Applied Ergonomics 1977, 8.1, 31-34

The shape of workspace data transformation on a model basis

A. Gedliczka

Department of Environment and Means of Production, Faculty of Industrial Design, Academy of Fine Arts, Cracow, Poland.

Adapting the dimensional structure of a piece of equipment to the physical capabilities of an operator is a typical ergonomics problem. The author describes the trial of a model presentation of the movement abilities of an operator, and a condensed system of notation of spatial data.

Some general points Designing methods for production tools, devices,

machines and workplaces are always concerned with problems of space, defining the spatial structure of the technical equipment within the man-machine system. Basic criteria used in this domain are the movement abilities of the operator and this is a typical problem of ergonomics. Both design and research practice give an idea of certain difficulties that are to be met in this field.

To use the data properly it is necessary for a designer to 'see' the spatial situation in his imagination and to control both the designed object and the arm-reach-range against sometimes conflicting requirements. The control of the design from the viewpoint of operator access may be done by means of either an indirect or direct method. The indirect method requires a reconstruction of the operator's figure or his reach ranges on drawings, using tables, stratification diagrams, etc. The direct method can be used in the case of some more complicated configuration of the object, or the scattering of controls and requires building a model, usually full-scale. It is an expensive undertaking and as the model itself is static it is not easy to assess the operational quality of the design. Anthropometric data for designers are formulated in various ways. They might be listed as follows:

1. Anthropometric data based on typical measurements of the static human body.

2. Data regarding dynamic anthropometry, involving the ranges of movement and presented within two or three planes.

3. Data in pictorial form regarding the anthropometric parameters of the operator and the dimensions of the device together.

4. Data without a picture of man, but presenting direct recommendations for designing certain objects, thus being a closed set limited by the amount of presented objects.

5. There is also a possibility of using only information on the spatial parameters of the operator, omitting the diagram of a nude and often unnatural and funny looking figure of a man beside a machine.

Fig. 1 A subject demonstrating the use of the method to display a maximum reach envelope

Applied Ergonomics March 1977 31

The form of presentation of ergonomic data causes real difficulty and often it is the form of presentation which makes efficient and direct application of the given data in designing impossible. If we aim at the most effective activity, we should treat a designer as the main receiver of the

Fig. 2 The 'normal reach' spatial envelope

Fig. 3 The displacement of the elements at the back of the device, from which measurements may be taken

information. By looking at the tnoblem lr~m~ this poin~ ol view, one can fornmlate a proposition that "1 he informative output ' of ergonomics should be fitted to tile in ti~rmativc input' of a designing system.

It sounds almost paradoxical, but it does correspond to the main ergonomic idea, though in this case the elements of ergonomics may be the object of adaptation. The adaptation may have either a direct or indirect character, the indirect one if we introduce some kind of 'transformer'.

An operative model

At the Faculty of Industrial Design of the Academy of Fine Arts in Cracow, Poland, an attempt was made to construct a model and to elaborate a system of recording the data which would aid the designer in the workplace with regard to the range of arm reaches. It was the basic aim of this study to find a way to project and model spatial values in 1 : 1 scale and then to describe and project them into the scale usually used in designing workplaces, eg, 1:10 or 1:5.

The model was created with limited workshop facilities, in a studio which is designated mainly for didactic activities. That is why the model should be treated as a trial of a method of realization and the first test of the idea, not as the final device.

The model consists of wooden elements 5 x 5 x 100 cm. Each of them is movable back and forth within a range of 85 cm. Thus certain spatial situations can be shaped by the adjustment of the position of each element in the direction perpendicular to the frontal plane. The module of 5 cm used as the module for the co-ordinate system results in certain simplifications but does not change the dimensions in a major manner for most layout problems.

The full dimensions of the device make it possible to obtain the space limits both for the normal reach range and the maximum range for standing and sitting positions. It is suitable for presenting the existing data from tables in full scale. It can also be used for direct tests of reach space for selected segments of the population, eg, 5,50,95 percentiles. By introducing the dimensions of an object being designed it is possible to analyse the appropriateness of the chosen dimensions, ie, to carry out the initial anthropometric research on the basis of a full size model. The device described is to some extent an operative model in that space can be shaped according to various requirements.

Studies concerning the possibilities for using this model are being carried out and one should recognise that it can be used for the analysis of aspects of the viewing field as well.

Figs. 1,2 and 3 illustrate a direct projection of normal and maximum ranges of arm reach in a standing position and the effect of a negative deformation as well.

Fig. 4 The reach envelope obtained from experiments with subjects. The heavy line is the boundary of the matrix of Fig. 5 and the vertical boundary is also an axis of symmetry

System of notation

The next problem arises in the need to find a way of recording the spatial data. The spatial distribution of the points can be described with a system of three co-ordinates.

The layout of the elements of the model evidently suggests the application of the two co-ordinates in order to locate the position of a particular element within a frontal projection. The third piece of information concerning the

32 Applied Ergonomics March 1977

degree of the change of the position of some element is marked on the corresponding square of a diagram as the value of the distance - in centimetres - from the extreme front position (Figs. 4 and 5). In testing spatial ranges, the front edge of the working table can be considered as the extreme front position. Such a concise system of recording data makes possible the projection of all sections, both horizontal and vertical.

1/+0

I}5 5 5 6 4. 3 I

130 1o 9 I0 10 8 3 2

125 14 15 !16 15 14 11 8 6 4

120 !16 18 !19 IS 15 12 8 ? 6

115 17 19 20 19 I? 14- 11 10 ?

110 18 20 20 19 18 16 14- 12 10

105 19 20 20 19 18 17 15 12 10

100 19 20 20 19 18 16 14- 12 9

95 I? 18 18 17 1? 16 14- 12 9

90 16 I? I? 16 16 15 1/+ 11 8

85 1} 16 16 15 15 1/+ 12 10 ?

80 12 I ] 15 15 114 12 10 8 6

75 9 9 10 10 10 10 8 6 4.

?0 I 2 6 6 ? ? 4

Fig. 5 The matr ix developed from the situation shown in Fig. 4. By drawing this on tracing material to the scale of the product drawing, i t may be super- imposed and access dimensions direct ly tested

Fig. 7 A model of the hydraul ic press developed by the method shown in Fig. 6

Fig. 6 A subject engaged in developing the control situation for a hydraul ic press

Fig. 8 The device set up to test the layout and operation of the press shown in Fig. 7

Applied Ergonomics March 1977 33

The system also suggests the possibility of incorporating the information into a computer program, for example, to compare a given spatial arrangement with the information on manipulation areas which could be stored in a computer memory.

In practice, it is possible to use such a 'matrix' (Fig. 5) ....... drawn to the scale required by the designer, put it on the drawing of the product, and recognise directly the degree of agreement between the designed object and the determined reach areas. The figure of an operator is not required. In the case of workplaces at which the operator has to move from place to place, only the distance inwards and the vertical requirements need to be considered.

Remarks on evaluation

Placing controls outside the maximum reach range will mean, for the operator, the necessity of performing manipulations that require a more difficult movement and

a strained working position. Accordingly, tile position oI an operator defines the placing of the controls. An identification of the interdependencies between the posture of the operator and control positions has been catalogued in another project entitled "A catalogue of strained working positions". Since the working position is an important aspect of ergonomic design of workplaces, to achieve a complete estimation of a working space the integration of various criteria, especially the anthropometric and physiological ones, is necessary.

In the suggested system for the study of working space, the recording of physiological variables is possible. The degree of physiological load, both what is preferable and what is acceptable, for a particular element in the space could be measured.

An example of the use of the system to examine the control positions for a hydraulic press is shown in Fig. 6. The operator is reaching to the position of the outer buttons, shown on the small scale model of the machine in Fig. 7. Fig. 8 shows the full scale spatial arrangement of the press, demonstrating how the control areas can be related to the opening for access to the bed.

34 Applied Ergonomics March 1977