exemplary maintenance, materials, and personnel planning process for a reactive maintenance task defined in  FIG. 3  consistent with certain disclosed embodiments consistent with certain disclosed embodiments; 
       FIG. 5  is a flowchart of an exemplary plan execution and reporting process of  FIG. 2  consistent with certain disclosed embodiments; and 
       FIG. 6  is a flowchart of an exemplary maintenance method improvement process of  FIG. 2  consistent with certain disclosed embodiments. 
   

   DETAILED DESCRIPTION 
   Reference will now be made in detail to exemplary embodiments, which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts/steps. In the description that follows,  FIG. 1  will be used to describe a system for performing an embodiment of the disclosed maintenance management process for a machine, and  FIG. 2  will be used to provide a general overview of the maintenance management process.  FIGS. 3 through 6  will then describe the details of different steps involved in the process of  FIG. 2 . 
   A machine  4 , as the term is used herein, may include a fixed or mobile machine that performs some sort of operation associated with a particular industry, such as mining, construction, farming, power generation, etc. Non-limiting examples of a fixed machine may include turbines, power production systems, or engine systems operating in a plant or an off-shore environment. Non-limiting examples of a mobile machine may include trucks, cranes, earth moving vehicles, mining vehicles, backhoes, material handling equipment, marine vessels, aircraft, and any other type of movable machine that operates in a work environment. The term machine  4  also encompasses a plurality of similar or dissimilar machines, geographically located at the same or different places. For example, the term machine  4  may refer to a single fork-lift truck in a plant, a fleet of mining vehicles at a mine-site in Australia, a collection of turbines at various oil-fields around the world, or to a group encompassing the fork-lift truck, haul vehicles and the turbines. The location where a machine  4  operates will be referred to as a worksite  10 . The term worksite also encompasses a single or a plurality of locations where the machine  4  operates. A person who works with the machine  4  will be referred to as a machine user  6 . The machine user  6  may include an individual, group or a company that operates the machine  4 . The machine user  6  may also include personnel of a company or a group assigned the task of maintenance of the machine  4  (service contractor), and repair technicians who perform the maintenance. 
     FIG. 1  illustrates a maintenance management system  50  for performing maintenance management of a machine  4 . The machine  4  may be one of multiple machines that may be located at multiple worksites or at the same worksite  10 . The machine  4  may include one or more sensors  12  that measure some characteristic of the machine  4 . For instance, the machine  4  may include temperature sensors that detect the temperature at a location of the machine  4 . In some cases, the measured characteristic may indicate an incipient defect of the machine  4 . The sensors  12  may communicate the measured data of the machine  4  to a machine interface module  14 . The machine interface module  14  may include a computer system or other also data collection system. The communication of the data from the sensors  12  to the machine interface module  14  may be continuous or periodic, and may be accomplished through a wired connection or a wireless setup. The machine interface module  14  may be portable or fixed, and may be located proximate or remote to the machine  4 . 
   A machine user  6  may also input data into the machine interface module  14 . The data inputted by the machine user  6  may include data related to a status of the machine  4 . For instance, the data input by the machine user  6  may include data related to the daily operation of the machine  4 , the maintenance of machine  4 , or a defect observed on the machine  4 . The machine user  6  may electronically input the data (for instance, through an input device), or manually record the data (on one or more log books), which may then be input into the machine interface module  14 . 
   The machine interface module  14  may transmit data to a machine monitoring system  16 . The machine monitoring system  16  may include a computer system or a plurality of computer systems networked together. It is also contemplated that computers at different locations may be networked together to form the machine monitoring system  16 . The machine monitoring system  16  may include software configured to perform analysis, a database to store data and results of the analysis, a display device and/or an output device configured to output the data and the results to a machine user  6 . The data transmitted by the machine interface module  14  may include data measured by the sensors  12  and data recorded by the machine user  6 . This transmission of data to the machine monitoring system  16  may be continuous or periodic, and may be accomplished by any means known in the art. For instance, the data transmission may be accomplished using the word wide web, a wireless communication system, a wired connection, or by transferring a recording medium (flash memory, floppy disk, etc.) between the machine interface module  14  and the machine monitoring system  16 . The machine monitoring system  16  may be located proximate to the worksite  10  or may be situated in a remote location. The machine monitoring system  16  may be configured to record data from multiple machine interface modules  14  located at different geographic locations. In some instances, multiple machine interface modules  14  located in different continents may transmit data to a machine monitoring system  16 . It is also contemplated that in some cases, a separate machine interface module  14  may be eliminated and the sensor data and the machine user data may be input directly into the machine monitoring system  16 . The machine monitoring system  16  may perform analysis (using a software configured to do the analysis) on the data transmitted by the machine interface module  14  along with other data stored in the machine monitoring system  16 . The analysis may include any logic based operation on the data that produce some results. These results may include a maintenance schedule  18  of the machine  4  and reports  20  that may indicate the effectiveness the maintenance management plan. The machine monitoring system  16  may also be configured to automatically update other logistical planning systems, such as, for example, an inventory management system and/or a personnel scheduling system, based on the maintenance schedule  18 . The machine monitoring system  16  may also communicate data from multiple machine interface modules  14  to a management team  22 . 
   The management team  22  may be composed of machine users  6  responsible for managing the maintenance operation. The management team  22  may review information related to the data reported by one or more machine interface modules  14  along with other technical data  24  related to the maintenance of machine  4 . The technical data  24  may include historical maintenance information, machine user manuals, knowledge gained from previous experience and other machine technical information. The management team  22  may analyze the reviewed information and develop a maintenance plan for the machine  4 . This maintenance plan may be input into the machine monitoring system  16 . The management team  22  may also review the results (for example, the maintenance schedule  18  and the reports  20 ) produced by the machine monitoring system  16  to modify the maintenance plan. In some applications, the membership of the management team  22  that modifies the maintenance plan may be different than the membership of the management team  22  that develops the maintenance plan. 
     FIG. 2  depicts an overview of the maintenance management process  1000  that may be carried out by the maintenance management system  50  of  FIG. 1 . The maintenance management process  1000  may involve a maintenance strategy development process  100 . In the maintenance strategy development process  100 , the management team  22  may generate machine failure modes based on information of likely machine failures, worksite specific use conditions, and machine technical data  24 . In some applications, the machine monitoring system  16  may assist or may even automatically generate the failure modes for machine  4 . The machine failure modes may include a list of all potential failures that affect the functionality of the machine  4 . Worksite specific use conditions may include information on environmental and/or safety concerns and/or standards that may exist at a particular worksite  10 . The management team  22  may also assign a criticality factor to the generated failure modes. The criticality factor may include information on the level of importance the machine user  6  assigns to a particular machine  4 . For instance, information that a particular machine  4  is used as a backup machine, which can tolerate a few hours of planned down-time a week, may be used to assign a low criticality factor to the machine  4 . The output of the maintenance strategy development process  100  may include a maintenance plan for the machine  4 . 
   Following development of maintenance strategy for the machine  4 , the management team  22  may perform the maintenance, materials, and personnel planning process  200 . Maintenance planning may include development of maintenance procedures and plans for each failure mode identified in step  100 . For instance, maintenance planning may include determination of the frequency of a maintenance operation, such as, for example an oil change, and procedures to be followed for performing an oil change. The management team  22  may also determine the materials, tools, and personnel needed to perform the maintenance procedure at this stage. For instance, the spare parts and tools that will be needed to repair a certain failure, and the necessary skills needed for the repair may be determined. It is also contemplated, that in some cases, the machine monitoring system  16  may automatically develop the maintenance procedures and plans for a failure mode. This automatic development of maintenance procedures by the machine monitoring system  16  may be partly or wholly based on information of prior failures stored in a database of the machine monitoring system  16 . The management team  22  and/or the machine monitoring system  16  may also schedule tool time, and/or repair personnel time in the respective scheduling systems. 
   The maintenance plans developed by the management team  22  and/or the machine monitoring system  16  in step  200  may then be executed by the machine user  6  in step  400 . The machine user  6  may also report details of the execution to the machine interface module  14  (or to the machine monitoring system  16  directly in those embodiments without a machine interface module  14 ) in step  400 . For instance, the maintenance plan (developed in the maintenance strategy development step  100 ) may call for the replacement of an air filter of a machine  4  when the pressure drop across the air filter exceeds a pre-defined value. When sensors  12  indicate that the pressure drop across the filter exceeds the pre-defined value, the machine user  6  assigned to the maintenance task may execute the prescribed maintenance procedures for replacing the air filter (as defined by the management team  22  in step  200 ). Following the maintenance event, the machine user  6  may report the details of the repair conducted to the machine interface module  14 . The record may include specifics of the repair operation, such as the time taken to repair, machine down-time, cost incurred in the repair process, etc. The machine interface module  14  may transmit the record to the machine monitoring system  16 . In some cases, the machine interface module  14  may compile the records of multiple maintenance tasks and transmit the compiled record to the machine monitoring system  16 . The machine monitoring system  16  may create a report  20  summarizing details of execution of the maintenance plan. The report  20  may also include performance indicators that may indicate the health of the maintenance operation. The management team  22  may use these performance indicators to gauge the effectiveness of the maintenance management process  1000 . 
   The management team  22  may analyze the report  20  and modify the maintenance process in the maintenance method improvement process (step  600 ). The modifications to the maintenance management process  1000  may include changes to the defined failure modes, their criticality factors, classification of the maintenance tasks, the procedures used for a specific maintenance, and/or any other changes to improve the maintenance management process  1000 . It is also contemplated that performance indicators from one maintenance project may be used to modify the maintenance management process  1000  of another maintenance project. For instance, the performance indicators of a turbine maintenance project at one worksite  10  may indicate that the allowable pressure drop across a filter can be increased without adverse results. This information may be used to modify a turbine maintenance project at another worksite  10 . 
   The description above describes a general overview of the maintenance management process  1000 .  FIGS. 3 through 6  will now be used to further describe the details of the different steps involved in the maintenance management process  1000 . 
     FIG. 3  illustrates the steps involved in the maintenance strategy development process (step  100  of  FIG. 2 ). Development of the maintenance strategy may include a contextual review  110 . The management team  22  along with the machine monitoring system  16  may perform the contextual review  110 . During the contextual review  110 , the management team  22  may discuss the objectives for a maintenance project, along with any specific worksite related constraints. Information covered during the contextual review  110  may include, the operating philosophy of the machine user  6  and the maintenance contractor, machine availability requirements, machine use conditions describing the amount of time that a particular machine operates and the conditions under which it operates, criticality of the machine  4  to the machine user  6 , operational projections which may impact the use of the machine  4 , seasonal changes that may impact machine use and condition, environmental considerations (for e.g., local regulations that impact use of the machine), accountability during a maintenance event (for e.g., responsibility for support systems such as protective enclosures, etc.), maintenance schedule for other equipment in the worksite  10  (for e.g., how will the maintenance schedule of equipment not covered in a maintenance plan affect the maintenance schedule of a machine  4  covered in the plan), worksite constraints (for e.g., number of repair personnel allowed at one time, offshore versus onshore, etc.), performance requirements (for e.g., required response time for different failures, performance targets, training requirements, etc.), condition of the machine  4  (for e.g., machine age, review of prior maintenance records, etc.), and other information that may directly or peripherally impact the maintenance of the machine  4 . 
   Based on the contextual review  110 , the management team  22  or the machine monitoring system  16  may produce a requirements list (step  120 ). The requirements list may describe the key requirements and constraints of the maintenance project. For instance, the requirements list may assign a priority to a machine  4  based on the priorities of the machine user  6 . The requirements list may also include incentives/penalties for meeting/not meeting performance goals. 
   After the maintenance requirement list is created, the management team  22  and/or the machine monitoring system  16  may identify possible failure modes of the machine  4  (step  130 ). In some applications, the management team  22  along with machine experts may conduct a brainstorm session to identify the possible failure modes of the machine  4 . These machine experts may include representatives of the machine manufacturer and/or machine users  6  who have technical and/or practical knowledge of the machine. In other applications, the machine monitoring system  16  may automatically generate the failure modes for the machine  4 . For example, information from a maintenance project of a similar machine  4  at another worksite  10  stored in a database of the machine monitoring system  16  along with other machine related information may be used to automatically generate the possible failure modes of the machine  4 . It is also contemplated that the machine user  6  and the machine monitoring system  16  may also jointly identify the potential failure modes of the machine  4 . The process of identifying the failure modes may include performing a Reliability Centered Maintenance (RCM) analysis. RCM analysis is a process of systematically analyzing an machine  4  made up several components, to attribute the cause of each possible functional failure of the machine to one or more components. The general steps involved in the RCM analysis for a machine  4  may include, partitioning the machine  4  into components, and assigning the cause of each functional failure to one or more of these components. The RCM analysis may be conducted afresh for a project or it may be reused from another project. 
   To partition the machine  4  into components, the management team  22  may partition the machine  4  into different functional groups that define an operational characteristic of the machine  4 . For example, the management team  22  may partition a turbine into functional groups, such as electrical system, fuel system, gear box, lube oil system, etc., based on the function of the different groups. These functional groups may be further partitioned into components until a failure mode may be identified with each discrete component. For instance, the fuel system of the previous example may be further partitioned into several components such as supply lines, gas check transmitter, HI start Q switch, off skid block valve, torch gas system exciter, torch gas system igniter, torch gas system solenoid valve, etc. The management team  22  and the machine monitoring system  16  may also determine the probability of occurrence of each identified failure mode. These probabilities may be determined based on prior knowledge, equipment supplier data, or by other means. For example, maintenance data from another maintenance project of a similar machine  4 , stored in the database of the machine monitoring system  16  may be used to determine the probability of occurrence of the failure modes. A probability value may also be assigned to each failure mode based on the probability of its occurrence. In some cases, the probability value may be a numerical value that ranges between set values, such as from 1 to 5, with 1 indicating a low probability of occurrence and 5 indicating a high probability of occurrence. It is also contemplated that other probability representations may be implemented. 
   Once the potential failure modes have been identified and the probability of their occurrence determined, the next step is to understand the consequence of these failures (step  135 ) to the machine user  6 . The failure modes identified in step  130  may result in a functional failure of the machine  4 . The process of understanding the consequence of a failure mode (step  135 ) captures the effect of the functional failure to the machine user  6 . The management team  22  may use the information from contextual review  110  to understand the impact of a failure mode to the machine user  6 . Failure mode Effect and Criticality Analysis (FMECA) may be used to establish a cause and effect relationship among different failure modes and functional failure of the machine  4 . For example, an FMECA on a fuel system failure mode, such as, for example, the inability to regulate gas supply to a turbine (machine  4 ) during startup, may attribute this failure to a defect in some or all of the fuel system components, such as, for example, the gas check transmitter, HI start Q switch, and the off skid block valve. The management team  22  may also assign a consequence value to each failure mode to indicate the seriousness of the consequences of a failure mode. The consequence value may vary between a set range of values, such as a scale from 1 to 10 (1 being low and 10 being severe). It is also contemplated that other types of consequence values may be implemented. The specific consequence value assigned to each failure mode may be based on technical experience, failure analysis review, and available historical data. For instance, during contextual review  110 , the machine user  6  (or a software process executed by the machine monitoring system  16  or another computer) may indicate that a down-time of a certain machine  4  exceeding eight hours will shut-down a process line of the machine user  6 , causing serious financial repercussions. Based on this information, a consequence value of 8 may be assigned to all failure modes that may take more than eight hours to repair. This example is not intended to be limiting and the consequence value may be assigned based on other relationships to a machine operation. 
   Based on the probability of occurrence of a failure mode, the impact of the failure mode to the machine user  6 , and/or other factors, the management team  22  may assign a criticality factor to each of the failure modes (step  140 ). The criticality factor of a failure mode may indicate its risk as compared to other failure modes. The risk of a failure mode may be a function of severity of the end effect (the effect of the functional failure that results from a particular failure mode to the machine user  6 ) and the likelihood of the failure mode resulting in the end effect. The criticality factor may be assessed quantitatively (as a number) or qualitatively (low to high). In some cases, the criticality factor may be assessed as a function of the probability value and the consequence value (for e.g., a product of the probability value and the consequence value) and a criticality factor above a determined value (for e.g., “9”) may be considered high risk while a criticality factor below another determined value (for e.g., “4”) may be considered low risk. In other cases, the criticality factor may be a qualitative indicator of risk based on the probability value and the consequence value. It is also contemplated that the criticality factor may be the result of a software process executed by the machine monitoring system  16 . 
   Based on at least the criticality factor, the management team  22  may define the maintenance tasks. It is contemplated that in some applications, the machine monitoring system  16  may define the maintenance tasks based on input from the management team  22 . These maintenance task may include preventive maintenance tasks (step  150 ), predictive maintenance tasks (step  160 ), and/or reactive maintenance task (step  170 ). 
   Preventive maintenance tasks  150  are those that may be performed at a specified interval, regardless of the condition of the machine. For example, preventive maintenance tasks may be scheduled maintenance tasks that is executed on a fixed date, or after a fixed number of hours of operation of the machine  4 . The purpose of these tasks may be to prevent certain functional failures before they occur. In some applications, preventive maintenance tasks may be used to prevent failure modes which have a medium or a high criticality factor. Preventive maintenance tasks may also be defined to increase the longevity of a machine. Non-limiting examples of preventive maintenance tasks may include oil change, lubrication, filter cleaning, etc. 
   A predictive maintenance task  160  may be a maintenance task where machine maintenance is performed based on an indicator which indicates the onset, progression or the likelihood (hereinafter referred to as “onset”) of failure. As in preventive maintenance, a predictive maintenance task may be performed before the occurrence of the failure mode to prevent the functional failure. However, unlike in preventive maintenance, a predictive maintenance task is performed only when an indicator indicates the onset of failure. In some applications, failure modes with a medium or a high criticality factor where the onset of failure can be monitored by some means may be defined as predictive maintenance tasks. The onset of failure may be detected by monitoring an indictor that is related to the relevant failure mode. The onset of failure may be a gradual degradation in performance, variations in performance, or other indications that may indicate that the component may have to be repaired. The indicators may be obtained by visual observations, electrical signals, or by some other means capable of indicating the condition of the machine  4 . A change in the monitored indicator beyond a preset limit may indicate the need for repair of one or more components. For example, signals from pressure sensors at the inlet and outlet of a filter may be used as monitors for the pressure drop across the filter. In this case, the measured pressure drop across the filter may be the monitored indicator. The pressure drop across the filter exceeding a preset value may indicate the need for replacement of the filter. The preset limit may be based on technical knowledge, manufacturers data, or prior experience. 
   Reactive maintenance tasks  170  may include maintenance tasks that occur as a result of machine breakdown. A machine breakdown may be a functional failure of the machine  4  that results from a failure mode. A machine breakdown, that results in a reactive maintenance task, may be unexpected failures of the machine  4 , or may be as a result of a run-to-failure decision. A run-to-failure decision may be a decision by the management team  22  to wait until a failure mode results in a breakdown of the machine  4  before repairing the failure mode. In some applications, failure modes with a low criticality factor may be defined as reactive maintenance tasks. Economic considerations may also play a part in the definition of preventive, predictive and reactive maintenance tasks. 
   After preventive, predictive and reactive maintenance tasks are defined to respond to the identified failure modes, general maintenance management system requirements may be defined (step  180 ) by the management team  22 . The maintenance management system requirements may specify details to be recorded following a maintenance event. These details may include information such as how a repair event is initiated, data that will be recorded after a maintenance event, form and nature of the reports that compile the data, frequency of the reports, performance indicators that will be calculated, who will review the reports, and how the performance indicators will be used to optimize the maintenance management process  1000 , etc. 
     FIGS. 4A ,  4 B and  4 C illustrate the steps involved in maintenance, materials and personnel planning for preventive maintenance tasks, predictive maintenance tasks, and reactive maintenance tasks respectively of a machine  4  (step  200  of  FIG. 2 ). 
   As shown in  FIG. 4A , the procedure for conducting the defined predictive maintenance tasks in step  150  may be developed and documented (step  210 ) by the management team  22 . This procedure may include detailed step by step instructions on how to execute a predictive maintenance task. The procedures may be developed using prior experience and/or technical knowledge of the management team  22  and/or other machine users  6 , and may periodically be updated to capture best known practices that are developed over time. The frequency of the preventive maintenance task may also be defined (step  220 ). The frequency may be specified based on a time interval or based on the number of operating hours of the machine  4 . The frequency of a preventive maintenance task may also be updated periodically to capture new learnings or changed operating conditions of the machine  4 . The management team  22  may define personnel requirements to perform the preventive maintenance task in step  230 . The definition of personnel requirements may involve defining the number and the required skill level of the personnel to perform a repair. The need for external specialists, or specific technicians to perform a particular maintenance task may be identified. In some cases, the management team  22  and/or the machine monitoring system  16  may assign the maintenance task to particular machine users  6 , and automatically schedule the repair event in these machine users  6  time management calendar. The tools and spare parts required to perform the preventive maintenance task may be identified by the management team and/or the machine monitoring system  16  in step  240 . The machine monitoring system  16  may automatically upload these parts and tool requirements to an inventory management system to ensure that the requisite parts are available at the required time. The management team  22  may also identify any risks involved in the performance of the maintenance task in step  250 . Technical knowledge and/or information from previous similar repairs may be used to assess the risk. Depending on the level of the risk assigned to a maintenance task, the machine monitoring system  16  or a machine user  6  may activate specific safety procedures, safety personnel, or operational modifications to address the risk. The preventive maintenance task may be included in the annual maintenance plan by the machine monitoring system  16  in step  260 . If the frequency of the maintenance task is defined based on a time interval, the specific calendar date may be entered into the annual maintenance plan. If the frequency is based on the number of operating hours of the machine, an approximate date may be entered. In some cases, the machine monitoring system  16  may frequently update this approximate date as needed. 
     FIG. 4B  illustrates the steps involved in the maintenance, materials and personnel planning for a predictive maintenance task. The management team  22  may define monitoring indicators and their trigger levels for each predictive maintenance task in step  270 . These monitoring indicators may be automatic, manual or semi-automatic. For instance, in some cases a sensor signal may be used as an automatic indicator for a maintenance task, and a preset level of the sensor signal may trigger the maintenance task. In other cases, an observation by a machine user  6  may serve as a manual indicator to trigger a preventive maintenance task. An input from an operator based on another signal or an alarm may also serve as a semi-automatic indicator for a maintenance task. Once the indictors and their trigger levels are defined for each predictive maintenance task, the management team  22  may define detailed steps to perform the predictive maintenance task in step  280 . The management team  22  may then define the personnel needed to perform the maintenance operation in step  290 . As in the case of predictive maintenance, the need for external specialists, or specific technicians to perform a maintenance task may also be identified. In some cases, based on the progression of the indicator signal, the machine monitoring system  16  may provide advance notice of the impending maintenance task the machine user  6  assigned the repair, and/or other relevant parties. The management team  22  and/or the machine monitoring system  16  may then identify the tool and part requirements for each maintenance task in step  310 . The machine monitoring system  16  may automatically upload these tool and part requirements to an inventory management system to procure parts and to make tools available at the required time. The management team  22  and/or the machine monitoring system  16  may then schedule the maintenance task in a maintenance log and assign it to one or more machine users  6  in step  320 . 
     FIG. 4C  illustrates the steps involved in the maintenance, materials and personnel planning for a reactive maintenance task. Since a reactive maintenance task are those which results from a machine breakdown (either accidental or the result of a run-to-failure decision), a machine user  6  may use the troubleshooting process of step  330  to identify the nature of the failure and the affected component. The nature of the troubleshooting process may depend on the nature of the breakdown. In some cases, extensive investigation of the machine failure may be required, while in other cases the nature of the failure may suggest the cause. Once the machine user  6  identifies the cause of the failure, the action plan to correct the failure may be identified by the machine user  6  in step  340 . In some cases, the machine monitoring system  16  may assist the machine user  6  in diagnosing the defect and determining the required action plan. The action plan may specify the procedure for the corrective action required. The machine user  6  and the machine monitoring system  16  also identify the personnel, tools, and spare parts required for the maintenance task in step  350 , and step  360  respectively. Once the personnel, parts and tools are identified, the machine monitoring system  16  schedule the maintenance task in a maintenance and personnel logs in step  370 . 
     FIG. 5  shows a flowchart of the maintenance execution and reporting activities once a maintenance task is triggered (step  400  in  FIG. 2 ). The method by which a maintenance activity is triggered may depend on the nature of the maintenance task. For instance, a preventive maintenance task may be triggered, as in step  410 , at the frequency defined in step  220  of  FIG. 4A . A predictive maintenance task may be triggered, as in step  420 , when a monitored indicator varies from a preset limit. And, a reactive maintenance task may be triggered, as in step  430 , during a machine breakdown. Once a maintenance task is triggered, the machine monitoring system  16  may generate a work order and issue it to the assigned machine user  6  (step  440 ). In one embodiment, the machine monitoring system  16  confirms a prior task assignment (step  260  of  FIG. 4A , step  320  of  FIG. 4B , and step  370  of  FIG. 4C ). Based on the maintenance task triggered, the machine monitoring system  16  may also request the issuance of the tools and spare parts required for the maintenance task (step  450 ). The assigned machine user  6  may then execute the maintenance task in step  470 . The machine user  6  may use the documented processes (step  460 ) to execute the maintenance task. In some cases, these documented processes may be those that were developed earlier in the maintenance management operation (for instance, in step  210  of  FIG. 4A  or step  280  of  FIG. 4B ). In other cases, documentation or knowledge learned from similar maintenance tasks at the current or different worksite  10  (past learnings) may be used. The machine user  6  may use the risk assessment of the maintenance task (step  480 ) to ensure that appropriate safeguards are employed during the maintenance operation. In some cases, the machine monitoring system  16  may activate safeguards or other activities based on the risk level of a maintenance task. During or after completion of the maintenance task, the machine user  6  may generate a detailed record of the maintenance operation (step  490 ). The information included in the record may include, the work order number, a description of the maintenance performed, the date of repair, the machine  4  repaired, the type of maintenance, machine down-time, material consumption, spare part description, labor hours, cost of purchased labor (if any), engine hours, etc. The machine user  6  may create the record in a log book, in a preprinted form, or in an electronic device. Creating the record using an electronic device may include the execution of one or more software programs by a processor. The software programs may be configured to query the machine user  6  to select pre-programmed responses that most closely represents an answer to a question. For instance, following the replacement of an air filter, the software program may prompt the machine user  6  to select a response of either “light”, “moderate”, or “high” to a query regarding the condition of the replaced air filter. It is also contemplated that the software programs may permit the machine user  6  to enter responses in other ways (record verbal responses, etc.). 
   In some cases, machine codes that indicate an overview of the maintenance task may also be included in the record (step  490 ). In one embodiment, the machine codes may be included only for unplanned work orders. These machine codes may be used to track maintenance activities across multiple worksites  10  and/or projects, and improve the maintenance management process  1000 . The machine codes may include, among others, problem code, failure code, cause code, and an action code. The problem code may describe the impact of the failure on the machine  4 . The failure code may indicate the way in which the problem manifested itself and the symptoms that were detected and/or monitored. The cause code may indicate the root cause of the failure and the factors that contributed to it. The action code may indicate the corrective action taken to resolve the problem. These machine codes may be descriptive or may be one selected from multiple options. For instance, the problem code may be assigned a value “critical” or “non-critical” based on the impact of the failure on the machine  4 . The fault code may be assigned values, such as “air”, “brd”, “dop”, “elf”, etc., representing a certain type of machine failure (for example, “elf” may indicate an external leakage of fuel). The cause code may be assigned values, such as “blocked”, “break”, etc., that succinctly describe the root cause of the failure. The action code may also be assigned values, such as “adjust”, check”, etc., that concisely describe the corrective action employed. 
   The machine user  6  may then transfer the record to the machine interface module  14 . The record may be transferred to the machine interface module  14  electronically or manually. Electronic transfer may involve transferring information to the machine interface module  14  wirelessly, by transferring information in a storage device, or through a wired connection. Manual transfer may involve transferring the information to a machine user  6  who then enters the information in the machine interface module  14 . The machine interface module  14  may be located proximate to, or remote to, the machine  4 . The machine interface module  14  may further transfer the record to a machine monitoring system  16 . In one embodiment, the machine user  6  transfers data to a machine interface module  14  that is locally located at the worksite  10 . This machine interface module  14  compiles the records of multiple maintenance events and transfers the compiled record to a central machine monitoring system  16  that receives records from multiple machine interface modules  14  located at multiple worksites  10 . Information from the machine interface module  14  may be transferred to the machine monitoring system  16  wirelessly, through the world wide web, or using a wired connection. In one embodiment, the machine user  6  transfers the record directly to the machine monitoring system  16  eliminating transfer of the record to a machine interface module  14 . 
   Based on a record, or multiple records, the machine monitoring system  16  may generate a report (step  510 ). In some cases, multiple reports may be generated by the machine monitoring system  16 . The reports may summarize one or more maintenance tasks by project, machine  4 , or type of maintenance task (preventive, predictive or reactive) and may summarize records from multiple repair activities. The reports may be generated at periodic intervals (for e.g., monthly, semi-annual, annual, etc.), and may include performance indicators, such as Key Performance Indicators (KPI). 
   KPI may include performance indicators that reflect the performance or health of different areas of the maintenance management process  1000 . These areas may include, among others, work management, inventory management, and failure management. The KPI&#39;s may be updated periodically to track the health of the maintenance management process  1000  over time. 
   The KPI&#39;s for the area of work management may include performance indicators that may be used to determine whether the planned maintenance intervals are adequate, and whether all failure modes have been prevented. They may also be used to determine if the uncompleted maintenance requests (backlog) can be serviced with the available resources, and to compare performance across other similar contracts. These KPI&#39;s may include “planned maintenance hours year to date,” “planned maintenance orders past due,” “planned maintenance work orders year to date,” and “work order backlog.” The “planned maintenance hours year to date” may be a percentage representation of labor hours dedicated to preventive maintenance work orders compared to labor hours for all work orders. “Planned maintenance work orders past due” may indicate the total number of preventive maintenance work orders not yet released which have a planned issue date prior to a reference day. “Planned maintenance work orders year to date” may be a percentage representation of the total number of planned maintenance work orders completed divided by the total number of work orders completed. And, the “work order backlog” may indicate the total number of open work orders that have not yet been completed. 
   The KPI&#39;s for the area of inventory management may be used to determine if the inventory levels that are currently maintained for a contract are appropriate. These KPI&#39;s may include performance indicators such as, “inventory growth year to date,” “inventory value,” and “part consumption.” “Inventory growth year to date” may be a percentage representation of the change in total inventory value for a contract. This may be measured as the difference in dollar value of the parts received and the parts issued compared to the total inventory value. The “inventory value” may indicate the total value of all parts owned/stored for a particular contract. “Parts consumption” may be a running total of all work orders issued. 
   The KPI&#39;s for the area of failure management may include performance indicators related to unplanned work orders for a period. These KPI&#39;s may summarize the machine codes that are tracked in a record of a maintenance event, and may indicate the labor hours and money consumed in unplanned maintenance task. They may be used to compare between similar contracts, and to optimize a maintenance management system by minimizing unplanned maintenance events when it is economically feasible to do so. 
   The management team  22  may use the reports and the KPI&#39;s to gage the health of the maintenance management process  1000 . Based on these reports and KPI&#39;s the management team  22  may also modify any aspect of the maintenance management process  1000 . Some of these modifications may be targeted to improve the performance of the maintenance management process  1000 .  FIG. 6  shows a flowchart of a sample analysis and improvement process  600 . The periodic reports that are generated for a project may be reviewed (step  620 ) by the management team  22  to identify failures that have a significant impact to the project (step  630 ). These failures may be identified based on the KPI&#39;s generated or from the reports themselves. The management team  22  may also compare the KPI&#39;s from one worksite  10  to those from another worksite  10  to study similarities and dissimilarities (step  640 ). The management team  22  may create a summary report with suggested modifications to the maintenance plan. The suggested modifications may include plans to decrease the number of unplanned maintenance events (when it is economically feasible) by incorporating more preventive and predictive maintenance tasks. For instance, the failure codes of some reactive maintenance failures may indicate observable symptoms that may be tracked to predict the occurrence of the failure. A predictive maintenance task may now be designed using the observable symptom as the monitoring indicator to prevent the unforeseen occurrence of the failure. This summary report may be submitted to a project management team for approval (step  650 ). The project management team may be made up of machine users  6  who are authorized to modify the maintenance management process  1000 . It is also contemplated that the management team  22  may include machine users  6  who are authorized to modify the maintenance management process  1000 . The management team  22  may then incorporate the modifications using the machine monitoring system  16  (step  660 ). 
   INDUSTRIAL APPLICABILITY 
   The disclosed embodiments related to the maintenance management process  1000  may be used for maintenance management of any type and number of machines. In the disclosed maintenance management technique, a management team  22  and/or a machine monitoring system  16  identifies some or all of the possible functional failures of the machine  4  that impact its operation, and designs maintenance tasks of machine components that cause these failures. Different classes of maintenance tasks (such as, preventive, predictive and reactive maintenance tasks) are defined based on the criticality of the functional failure to the machine user  6 . While both preventive and predictive maintenance tasks may be implemented to repair a component before a failure occurs, these tasks may vary in how they are triggered. Preventive maintenance tasks are those which are executed at a fixed frequency while predictive maintenance tasks are those which are triggered based on a signal that is an indication of the onset of failure. Reactive maintenance tasks repair or replace a component after a failure occurs. Reactive maintenance tasks may be unexpected failures that are not preempted by a preventive or predictive maintenance task. Reactive maintenance tasks may include repair that are more economical to fix after they occur. 
   The management team  22  and/or the machine monitoring system  16  may also define procedures to carry out some or all of the defined maintenance tasks. In some embodiments, the procedures may be published and provided to relevant machine users  6 . In other embodiments, the procedures may be stored in the machine monitoring system  16  and may be accessed by the machine user  6 . 
   The maintenance management process  1000  may be implemented using a software running on the machine monitoring system  16 , one or more machine users  6 , computer hardware configured to perform the maintenance management process  1000 . Machine users  6  may also leverage a computer system (such as, the machine monitoring system  16 ) to implement the maintenance management process  1000 . Maintenance procedures, maintenance data, supplier data, machine codes, and other information related to the maintenance process may be stored in a database of the machine monitoring system  16 , and may be accessible by machine user  6 . Access to this information may be made locally through a local area network, or globally (for e.g., using the internet). 
   The disclosed maintenance management process  1000  may also employ an iterative approach to refine and optimize the maintenance management process  1000  by incorporating new learnings as and when they occur. Key Performance Indicators that track the performance of the maintenance management process  1000  may be used for the periodic optimization of the technique. 
   Since most maintenance tasks are executed before a failure actually occurs, repair events may be planned in advance to minimize the machine downtime during maintenance. Advance notice of maintenance events also minimize the impact of the machine down-time to the machine user  6 . Also, since repair events are planned in advance, the repair events may be planned to coincide with other planned machine downtime (for instance, other plant maintenance times, holidays, seasonal slow-down, etc.) to further reduce the impact to the machine user  6 . Additionally, for repair events that require a machine user  6  to travel to a worksite, advance planning of repair events allows the machine user  6  to perform multiple machine repairs in one trip, thereby saving time and money. 
   Iterative modification of the maintenance management process  1000  allows periodic modification of the maintenance technique to continuously improve by responding to changes in the worksite  10 . This continuous improvement feature will ensure the optimal operation of the maintenance management system at all times. 
   It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed method of maintenance management. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the disclosed maintenance management method. It is intended that the specification and description be considered as exemplary only, with a true scope being indicated by the following claims and their equivalents.