Among the physical methods of getting necessary predesigning information such as, revelation of discrepancies, study of models and systems tests are most often used.

Method of visual discrepancy revelation is used when it is necessary to determine the ways of machine's perfection. For this purpose the following operations are made:


Then the ways of elimination of the above drawbacks and bringing the design into line with the conditions of exploiting are mapped out. This method can be applied to designing of any objects, construction of which has not been changed for a long time, it is especially useful, when the construction was slightly changed according to exploiting conditions, but it was not thoroughly revised. A bright example of application of this method is analysis of monocycle construction, leading to necessity of its transformation into a motor-scooter./!./

Accumulation and fixation of different factors about studied object take place during application of described and analogical methods.

When enough information is gathered, it is possible to formulate the model of studied object. Further the model is specified and improved. Different classes of models are used for research of designing situations.

The characteristic feature of all models is their conformity only with some sides of a studied object. What properties must a model reflect? It depends on the objectives of modeling and possibilities of the considered class of models.

Among various models of one and the same the process a special class reflecting not only the relations between initial and final values of a process but also all stages of its transformation, can be singled out. In such models there is an inner notion of time, the course of which conforms with the change of successive states of process. Such models are called imitative. The best way of reproducing them is to do it with the help of computer.

Imitative models are widely used in designing farm machinery (FM). Working out systems of machines and their components, modeling different external actions and random factors are carried out on their basis.

Application of these models essentially reduces designing time, lowers cost of works and improves quality of the design plan and specification.

Any model is a result of extracting its certain part from environment. This extracting is carried out on the basis of systematizing features, which are notably, the following; position, structural organization, functional specification. That is why, carrying out full-scale or model tests of an object, it is nec-essary to take these links into account and to estimate the influence of actions not only on the designed or modernized machine, but also on the objects, connected with it.

Such tests are called systemic. Thus, the analysis of motorcycle drawbacks and ways of their elimination leads to the idea of its replacement by a motor scooter. But in this case its is also necessary to evaluate serviceability of roads, distance between filling stations, repair depot, i.e. the systemic tests are required. Full-scale tests would be too long and expensive. Potentialities of modern techniques permit to carry them out on a computer with results close to real.

Systemic tests are advantageous comparing with usage of particular models, calculations and special for each case "problem languages" in those moments, when there are some doubts incorrectness of determination of reasons and consequences in real situation and character of their interrelations. They are also useful when the existing models can't take into account all important interrelations between consequences and reason, which are supposed to be characteristic of a given situation.

Sociological methods obtests are intended for setting feedback between a user on the one hand and designers with manufacturers on the other hand in order to estimate the adopted and realized design. The most widely spread sociological methods are interviewing of users and questioning. Interviewing is necessary for detailed inspection of datum, known only by a user. To carry out interviewing it's necessary to reveal the using situations, relating to an investigated design situation. That's why, while interviewing it is necessary to impel the user to describe and demonstrate any aspect of activity he considers to be important and to direct the conversation to the discussion of moments, having direct relation to the investigated problem. During the condensation both basic and side conclusions are fixed. Comparison of this information with other data is of great use.

Information, accumulated as the result of the interviewing of users, permits the designer to choose the direction of works. As this is a very important moment at the starting stages of designing works, the conclusions, on the basis of which these directions were adopted, should be estimated.

For such evaluation questioning is used. It permits to receive useful information from a large group of users. The first step for achieving this aim is to determine the categories of persons, possessing the required kinds of information; and, in order to identify their knowledge level and to make up a questionnaire, the preliminary separate users questioning is carried out.

Firstly, a test questionnaire for testing the procedure of questioning in a given concrete situation, is prepared. It is tested on a chosen category of persons, answer's are analyzed and questionnaire is specified. Then the specified variant is distributed among the most wide group of users, information is accumulated, analyzed, and the results of both interviewing and questioning are estimated on the basis of acquired conclusions.

The number of non-bibliographic methods of receiving predesigning information is much greater, than it is given in this chapter. But they can be divided into four groups: selective (concrete and realistic); qualitative, depending on time and quantitative, independent of time. Relationship between them is shown on fig.1.4. As it is shown on the scheme, the most important thing is to choose the category. Choosing the way of investigation you should take into account, thr' firstly you must study the general structure of the problem and only after that choose the aspects, which are to be analyzed more carefully.


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