WO1988005918A1

WO1988005918A1 - Maintenance system

Info

Publication number: WO1988005918A1
Application number: PCT/US1988/000336
Authority: WO
Inventors: Stephen W. Leibholz; Edward J. Kapnic
Original assignee: Analytics Incorporated
Priority date: 1987-02-06
Filing date: 1988-02-05
Publication date: 1988-08-11

Abstract

A method and apparatus for aiding a technician (10) in diagnosing and repairing a faulted device (26). The apparatus includes a data base (24), a diagnostic system (22), input apparatus (20) which acquire operating condition data from the device (26), and input/output devices (18) (16) for communicating with the technician (10). The data base (24) contains diagnostic data including the possible causes of the faulted status of the device (26) and the corresponding operating conditions. The diagnostic system diagnoses the fault by determining the causes which are consistent with the acquired data, and information stored in the data base (24) for repairing the system is output to the technician (10), speech generation and recognition apparatus (28), and a radio link provide wireless voice input and output from the apparatus.

Description

MAINTENANCE SYSTEM

Field of the Invention

The present invention relates to system maintenance. In particular, the invention relates to diagnosis and repair of a faulted system, and more particularly to a method and apparatus for aiding a technician in such diagnosis and repair. Even more particularly, the invention relates to a method and apparatus for diagnosing faults in a system on the basis of data inputs and providing information for repairing the system to a technician, whereby a relatively unskilled technician may perform system maintenance which would otherwise require a highly skilled technician.

Background of the Invention

The generic job of performing maintenance on a faulted system which worked at one time may be broken down into three distinctly different tasks: diagno¬ sis to identify the component requiring removal and replacement or repair, the physical removal and replacement of the component, and repair of the component. The physical removal, repair and replacement of a component can be performed by relatively unskilled and untrained personnel. However, a highly trained and skilled technician is required to perform the diagnosis. To place such a skilled technician who can perform faulted system diagnosis in a remote field-site location has become economically impractical because of the number of failures that occur and the high cost of technician training.

Too often in the past the solution to this problem has been to adopt a re- move-and-replace maintenance strategy in place of the remove-and-repair stra¬ tegy. Thus, low-skill technicians in the field remove suspected faulty components or assemblies and replace them with known operative devices until the faulted system again works. The removed devices are then sent to a central location where they are diagnosed and, if necessary, repaired by skilled technicians. This strategy has created a number of problems. It places a burden on the supply line for extra parts and whole assemblies. It makes maintenance at the field site dependent on the receipt of major sub-assemblies. Further, many components are removed and returned to the central location which turn out not to have needed repair, but to have been simply removed on the possibility that they may be defective, in haste to restore the faulted system to service. Finally, it removes from field personnel the feeling of accomplishment associated with diagnosing the nature of a fault in a system. Another solution to the above problem has been to attempt field diagno¬ sis and repair of faulted systems using low-skill technicians who are provided with job performance aids (JPA's). Such JPA's typically take the form of a manual for a specific piece of equipment which contains step-by-step instructions for fault detec¬ tion, diagnosis, and isolation, and repair and final checkout of the equipment. The tasks necessary to accomplish the effort are described in detail, as are the actions necessary to perform them. However, diagnosis and repair using such JPA's has its own difficulties, largely because they are static in content and non-interactive in use. First, they must be designed for use by a technician having a particular degree of skill and familiarity with diagnosis of the faulted system. A JPA will not provide technicians having less familiarity and skill with sufficient information to routinely and reliably diagnose faults in the system, and will provide to the more skilled technician an overabundance of information which must be reviewed to pick out the relevant information. Also, JPA's must contain information to diagnose all possible failures of the system, regardless of their likelihood of occurrence, only a small portion of which will be relevant to diagnosing a particular faulted system. The user must identify, locate, and extract the relevant information from the large volume of non-relevant information presented. Moreover, the mechanics of accessing the information in a JPA makes it ill-suited for field use by an unskilled technician. The technician must constantly direct his attention from the JPA to the faulted system and back again, at each step of the diagnostic procedure. Such periodic diversion makes the procedure time-consuming and error-prone, especially when the technician must physically move from the faulted system to consult the JPA. It is particularly time-consuming if the technician must wash his hands before touching the JPA. Finally, such JP 's provide no training to the technician in that they do not provide a rationale for the diagnosis and repair procedures indicated.

Summary of the Invention

It is therefore a general object of the invention to provide a mainten¬ ance system which eliminates the aforementioned drawbacks of the remove-and- replace strategy and the remove-and-repair strategy.

It is a more specific object to provide a maintenance system which facilitates the repair of a faulted system in a remote field site by an unskilled technician.

It is a further object to provide a maintenance system which permits such field maintenance with effectiveness and efficiency equal to or greater than that provided by a skilled technician. It is another object of the invention to provide a maintenance system which is convenient and easy to use.

It is a more specific object to provide such a maintenance system which may be consulted and operated by the technician without diverting his attention from the faulted system, and without use of his hands.

It is another object to provide a maintenance system which may be consulted and operated from various locations about the faulted system and regard¬ less of movement by the technician between such locations.

It is a further object of the invention to provide a maintenance system which does not require extensive technician training in its use.

It is a further object to provide such a maintenance system which itself may provide technician training.

It is another object to provide a maintenance system which may at various times be used to diagnose different types of faulted systems by different technicians.

It is yet another object to provides maintenance system which may be efficiently and effectively used by technicians of different skill and training levels.

In accordance with the foregoing objects, the maintenance system of the present invention includes means for inputting operating condition data pertaining to a faulted system being maintained, data base means for storing diagnostic data pertaining to the system being maintained, and means for diagnosing faults in the system being maintained on the basis of data from the input means and the data base means. The maintenance system may further comprise voice input and output means whereby voice information and instructions may be exchanged between the diagnos¬ tic apparatus and the technician. In the preferred embodiment, the voice input and output means comprises a short-range automatic transmit-receive radio link, where¬ by the technician may engage in hands-free dialogue with the system by means of a microphone and earphone.

These and other objects and aspects of the present invention will be more fully understood with reference to the following description, appended claims, and drawings.

Brief Description of the Drawings

FIG. 1 is a block diagram of the system of the present invention; FIG. 2 is a flow chart illustrating the operation of the system; and FIG. 3 illustrates the preferred arrangement of certain components of the system. Detailed Description of the Preferred Embodiment

Figure 1 is a block diagram of the maintenance apparatus of the present invention. The apparatus is used by a technician 10 in the process of diagnosis and repair of a device under repair 26. Device 26 is a faulted system, or a suspected faulted system, which is known to have worked at one time. There are thus a finite number of possible causes of faulty operation of device 26. The apparatus comprises a central processor 12 for traffic control of the system. Processor 12 is coupled to analog/digital input means 20 which in turn is coupled to device 26 so as to provide input data to processor 12 regarding the operating conditions of device 26. Analog/- digital input means 20 comprises sensors or the like adapted to be coupled to device 26 to measure various physical properties of device 26 which are relevant to diagno¬ sis of a fault. Input means 20 may further comprise means for converting such measurements into a form compatible with central processor 12.

Also coupled to processor 12 is data base means 24 which contains data for diagnosis and repair of device 26. Such data includes specifications for the operating conditions of a properly functioning device 26. It also includes data neces¬ sary to generate information for transmission to the technician, in a manner to be described later, in the form of schematic diagrams, illustrations, verbal descriptions and instructions for data-gathering and repair procedures. It thus includes the infor¬ mation which is typically contained in a JPA. Data base means 24 also contains data representing possible causes of possible faults of the device 26, and data representing the operating conditions of the device corresponding to the occurrence of such causes, which data is used in the diagnostic process. It may further contain data representing the probability of occurrence of the possible causes.

Also coupled to processor 12 is a diagnostic system 22, which provides the system of the present invention with the expertise of a highly skilled and trained technician. Diagnostic system 22 performs diagnosis of the faulted system by receiving operating condition data pertaining to the faulted system and diagnostic data from data base means 24, and determining which causes are consistent with the operating condition data. Diagnostic system 22 then determines which operating condition data is relevant to discriminating among the remaining possible causes of the fault. Such data is then input, and further such diagnosis is performed, until one cause remains possible, or until two or more causes may not be so distinguished on the basis of available operating condition data. Data representing such cause(s) is provided as the diagnosis of the faulted system.

In accordance with an important objeet of the invention, the order in which the operating condition is input is determined by diagnostic system 22 so as to perform a diagnosis in an efficient manner, i.e. to minimize the diagnostic effort which will be required. Accordingly, if data base 24 contains data regarding the probability of occurrence of the various possible causes of a fault in a system, diag¬ nostic system 22 may select for acquisition that data which will verify or preclude the existence of the then most probable cause. Efficiency is thus obtained by investigating the most likely diagnosis first. Such a probabilistic system may be made to "learn" from its diagnostic experiences by altering the probability data in accordance with its diagnoses, whereby its diagnostic behavior is automatically varied so as to increase its efficiency. Alternatively, if the chosen measure of diagnostic effort is the number of data inputs required to arrive at a diagnosis, then diagnostic system 22 may be made to select for acquisition, on the basis of the diagnostic data stored in data base 24 and previously acquired data, that operating condition data which will minimize the number of data inputs required to arrive at a diagnosis. In this way, diagnostic system 22 selects for acquisition the most im¬ portant data, i.e. that data which, when acquired, will rule out the most then- possible causes. It will be understood that other measures of diagnostic effort, such as time required to arrive at a diagnosis, may be minimized.

Diagnostic system 22 may consist of a program which is executed by control processor 12, or may further comprise a dedicated processor.

Also coupled to central processor 12 are various means for receiving input from or providing output to a technician 10. In accordance with an important aspect of the invention, such input/output means includes means enabling the techni¬ cian to engage in a common language dialogue with the system from various loca¬ tions about the device 26. There is thus provided audio output means 16 for generat¬ ing speech signals on the basis of data stored in data base 24. Such output speech signals may represent requests for the technician to obtain data, instructions for data-gathering and repair procedures, and the like. Such output speech signals are transmitted by transceiver 28b to transceiver 28a, worn by the technician, and coupled to an audio output transducer such as an earphone 32. Microphone 30 receives speech input from the technician, such as data input, instructions, or requests for information, and provides speech signals representing the input speech. The input speech signals are transmitted by transceiver 28a to transceiver 28b and applied to audio input means 18, which converts the speech signal to data compatible with processor 12. In the preferred embodiment, transceivers 28a and 28b are radio transceivers, although other transceivers communicating over a wireless communica¬ tion channel such as ultrasonic or infrared transceivers might also be used. In a particularly preferred embodiment, transceiver 28a is a voice-controlled transceiver, and transceiver 28a and 28b form a short-range radio link of the VOX (automatic transmit/ receive) type. It will be understood that in certain applications wireless communication between technician and the diagnostic apparatus is not necessary, in which case the transceivers 28 may be eliminated and microphone 30 and earphone 32 connected via wires to audio input means 18 and audio output means 16.

The two-way voice communication system described above permits the technician to input data into and receive data from the maintenance apparatus solely by means of voice communications. The technician thus may transmit or receive information without use of his hands and without diverting his attention from the device under repair 26. Further, when wireless transceivers 28a and 28b are provided, the technician is completely free of connection to the maintenance appara¬ tus and m'ay engage in such two-way communication from any location about the device under repair and regardless of his movement about the device.

Also provided for data output to the technician is visual output means 14, such as a CRT display. Visual output means 14 is used to provide graphic or pictorial information to the technician, such as schematic diagrams or illustrations. It may also be used to provide information which would be inconvenient to present to the technician as speech, such as parts lists. It may also duplicate in visual form the information transmitted via the audio output means 16, such as for backup in case the audio output means fails, or to permit verification by the technician of the audio information received. Such visual output is provided at the appropriate times in the diagnostic or repair procedure controlled by diagnostic system 22, on the basis of data representing such visual output which is stored in data base 24.

Also desirably provided is an alternate technician input means such as keyboard 34. Keyboard may provide a backup means for inputting data in ease of failure of the audio input.

Data base 24 also desirably contains data regarding a particular techni¬ cian or technicians who will operate the system. Audio input means 18 is often required to be or is desirably configured to respond to a particular speaker's voice characteristics. Data base 24 may contain such voice characteristic information. Further, data base 24 may contain information regarding a technician's level of skill and training. Such technician proficiency data may be utilized in the interactive diagnostic and repair procedure to tailor the information requested from and supplied to the technician in accordance with his skill level. Thus, instructions to do a parti¬ cular task may be exactly as detailed as is required for the particular technician using the system to perform the required tasks. Alternatively, the system may initially provide cursory information suitable for a highly skilled technician, and provide more detailed information at the voice request of the technician.

In a preferred embodiment, shown in Fig. 3, the central processor means 12, diagnostic system 22, visual output means 14, audio input means 18, audio output means 16, and transceiver 28b are contained in a housing 110. The portion of data base 24 containing technician data is removable from the apparatus, and may include non-volatile but alterable storage means housed in a plug-in cartridge 112 having connector means for coupling to control processor 12. The portion of data base 24 containing diagnostic data and data representing outputs which are specific to a particular type of device under repair 26 is preferably similarly removable and housed in a plug-in cartridge 114. Maintenance apparatus so constructed may be easily configured for operation by a particular technician or for diagnosis and repair of a particular type of device. Similarly, analog/digital input means 20 is preferably removably coupled to control processor 12 by connector means, so that such input means may be easily changed according to the type of device under repair.

Figure 2 is a flow chart illustrating the operation of the system of the present invention. Operation is begun at step 70 by a verbal command from the technician. At this time, analog/digital input means 20 will have been coupled to device 26, and all device and technician data will be available in data base 24. In step 72, data regarding the operating characteristics of device 26 is input. General¬ ly, this will be directly from device 26 via analog/digital input means 20, although it may also be input by transmitting a verbal query to the technician who obtains the data and verbally inputs it via audio input means 18. In step 74, the data acquired in step 72 is compared with the device specifications stored in data base 24. If the input data is within specifications, step 96 is executed and an output signal is gener¬ ated indicating that device 26 is operating normally. If the data is not within specifications, step 76 is executed and diagnostic system 22 attempts to diagnose the fault on the basis of the acquired data. In step 78, a determination is made as to whether the results of the attempted diagnosis of step 76 are sufficient to identify the cause(s) of the fault in device 26. If not, in step 80 a determination is made of which data should be obtained next in order to continue diagnosis.

In step 82, a determination is made as to whether input of the next data will require action by the technician, or whether such data can be input directly via analog/digital input means 20. If the technician action is required, in step 84 an output is transmitted to the technician identifying the action required. Such action may be to establish certain operating conditions in the device under repair 26, with data acquisition performed by input means 20 under those conditions, or may involve data acquisition and input entirely by the technician. With certain faulted systems, such as certain electronic systems, it is feasible to obtain input data entirely by analog/digital input means 20, and the technician need not be involved in the data acquisition and diagnostic process. For many faulted systems, however, and particu¬ larly for automotive systems, it is more efficient to incorporate the technician in the process. For instance, it is cheaper and easier to have a technician visually inspect a system and report his observations than to provide an automatic data acquisition system to do so. In such circumstances, the input data selection and order can substantially affect the speed of diagnosis.

If technician action is required, instructions and other information for performing such tasks are output in step 86 to the technician via the audio output or the video output. The maintenance system then in step 88 waits for technician input indicating that the requested action has been taken, and in step 90 the required next data is input to the maintenance system. The diagnosis, next data selection, and data input steps are then repeated until a determination is made in step 78 that sufficient data has been input to identify the cause(s) of the fault in device 26. Then in step 92, the system outputs repair instructions and information to the technician via the audio output means or the visual output means. As has been indicated, the degree of detail of such instructions may be tailored to the proficiency level of the technician either in accordance with stored technician proficiency data or in response to technician requests for more detailed information. The system then waits until it receives from the technician an indication that the requested repair has been completed in step 94.

The system is then returned to step 72 for a determination of whether the attempted repair action has been successful: Data regarding the operation of device 26 as repaired is input in step 72, which data is in step 74 compared with the specifications for the device. If the attempted repair has been successful, the data will be within specifications and operation of the system will branch to step 96 where an output indication of normal operation is made. In accordance with an important aspect of the present invention, the device data obtained from the faulted system in step 72 and the data regarding the successful repair are in step 98 added to data base 24 so as to update it. In this way, the system is able to learn from its experience and alter its data input and diagnosis strategies to more efficiently and effectively diagnose faulted systems. Data base 24 is also updated if the device 26 was not faulted, i.e. if on the first comparison in step 74 the device data was within specifications. In this way, data is stored which enables generation of reports for each unit which has been tested, and summary reports for all units which have been tested, for use by those responsible for device maintenance. Such information may also be used to control inventory, parts ordering and the like on the basis of the repair history. Such information is also useful in planning modification to the system to increase reliability. An important feature of the present invention is that such information is automatically generated and stored by the maintenance diagnostic system without any additional record-keeping requirements imposed on technicians or other personnel. If the attempted repair was not successful, the diagnosis and data input steps will be performed until another diagnosis is completed and another repair is indicated. In such subsequent diagnosis, the prior operating condition and repair data may be taken into account.

In step 100, a determination is made as to whether the device has been repaired. If not, the diagnostic procedure is ended in step 106. If a repair has been made, in accordance with an important aspect of the present invention, the techni¬ cian may in step 102 request training on the basis of the repair. If training is requested, information stored in data base 24 as to the rationale for the input data selected and for the diagnosis based on the data obtained is output to the technician in step 106. Such output may also be tailored to the particular skill and training level of the technician. In this way, the technician may improve his skill and training level.

The method and apparatus which has been described herein form a main¬ tenance system which enables a relatively unskilled technician to perform field diagnosis and repair of faulted systems. In the maintenance system, the data base and diagnostic system substitute for the knowledge and the diagnostic skills of a highly-skilled technician. Such knowledge and the diagnostic skills may be accessed by the technician from any location about the faulted system being maintained, and during movement between such locations, due to the radio communication channel between the technician and the maintenance system. Moreover, by providing voice input and output for exchange of information between the technician and the maintenance system, the technician may supply information to and receive informa¬ tion from the diagnostic system without diverting his attention from the faulted system being maintained, and need not use his hands to do so. Because the system is controlled by spoken commands, the technician will need little training in its use. Because the system provides for direct input of data from the device under repair, relevant data may be obtained without the time-consuming process of data acquisi¬ tion and input by the technician. Thus, the speed and accuracy of the diagnostic process is increased. The speed and accuracy is also increased for those maintenance tasks which are performed by the technician because the system varies its informa¬ tion outputs to adapt to the skill and training level of the technician operating it. Further, the only information which is transmitted to the technician is that required to perform a particular task, at the time at which the diagnostic system determines that such task should be performed. Thus, the technician need not review large volumes of information in order to locate relevant information. Speed and accuracy of diagnosis is also improved because the system stores the results of each diagnosis and attempted repair, and modifies its diagnostic behavior in response to this accu- mulated information. Further, the system can provide technician training by provid¬ ing the technician with a description and explanation for the diagnostic procedures it has undertaken.

While the invention has been described with reference to a preferred embodiment, it should be understood that modifications may be made by those skilled in the art without departing from the spirit and scope of the invention including that defined by the appended claims.

Claims

What is claimed is:

1. Maintenance apparatus for assisting a technician in diagnosing and repairing a faulted system, comprising: control means for controlling the operating of said apparatus; input means coupled to said control means and to said system for inputting operating condition data from said system; data base means coupled to said control means for storing data, said data base means containing diagnostic data representing possible causes of possible faults of said system and operating conditions of said system corresponding to said causes; and diagnostic means coupled to said control means for receiving and comparing said diagnostic data and operating condition data and for selecting from said possible causes those causes which are consistent with said operating condition data.

2. Apparatus as in claim 1, wherein said diagnostic data includes data representing the probability of occurrence of said possible causes, and said diagnostic means selects operating condition data for input in response to said probability data.

3. Apparatus as in claim 2, wherein said control means comprises means for modifying said probability data' on the basis of faults diagnosed by said apparatus.

4. Apparatus as in claim 1, further comprising means coupled to said control means for receiving input from and providing output to said technician.

5. Apparatus as in claim 4, wherein said diagnostic data includes data representing technician procedures for performing data acquisition and repair tasks, said diagnostic means selects particular such tasks to be performed, and procedural data for performing the selected tasks is output when such tasks are selected.

6. Apparatus as in claim 5, wherein said output means comprises visual display means, and said procedural data includes data representing pictorial or graphic information.

7. Apparatus as in claim 5, wherein said procedural data includes data representing verbal information, and said output means comprises means for outputting said verbal information as audible speech.

8. Apparatus as in claim 5, wherein said data base means includes data representing technician proficiency, and said control means varies the output of said procedural data in response to said proficiency data.

9. Apparatus as in claim 4, wherein said technician input means includes means responsive to technician speech for generating input data representing said speech.

10. Apparatus as in claim 1, wherein said data base means includes a removable portion containing said diagnostic data.

11. Maintenance apparatus for assisting a technician in diagnosing and repairing a faulted system comprising: control means for controlling the operating of said apparatus; input and output means coupled to said control means for inputting data including system operating condition data into said apparatus and for outputting data from said apparatus; data base means coupled to said control means for storing data, said data base means containing diagnostic data representing possible causes of possible faults of said system and representing system operating conditions corresponding to said causes; and diagnostic means coupled to said control means for receiving and comparing said diagnostic data and said operating condition data and for selecting from said possible causes those causes which are consistent with said operating condition data; wherein said input and output means includes means for two-way voice communication between said technician and said apparatus.

12. Apparatus as in claim 11, wherein said communication means includes radio transmitter and receiver means for transmitting voice input and output between said technician and said apparatus.

13. Apparatus as in- claim 11, wherein said radio transmitter and receiver means comprises a transceiver of the VOX type.

14. Apparatus as in claim 11, wherein said diagnostic data includes data representing technician procedures for performing data acquisition or repair tasks, said diagnostic means selects particular such tasks to be performed, and procedural data for performing the selected tasks is output when such tasks are selected.

15. Apparatus as in claim 14, wherein said data base means includes data representing technician proficiency, and said control means varies the output of said procedural data in response to said proficiency data.

16. Apparatus as in claim 15, wherein said data base means includes a removable portion containing said proficiency data.

17. Apparatus as in claim 14, wherein said control means varies the output of said procedural data in response to voice instructions input from said technician.

18. Apparatus as In claim 11, wherein said data base means includes a removable portion containing said diagnostic data.

19. Apparatus as in claim 11, wherein said diagnostic data includes data representing the probability of occurrence of said possible causes, and said diagnostic means selects operating condition data for input in response to said probability data.

20. Apparatus as in claim 19, wherein said control means comprises means for modifying said probability data on the basis of faults diagnosed by said apparatus.