This paper is based on a study  which has been carried out by the Institute for Engineering Design and Industrial Design (IKTD), Department Industrial Design Engineering and completed by further aspects regarding haptic perception.
Among other things, industrial design engineering deals with human product relations. Starting from the designed product and, respectively, the product gestalt, consisting of the sub-gestalts: assembly, shape, colour and graphics, it is at first perceived by human. An identification process is activated in the human brain by the types of perception: vision, hearing, feeling, smelling, tasting and others. This identification causes a certain human behaviour and, for this reason, a special operation and use of this product .
Each type of perception has different perception performances and, respectively, information gathering which is highest when seen by the sense organ ‘eye’. The tactile or haptic perception performance by the skin is approximately 4 × 105 bit/s . To ‘feel pressure’, ‘feel roughness’, ‘feel position’, ‘feel movement’, ‘feel heat’, ‘feel humidity’ and ‘feel electrically’ are tactile or haptic perceptions.
The haptic design of a handle is tested by means of a cordless screwdriver (see Fig. 1). Characteristic handles of power tools must be designed according to the hand geometries of different users. In reality, this is unfortunately not always feasible, since technical restrictions, as, for example, the integrated switch and the inserted neck of the battery pack do not allow this. The aim of the study is the variable adaptation of the outer handle contour to the individual operator’s hand.