GB2349718A - Producing systems engineering models - Google Patents

Abstract

Systems are developed over a plurality of development sites, 401,402,403, using an information model 409. The information model is derived from templates and information is added to a template locally in accordance with rules defined by the template. The local contribution includes defining links to local information structures at other sites. In this way, it is possible to populate the local information structure and thereafter test the integrity of the global information structure, by accessing distributed information via said links, whereafter the local information structure is updated in response to the global integrity test.

Description

Producing Systems Engineering Models Field of the Invention The present invention relates to developing systems over a plurality of development sites. In particular, the invention relates to the development of systems using information models, wherein said models are represented by a global information structure.

Background to the Invention The development process for industrial products is complex and expensive. Systems are developed through information, such as the requirements, design, development plan and test information etc. This information is used to control the whole process of systems development and subsequent manufacture. The nature of the information is relatively complex.

There are also complex relationships between the pieces of information that may show, for example, the traceability between requirements and design, or between the requirements and the test.

Systems engineering information contained in a model is that required to define the product, to define the development of the product and to define how the product is tested, operated and manufactured. This information defines what the product must do, how it is tested and how it is developed. It may or may not include the actual design of the product.

Problems arise if a product is being developed over a plurality of sites and as the size and complexity of the product increases it is likely that the addition overhead in terms of co-ordinating the activities increases even more rapidly. Thus, it is possible for relatively modest amendments made at the lowest level of the development, possibly re-specifying the size or weight of a bolt for example, to impact on much higher level constraints, such as the overall weight of the product as a whole. Thus, there is a desire to move forward quickly in terms of finalising the design but at the same time efforts must be made to ensure that the overall integrity of the design is maintained.

Summary of the invention According to a first aspect of the present invention, there is provided a method of developing systems over a plurality of development sites using an information model, wherein said model is represented by a global information structure, that comprises a plurality of linked local information structures, comprising the steps of: contributing to a local information structure; provisionally populating said local information structure with new data; testing the integrity of said global information structure in response to said provisional local data; and updating said local and global information structures in response to said test.

An advantage of the present invention is that the testing procedures for ensuring overall product integrity are performed technically and automatically within the system itself, such that it is not possible for a designer to make modifications or add new design data that is inconsistent with the overall integrity constraints.

According to a second aspect of the present invention, there is provided a method of developing system over a plurality of development sites, comprising the steps of, at a first site, loading a template for an information structure; and contributing locally to said information structure in accordance with rules defined in said template, wherein said local contribution includes defining at least one link to a local information structure at said second site, substantially derived from said template.

Brief Description of the Drawings Figure 1 shows a facility for the design, manufacture and testing of civilaircraft; Figure 2 illustrates a process engineering life cycle ; Figure 3 shows a configuration item structure produced from the process engineering cycle illustrated in Figure 2; Figure 4 illustrates essential aspects of the preferred embodiment; Figure 5 illustrates an example of a systems template; Figure 6 shows a design work station, including a processing system, a display device and input devices; Figure 7 illustrates the computer system identified in Figure 4; Figure 8 shows operations performed at the work station illustrated in Figure 6; Figure 9 expands the step of information model development identified in Figure 8; Figure 10 details the modification of structure procedure identified in Figure 9; Figure 11 details the process for the modification of information data identified in Figure 9; Figure 12 expands the procedure for the establishment of product definitions identified in Figure 2; Figure 13 amplifies the creation of the development system process identified in Figure 2; Figure 14 expands the process for the formulation of the test system identified in Figure 2; Figure 15 illustrates a first window displayed on the monitor shown in Figure 6 ; Figure 16 shows an addition window displayed on the monitor shown in Figure 6; Figure 17 illustrates the relationship between development sites; Figure 18 identifies the position of flap motor design within a global information model ; and Figure 19 illustrates the distribution of the entire global model over a plurality of local sites.

Detailed Description of The Preferred Embodiments The invention will now be described by way of example only with reference to the previously identified drawings.

A facility for the design, manufacture and testing of civil aircraft is illustrated in Figure 1. The facility has been built over a plurality of sites and sites 101 to 106 are shown in Figure 1. The facility may be spread over a greater area or several relatively independent facilities may interact, possibly spanning national borders and even resulting in intercontinental collaboration.

In the illustrative example shown in Figure 1, there is provided a central administration and market research site 101, a mechanical research and development site 102, an electrical and electronic research and development site 103, a sub-assembly construction site 104, a main assembly site 105 and a test and despatch site 106. Mechanical transportation facilities are provided where appropriate which, in particular, provide for the transportation of sub-assemblies from site 104 to the main assembly site 105 and for the transportation of completed aeroplanes, such as aeroplane 107, from the main assembly site 105 to the test and despatch site 106. In addition, the sites are connected by means of an electronic network 108, with local area networks being provided within each individual site and possibly wide area connection being provided to other installations, either via public switched networks or by dedicated communication channes.

Thus, for example, the main administration site 101 may communicate with other installations by means of a satellite link 109.

The design and manufacture of aeroplanes requires many technologies and engineering procedures to be co-ordinated and in order for the specific engineering developments to take place, the overall interrelationship of the system needs to be developed in a process usually referred to as systems engineering.

Systems engineering procedures result in the development of a systems information model and in the present embodiment, this model is developed over a plurality of development sites with communication between the sites being provided by the network 108. The information model is represented by a global configuration item structure and this structure comprises a plurality of linked local configuration item structures.

Contributions to local configuration item structures are made at individual work stations within individual sites, such as the mechanical research and development 102.

The addition or modification of new data results in a local configuration item being provisionally populated with the new data. New data must be added in this way in order for the overall development process to move forward. However, real progress is only made if, while populating information as part of the development process, the overall integrity of the development is maintained globally. Traditionally, this is achieved by people and departments of people being responsible for the co-ordination process but in accordance with the present embodiment, much of this co-ordination has been replaced by technical processes directed at maintaining the integrity of the overall project while the design work takes place.

In particular, the system of the preferred embodiment is configured to test the integrity of the global configuration in response to local configuration items being populated with new data. If the new data can be integrated with the overall design, the local and global configuration items are then and only then updated in response to the testing step.

An overall process engineering life cycle is illustrated in Figure 2.

Firstly, at step 201 product definitions are established that relate primarily to the technical requirements of the plane itself. Thereafter, a development system is created at step 202, making reference to the requirements of passengers and operators using the aeroplane in addition to the available facilities within the construction sites and the design sites.

At step 203 a test system is formulated, formulating tests to be performed on prototype units, possibly of a destructive nature, in addition to tests to be performed on production units, clearly of a non-destructive nature.

Thereafter, a manufacturing system is developed at step 204 specifying how production units are to be manufactured. Finally, at step 205 an operational system is defined setting out requirements for maintaining the aeroplane during its operational life.

Before step 204 may be initiated, it is necessary to have a complete product definition that may be considered as the totality of the plans for the aeroplane design. In the present embodiment, these project plans are represented in the form of a configuration item structure, shown at 301 in Figure 3. This configuration item structure provides the unifying definition of product definitions 302 established at step 201, a development system 303 created at step 202 and a test system 304 formulated at step 203.

The development occurs over a plurality of sites, such as the six sites illustrated in Figure 1. Each of these sites may independently develop a local information model relevant to the responsibilities of that particular site. These six independent information models are illustrated in Figure 3 as models 301, 302,303,304,305 and 306 generated at sites 101 to 106 respectively. In combination, these local information models constitute the overall global information model, illustrated as lying within the boundary 307.

The creation of the local information models is essentially performed in response to two basic operations, illustrated as 308 and 309. The process is initiated by receiving a systems template from a central source, which may be a publicly available source or may be available from an internal network.

Thus, process 308 represents the distribution of systems templates to the sites 101 to 106 where the respective information models 301 to 306 are established. Thereafter, the system templates are populated and modified in accordance with the rules specified within the templates themselves.

Sometimes, the attributes within an available systems template may be insufficient and requests may be made from development sites for system templates to be modified. Under these circumstances, assuming modification is found acceptable, the modified system templates may be made available for particular model developments. Thus, in addition to the generally available system templates at 308, modifications are supplied to process 309 from which these modified templates may be made available to particular sites.

Thus, in the example, a modified template is made available to information models 303 and 306.

In some situations, the general overall functionality of the system may evolve if a modified template, present at process 309 is found to be particularly useful, resulting in the modified template replacing or being added to the general purpose system templates present at process 308. Thus, in this way, the functionality of the system templates may evolve and improve in response to low level activities being performed at the individual development sites and being passed up, as distinct from relying upon improvements being anticipated and imposed in a top down fashion.

A problem associated with the development of system models over distributed sites is that of ensuring that development work is co-ordinated and that tests applicable to the overall global structure are maintained. Merely populating a database or similar static structure does not take account of all of the requirements present when working through the development of a project. In particular, this approach does not take account of development order and precedence, which are required in many situations to ensure that a particular aspect of the design is not completed before other aspects of the design that are being formulated elsewhere.

An important aspect of the preferred embodiment is illustrated in Figure 4. The systems are being developed over a plurality of development sites which, in Figure 4, are illustrated as sites 401,402 and 403. An information model is represented by a global information structure, effectively contained within the overall environment 404. Thus, the global information structure comprises a plurality of linked local information structures 401 to 403. In order to develop the system and populate data within the models, an input is received at step 405 which initially only provisionally populates the local information structure with the new data. At step 406 a test is performed to test the integrity of the global information structure in response to the provisional local data being added thereto. In order to do this, information is required from elsewhere within the global structure. Thus, the testing process allows the new data to be tested with respect to related aspects of the overall global structure. Then, after performing this test, the local and global information structures are updated.

Thus, the addition of new data at site 403 may require a test to be performed with respect to data contained at the local information model of site 401. Test process 406 issues a command over a network connection 408 resulting in information being retumed via said network from the local information model 409 of site 401.

In this way, it is possible for the local sites to facilitate relevant system development for their own area of specialisation. However, where appropriate, the information models make reference to parts of the overall global structure in order to ensure that the development is occurring in accordance with the globally defined constraints.

The configuration item structure is fabricated from a programmable systems engineering template or information model, combined with similar templates or models for the definition of the process. The template or model enables programs written by different groups to inter-operate with each other, through knowledge of the common information model. This approach allows groups of people developing the design to be able to exchange information and create compatible designs or programs through exchanging parts of the mode, or by building their own model from a compatible template. In this way, a complete environment for system engineering designs or programs can be built-up by different distributed groups.

The model acts as an architecture to which each of the groups can adhere to create their own components and tools. These tools will work with one another because the architecture is compatible. The template is actually an information model for systems engineering information and therefore shows the information used in systems engineering, including the links between the information and the attributes of the objects and the links.

The template can be expressed through tools such as DOORSw or through standard notations such as XML. The XML language is used to construct such a model and the generation of UML models or DOOR models or to other systems engineering tools can be fabricated in such way as to be automatic.

The systems engineering information contained in the model is that required to define the product, to define the development of the product and to define how the product is tested, operated and manufactured. This information defines what the product must do, how it is tested and how it is developed. It may or may not include the actual design of the product.

To use the model, a user requires (usually downloads possibly via the Worldwide Web) the latest version of the model/template. The model is used directly for structuring and storing information and it may be tailored by the user. Providing that the tailoring conforms to the standard supplied with the model, the user's information will still be usable by others.

Once the user's information is in the form defined by the model, the user will be able to construct programs which access this information. The user will be able to exchange information with others and the user will be able to use other programs by users of the same model. Thus, this allows interaction between different development organisations to produce a composite system for the creation of products. This ability to interact can be controlled by either side to prevent unwanted intrusion. Systems can accept the information and change their own or they can reject that information if the user does not have access rights or has defined the information incorrectly.

Typical examples of the tools to be used in this environment are value engineering and contract management. These tools will typically be developed by different groups yet each of them will involve common information. Cost information will be needed by both the value engineering and contract management applications. To use such information successfully in both cases, it must be available in the same format. Thus, the information model defines that format.

In some cases, the tools must be used in a specific order. The information must be in a specific state for a software tool to be able to operate validly. The state of the information is stored with the information itself.

The model supplied is intrinsically programmable, allowing users to modify it to describe their specific process. For example, a user may define an incremental development process that is being used to develop a specific product or define a local unit of currency etc. This information is encoded in the self description of the model allowing the receiver to use it automatically or semi-automatically.

Two different development groups may be considered, each of which develops a single tool. These two groups are producing two separate tools for areas in which they are working. Thus, for example, one group may produce a tool for cost benefit evaluation, that is checking the cost of a design against a benefit which it is meant to bring and the second group, possibly at a different company, may produce a tool for handling changes during the course of the development.

Both groups load the systems model into their system. The model provides information structures that both will use. For example, it defines how to store requirements and how to classify each requirement on a scale according to its importance. Both groups use this attribute.

The first group writes their cost benefit tool and fills in data relating to cost and benefit, whereafter they inform the process model that this has been done. The second group produces a tool to evaluate changes, before deciding on whether to implement the change. The tool looks at the potential costs and impacts of change, that is it uses a similar set of information attributes to the first group. The tool also cannot be used until a specific point in the process, when the requirements and designs are both defined and are linked traceably. The tool can examine the process state before it starts and change it after it has finished.

Provided that both groups use the same model, the tools would be interoperable. Group one would be able to sell their tool group two and visa versa and tools could be used on the same set of data.

If either group had need to create a new attribute, they would propose this to the owner of the systems engineering model. This could then have been accepted as a new attribute and a change made to the model, as described with respect to Figure 3.

The model covers the full set of systems information and it adopts a set of information which, for example, could conform to the EIA 632 and ISO 15288 standards. The model applies to systems containing hardware, software and people or any combination of all three.

The components contained within the model are the product definition model (requirement, design etc), the development information model (schedule, deliverables, work breakdown structures etc), test information (test planes, test scripts, expected results, actual results), operational and manufacturing information, the process model (the sequence of prototypes and successive releases in the product life cycle) the links between this information (for traceability between requirements and design, between a deliverable and a person responsible for it, or between a component and its tests), the concept of allowing users to modify a model and to describe those modifications through self-descriptive messages and a self-descriptive format in XML which describes the model in use by one user for another when a message is exchanged between them.

The model is both programmable and self-descriptive, in that, given the model, an external user is able to read and write information to the system that lies behind the model. The model essentially describes a systems engineering life cycle that is being used and gives sufficient information for extemal systems to interact with it.

The model also defines key interfaces to the systems engineering information. It will interact with a UML template for example.

The systems engineering model may be published, possibly on the Worldwide Web, so that users can download the latest version. Users would then be able to write compatible programs that could exchange information with users of the model. A user can propose changes to the model, to enable (for example) a new global attribute to be defined. This would result in an update to the model.

The system facilitates the ability of different groups to write software tools which are interoperable. This allows a large suite of tools to be generated by a distributed group of users. The system provides the ability to exhibit a general systems engineering model on the Worldwide Web that can be downloaded for use by different groups. The system also provides central control of the information model which allows it to be updated in such a way as to remain compatible with old software tools written before the update.

An example of a systems template is illustrated at 501 in Figure 5 and the development of this systems template results in an information model illustrated at 502. The systems template 501 includes a product definition model 503, a development information model 504, a test information model 505, an operational and manufacturing information model 506, information links 507, self-descriptive modification messages 508 and process definitions 509. The product definition model 503 includes associated process definitions and the inclusions of these process definitions ensure that the order and precedence of development of the product definition model is enforced. Similarly, process definitions also exist for the development of the information model 504, the test information model 505 and the operational manufacturing information model 506. Furthermore, there is an overall process definition which controls the relationships between the individual model components 503 to 506. Furthermore, the process definitions include rules relating to order and precedence or individual items within the defined models, thereby ensuring that these models are constructed in an appropriate sequence. Thus, the system template enforces a methodology for the population of information model 502 with real systems engineering data.

A member of a systems engineering group is shown in Figure 6 working with a conventional computer system 601, having a processing unit, a display device 602 and input devices 603. In addition, computer system 601 communicates with similar systems via a network connection 604 communicating with the facility network 108. Executable instructions are also loadable into the computer system 601 by means of disk drives 605 configured to receive magnetic media or optically encoded media.

The group member shown in Figure 6 is actually part of the electrical and electronic research and development team housed in site 103. In particular, for the purposes of this example, the group member has been given the task of designing and/or specifying a drive motor assembly which in the finished aeroplane will be used for actuating flaps extemal to the aeroplane. In this respect, the group member shown is constrained by mechanical requirements specified in mechanical research and development 102 and he in tum will define specifications to sub-contractors based on his requirements.

All of the work done by the group member shown in Figure 6 involves taking a lead from the information presently contained within the information model structure, populating the model on the basis of the added or modified aspects of the design and then making the new constraints, defined by the modified information model structure, available to sub-contractors and coworkers responsible for implementing the subsequently specified detail.

In order to ensure that data is added to the information model in a coordinated way, the definition process is initiated by making reference to a template, whereafter appropriate design information is added to at designated fields to create an information model 502. The model evolves as the design work continues, in accordance with structures and processes encoded in the template. If not already held locally, the template is uploaded over network 108. In alternative applications, the design work may take place over a broader base, with blank templates and ongoing projects being available via intemet works and where appropriate, over the Intemet.

Computer system 401 is of a substantially conventional design as illustrated in Figure 7. Central processing unit 701 communicates with local memory devices 702, a graphics card 703 and a network card 704 via a PCR bus 705. In addition, an input/output interface 706 provides communication with a serial port 707, a keyboard interface 708, hard disk drive 709, an optical disk drive 710 and floppy disk drive 711.

Operations performed with respect to the work station illustrated in Figure 6 are identified in Figure 8. The procedure shown in Figure 8 illustrates the initiation of a systems engineering project. At step 801 a systems template is downloaded, whereafter a question is asked at step 802 as to whether any modifications are required for the template. If this question is answered in the affirmative, modifications to the template are made in accordance with standards supplied for the template, at step 803, which may represent a requirement for modifications being made for use with respect to a different life cycle, for example. Thereafter, or in response to the question asked at step 802 being answered in the negative, information is structured and stored using the template to develop an information model 502, at step 804.

At step 805 a question is asked as to whether links are required to other sites within the model and when answered in the affirmative a link is created at step 806 with dependencies being updated. Thereafter, steps 804 to 806 are repeated for the duration of the design session.

Step 804 for identifying the development of the information model, is expanded in Figure 9. Figure 9 emphasises the situation to the effect that the user may alter the structure of the information model 502 at step 901 or, alternatively, the user may modify information data at step 902; these processes being operated whenever appropriate.

Step 901 for the modification of structure is detailed in Figure 10. At step 1001 a user identifies a situation to the effect that the addition of an information item to the information structure is required, whereafter, at step 1002, the user provisionally adds a new item to the information structure.

At step 1003, the system performs order and precedence processing and at step 1004 a question is asked as to whether the item has been accepted. When answered in the affirmative, the information model is updated at step 1005, thereby completing the process.

Alternatively, if the question asked at step 1004 is answered in the negative, to the effect that the new item has not been accepted, the user is alerted to the nature of acceptable requirements at step 1006.

Process 902 for user modification of information data is detailed in Figure 11. At step 1101 the system is informed of the fact that the user requires an update of the information structure with new data. Thereafter, at step 1102, the structure is provisionally populated with the new data whereafter, at step 1103 dependency processing is performed.

At step 1104 a question is asked as to whether the new data has been accepted and if answered in the affirmative, the information model is updated at step 1105 and the process completes. Altematively, if the question asked at step 1104 is answered in the negative, to the effect that the new data has been rejected, the user is alerted as to appropriate requirements at step 1106.

The procedure for the establishment of product definitions is identified at step 201 of Figure 2 and expanded in Figure 12. At step 1201 business requirements are defined whereafter at step 1202 user requirements are specified. This is then followed by step 1203 where system requirements are specified, followed by the detailed design procedures being performed at step 1204. At step 1205 the information model is updated.

In the example of aeroplane manufacture, the specification of business requirements at step 1201 may include reference being made to the number of sales of aircraft, the required retum and investment, the nature of competition, the desired profitability, the total investment level, the desired quality of the aeroplane, airline requirements, and maintenance requirements etc. In addition, interrelationships will exist between parts of this information, such that the number of sales may be dependent, for example, on satisfying airline requirements.

User requirements defined at step 1202 relate to the end users and this procedure would include defining the different user types, consisting of passengers, crew, maintenance staff and even traffic control. All these users may be approached and asked questions to determine their requirements from which scenarios may be structured. These in turn lead to an identification of the overall requirements being placed on the aeroplane. For example, if short journeys are being made the aeroplane will incur many take-offs and landings. Similarly, if there is to be a significant amount of flying across oceans then safety issues and reliability become of greater importance.

From considering scenarios developed from end users, consideration may be given to optim size of seats and the ease of getting in and out of the aeroplane. Similarly, questions may be asked as to the facilities that are provided by the aeroplane along with questions concerning maintenance and accessibility.

Clearly, it would be unusual to satisfy all of the constraints, but effort can be made to meet as many of these as possible.

The definition of system requirements at step 1203 includes reference to the major functionality of the aeroplane, which will clearly involve a requirement to transport passengers, a requirement to power the plane and a requirement to navigate the plane. However, there could be other requirements placed upon the design such as a requirement to prepare meals or a requirement to provide entertainment systems etc. Thus, these system requirements are specified without, at this stage, making specific reference to actual aeroplane design.

The definition of performance requirements leads to subsidiary requirements. For example, if a particular thrust is specified this would in turn lead to a specification of the amount of fuel required and the rate at which this fuel must be supplied to the engines etc.

Step 1204 comprises the architectural design of the aircraft for which major components are specified including their interrelationships (from an interfacing point of view) and their spatial relationships within the overall design. Thus, a hierarchical structure of the major components is designed, including their interrelationships and their controls, to the extent that a particular component may only operate after the status of another item has been determined.

As the hierarchical structure is developed, precedence and order are imposed. The ordering of the design takes account of situations where component B cannot be fully designed until component A has been designed. Similarly, precedence requirements would state that in terms of an interrelationship, B must satisfy a requirement set by A and A has precedence over B such that A may change this requirement. However, B is not allowed to make a change to the requirement without first receiving permission from A. Anyone involved in the design of component B must be aware of this precedence constraint in order to maintain the overall global integrity of the design. In the embodiment, a precedence and order are enforced by relationships established between models and information items, with specific tests invoking these relationships in order to obtain information for the appropriate test to be completed. The relationships may exist across a plurality of development sites.

As shown in Figure 12, the processes 1201 to 1204 are performed in the order as shown. This ensures that efforts are not directed towards the design and development of systems that do not really have any sound business foundation. Thus, initially, business requirements are specified at 1201. Similarly, by making reference to user requirements next, an imposition is placed on the overall design process to ensure that a product is not designed for which there are no customers or which would at least result in reduced customer satisfaction. Thereafter it is possible to define system requirements from which it is possible to move on to the actual design process. However, the links between items maintain their presence such that at any point in time, a design may be considered to check that it does satisfy design requirements and if necessary, further reference may be made further up the tree structure to consider user requirements and business requirements, possibly including communication between sites over links.

In the template shown in Figure 5, the product definition model 503 is populated in response to invoking the procedure shown in Figure 12. There is a process associated with model 503 that activates a state machine, executable on CPU 701, thereby forcing user input to be conformed to the sequence specified in Figure 12.

The enforcement of order, as required for process 201, during the establishment of product definitions, is not enforced in the same way for the creation of the development system identified in process 202 and amplifie in Figured 13. Procedure 202 involves the process of populating models 1301, 1302,1303 and 1304 in accordance with the definitions of the development information model 504 derived from the template. As shown in Figure 13, there is no particular order in which these areas of the model are populated but account must be taken of precedence within the elements of the structures themselves. Work breakdown structure 1301 defines an identification of all the work that absorbs resources and is organised with respect to the similarity of the work concerned. In this respect, the similarity of the work is defined in terms of the people and the facilities required in order to complete the work. Organisational breakdown structure 1302 defines chains of command within the organisation itself and effectively defines responsibilities within the organisation and reporting requirements.

The cost breakdown structure 1303 identifies the pricing of all the work components and standards 1304 define standards that should be adhered to during the overall process. Thus, the collection of information items within the structures results in the development system being created for implementation within the development information model 504.

Process 203 for the formulation of the test system, resulting in population of the test information model 505 is expanded in Figure 14. A coordinating test system process 1401 is derived from a definition of test system requirements 1402, test system design 1403 and test policy 1404.

Processes shown in Figures 12, 13 and 14 have been described as relatively high level to give an indication of the type of data that is required in order to perform the population of the template. At the actual implementation level, as performed by the group member shown in Figure 6, individual items are populated within the structure which are themselves further expanded within a hierarchical model. Each of these items has associated processes that are executed on central processing unit 701 in the form of state machines, in order to maintain the integrity and validity of the overall global model as the information is received. Thus, in this way, it is possible for group members to work on detail at any level within the hierarchy while at the same time maintaining the integrity of the global design.

A typical display screen made available to a group operator, via visual display unit 602, is indicated in Figure 15.

The first window 1501 is displayed to the group member as shown in Figure 15, setting out requirements that a group member's design must satisfy. Thus, these requirements represent precedence imposed upon the developer from other definitions within the structure. The developer also has access to a second window 1502, as shown in Figure 16 after this window has been selected. This window allows the developer to define design specifications at the developer's level of activity. Thus, in this example, developments are being made with respect to a processor board, server motors and connectors along with other components. These specifications are developed by the group member and then subsequently imposed upon other group members or external contractors. Thus, window 1501 details the precedence imposed upon the developer with window 1502 defining the precedents that would be imposed lower down within the structure.

In the example described with respect to Figures 15 and 16 it has been assumed that the group member has been developing a design for a flap motor. The particular development has a boundary or may be considered as defining an object, with requirements coming into the object and new design specifications coming out therefrom. This relationship is identified in Figure 17. Thus, as shown in Figure 17, the developer's boundary is illustrated by region 1701. The precedents and constraints are supplied to the flap motor design, illustrated generally at 1702. The flap motor design may be then considered as having sub-assemblies including a processor board 1703, servo motors 1704 and connectors 1705 etc. As shown in Figure 17, the development of the processor board may be divided into software development 1706 and hardware development 1707. Similarly, the servo motors 1704 may be considered with respect to each individual motor, such as motor one identified at 1708. The development of the first motor 1708 may itself be sub-divided into the development of a casing 1709, the development of fixtures 1710, the development of axle fittings 1711 and the development of an electrical specification 1712 etc. These are specified and then passedon as precedents for subsequent development elsewhere.

The existence of the flap motor design 1701 within the global information model 307 is identified in Figure 18. In the global information model of Figure 18, there is the identification of an aeroplane at the very top, identified as 1801. This then is divided into major components including wings 1802, engines 1803 and tail 1804 etc. The flap motor design 1701 constitutes part of the design of the wings 1802 with several layers of subdivision being provided before this particular design element is reached.

Bold indication 1805 connects the design of the flap motor model 1701 to the design model of the fan blades, represented as component 1806, given that it has been found that the operational characteristics of the flap motor may be affected by vibrational characteristics of the fan blades. Thus, the flap motor is sensitive to vibration and the specification must include vibrational constraints, expressed in universally agreed units. The connection with the turbine blades exists because these constitute a major source of vibrational energy and this may be specified in order to ensure that the degree of vibration produced does not exceed the tolerance to vibration for the flap motor and other nearby components. Thus, if a developer attempts to make a modification to the flap motor which affects its tolerance to vibration, the validity of this modification is checked by an automatic link to the definition of the turbine blades and in particular to the definition of the vibrational energy produced. If the flap motor specification results in a tolerance that is incompatible with the degree of vibration being produced, this modification will be treated as invalid and the developer will not be allowed to implement it within the overall system design. It will be appreciated that vibration tolerance of the flap motor may depend critically on certain components. For example, the vibration tolerance of electrical connectors.

The nature of the link between the design of the flap motor and the design of the turbine blades takes account of order and precedence.

Generally, it would be accepted that the design and specification of the flap motor is not as complex as the design and specification of an entire jet engine. Consequently, it is preferable to ensure that the engine is designed first. Therefore there is an order restriction to the effect that it is not possible to design flap motors until the engines have been fully specified. Similarly, the link also maintains precedence to the effect that a redesign of the engine motors may impose new constraints upon the flap motors which may require some reworking of the flap motor design. However, it is not possible for the designer of the flap motor to impose a similar constraint upon the engine design. Consequently, the engine design has precedence over the flap motor design.

In alternative scenarios, it may be undesirable to enforce order constraints rigidly with a precedence constraint being imposed subsequently.

Thus, designs may be initiated with provisional constraints, whereafter verifications are made to ensure that the precedence constraints hold.

Consequently, this may result in some redevelopment of components but the approach is desirable in situations where designs tend not to vary too much from an accepted norm.

Indication 1805, representing the flow of precedence, is maintained by the effect of state machines executed at several sites where development work takes place. Thus, each individual state machine knows whether it has precedence or whether it must be subservient to precedents elsewhere.

Figure 18 represents the structure of the overall global information model but in terms of its actual physical location, the representation of Figure 18 is merely logical. In practice, the structure is distributed over a plurality of sites as indicated in Figure 19. Flap motor design takes place at site 102 with engine design taking place at site 103. These sites communicate via network 108 such that their logical integrity as a structure is maintained, although their physical location is geographically distributed. Thus, communication is effected by means of links having addresses to the locations within the structure in order for the appropriate information to be obtained.

Each site has its own intemal local area network, such as network 1901 at location 102 and the structure itself may interact with other equipment in addition to that provided at group member work stations as shown in Figure 6. Thus, location 102 is provided within plotting and modelling equipment 1902 and site 101 is provided with paper printing devices 1903. Thus, printing devices 1903 are configured to generate statements, reports and instructions etc with respect to the global information model contained throughout the network.

The global information system described facilitates the building of system engineering environments including a complete suite of tools necessary for the construction of the system. This includes the collecting of requirements, the managing of reviews and cost estimation. Thus, within the environment, everything is provided to assist with the development of a project.

The present system provides for the correct structure of information within an information model. In addition, there is the inclusion of precedence of information, where a first development is driven by a preceding development that has precedence; it being impossible to complete the design activity if the precedence were reversed. Thus, the information for the design is combined in the model with a process by which the information is created.

The overall system is programmable to the extent that it is possible to take a basic template and then program it for a particular product life cycle. It is distributed and allows evolutionary development of a system engineering environment. A state diagram is generated that in tum results in the production of an output that may be considered as a requirements document.

The information model and the process model are published, either within an organisation or globally, so that other people can pick them up and exploit them. Consequently, this allows developers to effectively communicate automatically in that they are automatically made aware of the kind of information that is being used along with the present state of the system.

Claims (30)

Claims

1. A method of developing systems over a plurality of development sites, using an information model, wherein said model is represented by a global information structure that comprises a plurality of linked local information structures, comprising the steps of: contributing to a local information structure ; provisionally populating said local information structure with new data; testing the integrity of said global information structure in response to said provisional local data; and updating said local and global information structures in response to said test.

2. A method according to claim 1, wherein said global information model is distributed over a network.

3. A method according to claim 1, wherein a local information structure is initially created by copying an item template.

4. A method according to claim 3, wherein said template includes procedures for making local assessments as to the validity of added or modified data.

5. A method according to claim 3, wherein said template includes links to data fields of other templates in the global model in order to obtain data for testing global integrity.

6. A method according to claim 5, wherein said links are effected by addressing locations over a network.

7. A method according to any of claims 1 to 6, wherein the testing of global integrity includes precedence tests such that a specified data element is required to be consistent with a higher level constraint on which the design of the item is dependent.

8. A method according to any of claims 1 to 7, wherein the testing of global integrity includes an order test such that a data element can be specified only if another element has been specified previously.

9. A method of developing systems over a plurality of development sites, comprising the steps of at a first site, loading a template for an information structure ; and contributing locally to said information structure in accordance with rules defined in said template, wherein said local contribution includes defining at least one link to a local information structure at a second site, substantially derived from said template.

10. A method according to claim 9, wherein said links to other sites define a global data structure for the system.

11. Apparatus for the development of systems over a plurality of development sites using an information model, wherein said model is represented by a global information structure that comprises a plurality of linked local information structures, comprising means configured to facilitate a contribution to a local information structure ; means for provisionally populating said local information structure with new data; testing means configured to test the integrity of said global information structure in response to said provisional local data; and updating means configured to update said local and said global information structures in response to said test.

12. Apparatus according to claim 11, including a serving system for storing said model and a network to provide access to said serving system.

13. Apparatus according to claim 11, including means for copying an item template in order to initially create an information structure.

14. Apparatus according to claim 13, wherein said template includes means for making local assessments as to the validity of added or modified data.

15. Apparatus according to claim 13, wherein said template includes links to data fields of other templates in the global model in order to obtain data for testing global integrity.

16. Apparatus according to claim 15, including means for addressing locations over a network in response to said links.

17. Apparatus according to any of claims 11 to 16, wherein said testing means is configured to include precedence tests such that a specified data element is required to be consistent with a higher level constraint on which the design of the item is dependent.

18. Apparatus according to any of claims 11 to 17, wherein said testing means includes means for testing an order such that a data element can be specified only if another element has been specified previously.

19. Apparatus configured to develop systems over a plurality of development sites, comprising means at a first site configured to load a template for an information structure; and means to facilitate local contributions to said information structure in accordance with rules defined in said template, wherein said local contribution includes defining at least one link to a local information structure at a second site substantially derived from said template.

20. Apparatus according to claim 19, wherein said links to other sites define a global data structure for the system.

21. A computer-readable medium having computer-readable instructions executable by a computer such that, when executing said instructions, a computer will perform the steps of: loading a template for an information structure relating to systems development; receiving development contributions from a developer via a user interface; assessing the validity of said contributions with respect to at least one rule defined within said template; and assessing a remote template over a distributed network by means of data defining a link to said remote template.

22. A computer-readable medium having computer readable instructions according to claim 21, such that when executing said instructions a computer will also perform the steps of linking a plurality of distributed templates to define a global data structure for the system.

23. A computer-readable medium having computer readable instructions according to claim 21 or claim 22, such that when executing said instructions a computer will perform the step of conforming to precedence rules such that design criteria cannot be modified due to another aspect of the design having a higher precedence.

24. A computer-readable medium having computer-readable instructions according to claim 21 or claim 22, such that when executing said instructions a computer will also perform the step of enforcing precedence data so as to impose aspects of the design as having higher precedence over other distributed aspects of the design.

25. A computer-readable memory system having a plurality of data fields stored therein representing a data structure, wherein said data structure includes fields for receiving development contributions from a developer via a user interface; a link to a remote data structure over a distributed network; and executable instructions for accessing the validity of received contributions in response to information derived from said link.

26. A computer-readable memory structure according to claim 25, wherein said structure is initiated by the downloading or installation of a template.

27. A computer-readable memory system according to claim 25 or claim 26, wherein a plurality of links are included to define a global data structure for the system.

28. A computer-readable memory system according to claim 25, wherein said executable instructions perform the step of conforming to precedence rules such that design criteria cannot be modified due to another aspect of the design having a higher precedence.

29. A computer-readable memory system according to claim 25, wherein said executable instructions perform the step of enforcing precedence data so as to impose aspects of the design as having high precedence over other distributed aspects of the design.

30. A method of developing systems over a plurality of development sites substantially as herein described with reference to the accompanying drawings.