WO1991000576A1

WO1991000576A1 - Variety control

Info

Publication number: WO1991000576A1
Application number: PCT/GB1990/000969
Authority: WO
Inventors: Charles Roger Mortimore; Raymond Charles Curnow
Original assignee: Exprocad Services Limited
Priority date: 1989-06-24
Filing date: 1990-06-22
Publication date: 1991-01-10
Also published as: AU5856190A; GB9014002D0; GB2234097A; GB8914549D0

Abstract

Means for organising the construction of an article chosen from many similar articles each comprising a combination of a multiplicity of component parts, the incorporation of some of which is optional and the incorporation of others of which is dependent upon part options already chosen, in which, first: (a) there is prepared an ordered total parts list of all the component parts, the incorporation of which might be required for the construction of the article; (b) there is prepared an optional parts list identifying the incorporation of which component parts is dependent upon the incorporation of which other component parts; (c) using both total parts list and optional parts list, there is prepared an actual parts list of which component parts are to be incorporated in the chosen article, no part or group of parts that is dependent upon them presence or absence of one or more other parts being able to be included there within unless the or each other part on which it is dependent has, as appropriate, already been included within or excluded from the actual parts list; and thereafter the article is constructed from the parts identified in the actual parts list.

Description

VARIETY CONTROL

Background to the Invention

The invention relates to the selection and control of the constit¬ uents of a service or a manufactured product. It is capable of application to the design , or organisation , of the construction of an article having a large number of component parts some of which are optional and some of which depend upon previously- chosen optional parts. The article may be any service-supply or artefact involving the selection of large numbers of features , sometimes in dependence upon optional features chosen earlier . The terms "article" , "product" , "supply/supplier" and "feature- component" are to be interpreted accordingly.

It is not uncommon for a supplier to make a product available in a number of variants which are broadly similar , but which differ in the type or nature of certain of their component parts . An example of a product which is often available in a number of variants is the mass-produced motor car , a given model of which may be available with a variety of , for example , engine sizes, exterior paint finishes or standards of interior trim. The "product" could be a supply of goods , services or systems, however, as already indicated .

This sort of product variety arises from the supplier ' s desire to give the customer a wide range of choice . However , a man¬ ufacturer may have other reasons for making a number of var¬ iants of a given product . For example , the supplier ' s ongoing development work may lead to the design of a modified feature for the product , and in order to release the results of this work on to the market, the manufacturer may then use the modified components in future "products " (as defined ) .

Additionally , the supplier may decide to use some of the components present in the existing product range for a new product. Indeed , particularly in the case of products with a large number of component parts , there is rarely such a thing as a "brand new " product, most products being derived from previous models and utilising as many as pc-ssible of the previously engineered components -©f the "proαuctsΛ.

A supplier may ^' also be forced to introduce a modified version of a product in order to meet the , requirements laid down by a regulatory body which can govern the access to a new market. Returning to the example of the mass-produced car, a UK-based manufacturer , wanting to export cars to the United States of America, may need to revise the design of the exhaust system of the car in order to meet the stricter exhaust emission regulations of that country .

Providing a number of variants of a given product can increase the complexity of the tasks of procuring stocks of components for use on an assembly line for the product , distributing the required numbers and types of spare parts needed to maintain the product to dealers , and evaluating the costs of producing the product, in order to be able to make the product available at a realistic price .

Additionally , an order for the product needs clearly to identify which variant is being sought , and in the case of a product which is available in a large number of variants , this almost inevitably involves the order specifying some of the various available features w hich are to be present in the product . In preparing such an order , it is important to specify only those features which are actually available on a variant of the product. Failure to do this can result in the order having to be re-negotiated with the customer , a process which involves delays and disruptions for both the customer and the dealer preparing the order.

From this it will be seen that an important factor affecting the efficiency with which product variants may be produced and sold is the way in which the relationship between any given product variant and its component parts is defined and organised.

The Inventive Concept

Implementation of the afore-mentioned principles requires in¬ itially definitions of options where options is a generic word covering features, parameters or descriptions of aspects of a product. That product may be entirely hardware, entirely software or a sequence of data or any combination, and may be manifested in a variety of physical ways , e. g. on paper as a series of paragraphs, sentences, or coded symbols capable of bearing a unique meaning; stored electronically or electrically or any other recorded form, or as a set of comprehensive engin¬ eering drawings detailing all feasible variants of a hardware product, or as a set of rules and regulations covering some human, social, commercial or other agreed legislatively-covered activity or technological practice, or as agreed best-practice diagnostic procedure to explore any man-made or natural system or combined man-made and natural system including medicine in all its branches , and which gives rise to a sequence of differ¬ ently combined data.

Implementation then proceeds with definition of the links between options, recognising the independence of options via non-linkage and ordered linkage between successive options where such ordered linkage exists. It should be noted that whilst many products --^exhibit full combinatorial tree-structure, many products exhibit very variable tree-structures. In any case it is the intention of this invention to recognise that a full definition of a particular product VBriant or procedural variant or experienced variant requires a comprehensive specification of all options specified in following the specification path of that variant.

It is of- the nature of this process that a such comprehensive specification when fully defined is essentially un-ordered, the implication of each separate sub-specification parameter not necessarily being totally understandable except in the context of the complete specification.

All the effects required can be achieved by grouping all available options into sets of options, whereby inside each set of options any combination, all or none of the options presented within a set may be chosen. As a result of that choice, a further set of options is presented for choice. Such a further set of options may only have been presented as a necessary result of the previous choice(s), or where such necessary consequences of choices have been exhausted, that further set of choices may have been presented not as necessitated by previous choices, but necessitated as an additional independent set of choices in order to complete or further complete the act of total specification.

T© illustrate this process, let us consider a specification string which fully defines a product variant. For this illustration four (4) aspects of the product have to define, aspects A, B, C, D, although the normal ordering associated with the alphabet ABCD Z is of no relevance here, even though there may in some applications be a conventional way of describing aspects, of a product variant, in a particular sequence. Assuming that there are N choices available for each aspect A, B, C, D, although N_A may not be the same as N _B etc, a particular product variant could be represented as A₃ B _j C₂ D_j . However, although conventionally it may be unusual to express a specification in this way, it could be that by making a choice of the B-^ aspect, a consequence of such a choice would be that no freedom of choice is left for the C aspect, in which case C which would automatically be invoked by B_j need not be presented in the context of a set of choices for C.

Indeed, it may in some circumstances be convenient or appropriate to present alongside a set of options the additional option "none of the other options here presented" in order to achieve full logical coverage of the full set of option available at that stage of specification.

In order to meet these requirements, and to achieve maximum economy of representation, provision must be made in the methodology to define, for each set of options numbering N, a minimum N min and a maximum N max of choices which can be made from that set of N. N min can be set to zero, if appropriate, in which case N max >_ 1 ___ N; N min, if positive, can be made equal to N max, both being <N.

However, the linkages and non-linkages between sets of options are critical in deriving the optimal presentation of sequential specification of options in a situation where full combinations of all options is appropriate. It has already been observed that the consequences of a particular option within a set of options may be to obviate the availability/relevance of another set of options, although the consequence of a different option within that same set may be to open up the possibility of that some other set of options being made available. This effect is achievable by nominating as a consequence of taking any specific option the sets of options which will be presented to the specifier (or experimenter in a diagnostic or experimental situation); where multiple options are chosen within a set of options, the individual consequences of each option taken are explored and specified in turn until all consequences of options taken within that set have been explored.

In order to achieve maximum economy of representation, the consequent set of options opened up as a necessary consequence of a given option choice may itself be a subset of a set of options. Such an effect may be achieved e.g. in the following way: a choice A directs you to a choice of a B set of options, but a choice of A may direct you to a B subset of the B options. Such an addressing system affords total flexibility where complex option linkage occurs, such as is required in cross-linked tree structures. It also allows for using such sub-addresses as data to place logical constraints on the admissibility of linkage chains other than the simple Yes No linkages between two individual options.

The implementation of all these requirements can be achieved by holding for each option, the following record of information concerning the option, the set to which it belongs and an appropriate class and sub-class address, and the address whether to a class or sub-class to which that option of chosen leads. Additionally each set is labelled appropriately if it contains options which must be considered independently i.e. not as a consequence of other options having been chosen.

In current computing software science terminology, such a methodology would be implemented by an object-oriented programming system, in that data and procedures are combined in software objects i.e. the option record.

Messages are used to communicate with these objects - in this case the messages are automatically derived from the properties of each object called once the first independent object has been read. Similar objects are grouped into classes.

Data and procedures are inherited through a class hierarchy.

The advantages of such a system are several-fold: objects are separately maintainable, objects are available for re-use, such systems are designed for change in that change is isolable, and there is no limit to the complexity that can be modelled. In addition to these more general properties, the specific implementation as specified above is unique in its minimality of representation.

Given the ability to include or not include options in a set, and the ability to link or not link, it follows that the sequence connectors

.OR., .AND., .NOR., .NAND, are all present in simple equivalents and therefore that full selection and control ability is present in a minimalist and widely applicable format.

Summary of the Invention

In its broadest aspect, for patent purposes, the invention provides means for organising the construction of an article chosen from many similar articles each comprising a combination of a multiplicity of component parts, the incorporation of some of which is optional and the incorporation of others of which is dependent upon part options already chosen, in which, first:

1) there is prepared an ordered total parts list of all the component parts the incorporation of which might be required for the construction of the article; 2) there is prepared an optional parts list identifying the incorporation of which component parts is dependent upon the incorporation of which other component parts;

3) using both total parts list and optional parts list, there is prepared an actual parts list of which component parts are to be incorporated in the chosen article, no part or group of parts that is dependent upon the presence or absence of one or more other part being able to be included therewithin unless the or each other part on which it is dependent has, as appropriate, already been included within or excluded from the actual parts list;

and thereafter the article is constructed from the parts identified in the actual parts list.

Most conveniently this methodology is implemented using an appropriately programmed computer, in which case, in another broad aspect, the invention provides a computer in combination with a programme which is loaded into the computer such that, in use, the computer performs some or all of the steps of a method of preparation a specification of features, which features are selected, in sequence, from a number of sets of possible features for the specification, the method comprising the steps of:

1) providing that the following information is present in the computer memory: a) for each feature which may be selected for the specification, information identifying both that feature and the prospective set in which that feature is placed,

b) for each feature, control information establishing whether or not the availability of the feature for the specification is dependent on the presence or absence in the specification of any relevant features or combinations of features, and

c) for each feature which is so dependent, conditional information identifying the relevant features or combinations of features;

2) ensuring that, if present in the specification, the relevant features or combinations of features, on which the availability of a feature is dependent, are selected before the dependent feature;

3) selecting one or more features from a set;

4) in accordance with the control and conditional information, determining which features of the next set are available for selection for the specification;

5) selecting one of the available features from that set; and 6) repeating steps (2) to (6) for all the remaining sets.

Examples of applications of the Invention

Example 1

In this application, the invention provides a computer which is so programmed as to prepare a specification for an electric motor, the features of the specification being the various motor components. One set of features may be of the possible frame sizes that the motor may have (see for example Table 1) whilst another set is of the possible core length of the motor armature (Table 2). Some core lengths cannot be accommodated in certain frame sizes, and the availability for selection of those core lengths is therefore clearly dependent on which frame size has already been selected.

TABLE 1

Set Code Set Description

•p _S Frame Size

■pgL Core Length _jjgg Basic Design

JJJJ Enclosure

_BV1 Basic Vent Format g_j D/E Bearing Type _j^. Is Flange Required _FLj Flange Type p_LH Flange Holes Required _os? D/E Oil Seal Required

etc.

The control and conditions in respect of the core lengths may specify, for example, that the largest core length is only available for selection if the largest frame size has already been selected. If the largest frame size has not been selected, the largest core length will not be made available for selection as a feature of the specification - but of course, the smaller core lengths will be made available.

Members of other sets of features for the motor may be dependent upon certain features not having been previously selected.

Therefore the conditional information for each feature which is dependent upon earlier selections will both identify the earlier selections and specify whether the availability of the feature is dependent upon the presence or absence of those earlier selections.

In the case of the electric motor example, with the inventive method being implemented on a computer, the computer will, in use, start by displaying to the operator the various frame sizes that the motor can have. Once the operator has selected the required frame size the computer will then display the next set of features, i.e. the various core lengths, excluding the core lengths which are not available for the particular, selected, frame size;

For example:- Option FRLD is only available for FRSA or FRSB.

FRLE for FRSA

FRLF for FRSG

This process - display a set, make a choice, display the next set (modified as necessary by any or all of the preceding choices) - is then repeated until all the necessary selections have been made.

As will readily be appreciated, the sequence in which these sets are displayed must be such that, for each feature which is dependent upon the presence or absence of other features, the sets in which those other features are placed must, with appropriate exclusions, have already been displayed.

The selection of features may be made manually, but if - in the light of previous selections - a set has only one available feature, which must be included in the specification, then in a computer implementation that feature may be automatically selected by the computer, which then displays the next set (with appropriate exclusions). In some sets, the features may in fact be the absence of certain components or types of components in the motor, and thus specifying that a feature should not be present in the motor is, in itself, treated as a selection of a feature. Once all the sets have been displayed in this way, the computer prepares a specification identifying the variant of the motor required by the customer.

The computer may be programmed using a suitable database, management system. This entails setting up a number of data files holding the required information on the possible features of the motor, and a command file which permits an operator to access or interrogate the data files, and which causes the computer to present for selection only those features which are, at the relevant point in the specification-preparing process, still available for selection.

The data files contain the following information:

Information identifying the sets of features (referred to as Option Sets) - Table 1 above;

Information identifying the features within those sets, and the control information establishing whether or not the availability of those features is dependent on any other selection (referred to as Product Definition); - Table 2 above; and

Conditional information identifying the relevant previously selected features or combinations of features (referred to as Dependencies Definitions) - Table 3 immediately below.

TABLE 3

Dependencies Definition

Example 2

Associated Features Database

The system output is a textual string of qualifiers which can be transferred into a database. Within this database the correct sub- systems are collected after matching of the qualifiers and a complete specification produced.

The structure of the database has to be such that sub functions are only retained once and that the extension of functions is purely additive. The application of choices can be applied to any problem of configuration. The following example of a salt and pepper pot has been chosen because it is a tangible everyday problem of variation of configuration. Figures 1 and 2 of the drawings illustrate it.

The salt and pepper pot illustrated fulfils two functions by the very nature of the product they handle i.e. salt and pepper. The sub functions are identical except for the one which actually handles the grinding and dispensing of the condiment.

The following table shows in a descriptive method the way which the two products would appear as a list of sub functions or as many would consider piece parts.

1 2 3 4 5 6 7 8

Notionally the same but because of the different consistency of salt and pepper, item 5 and 6 in each case are very different. Therefore we have two lists of functions or in this case parts.

If a further function, say Grips to the top, is added by an alternative additional part then the number of models is doubled. Add a colour to the body and the number is double again. The traditional representation of the structure of parts would be as follows. It can be seen that common parts or functions repeat themselves across the columns.

To simplify the database the parts list would be better expressed as:-

Thus by following the product description down the column, the structure of parts can be assembled.

System will output, as already stated, the string of qualifiers which will specify the product. The parts list could be stated as follows, if the logic of additional model is pursued and the table is re¬ constructed.

With the look up columns on the right hand side of the list of sub¬ systems the recreation of the engineering parts list 'without joins' is part of the feature.

On the left hand side of the list of sub-systems the column for qualifier from system allows the creation of a specific model on the fly. Example 3

This illustration shows a computer-based example of the application of the methodology of the invention in the commercial world, in this case insurance. Figures 3, 4 and 5 illustrate it.

Figures 3 and 4 show typical "choice" screens, and

Figure 5 shows a database structure underlying the same system.

Claims

CLAIMS:

1. Means for organising the construction of an article chosen from many similar articles each comprising a combination of a multiplicity of component parts , the incorporation of some of which is optional and the incorporation of others of which is dependent upon part options already chosen, in which . first:

(a ) there is prepared an ordered total parts list of all the component parts, the incorporation of which might be required for the construction of the article ;

(b ) there is prepared an optional parts list identifying the incorporation of which component parts is dependent upon the incorporation of which other component parts ;

(c ) using both total parts list and optional parts list, there is prepared an actual parts list of which component parts are to be incorporated in the chosen article , no part or group of parts that is dependent upon the presence o r absence of one or more other parts being able to be included there within unless the or each other part on which it is dependent has , as appro- priate , already been included within or excluded from the actual parts list;

2. A computer in combination with a programme which is loaded into the computer such that , in use , the computer performs some or all of the steps of a method of preparing a specification of features , which features are selected , in sequence , from a number of sets of possible features for the specification, the method comprising the steps of :

l) providing that the following information is present in the computer memory:

(a ) for each feature which may be selected for the specification, information identifying both that feature and the prospective set in which the feature is placed;

(b ) for each feature , control information establishing whether or not the availability of the feature for the specification is dependent on the presence or absence in the specification of any relevant features or combinations of features , and

( c ) for each feature which is so dependent, conditional information identifying the relevant features or combinations of features;

2J Ensuring that, if present in the specification, the relevant features or combinations of features , on which the availability of a feature is dependent, are selected before the dependent feature ;

3 Selecting one or more features from a set;

4^") In accordance with the control and conditional information, determining which features of the next set are available for selection for the speci¬ fication;

5 Selecting one of the available features from that set; and

b) Repeating steps ( 2 ) to ( 6 ) for all the remaining sets .

3. A methodology substantially as described herein with reference to any of the described Examples .