The Modelling of the Interaction of the Human Hand with Products

Many products are designed to be hand operated in use. These extend from industrial machine tools to domestic appliances. In these the designer has to rely upon experience and ergonomic guidelines to ensure that the final product is comfortable, usable and not dangerous when in use. In order to aid in this problem a computer-based manikin has been created to investigate the posture of humans, which now incorporates the movements of the hand. This creates a number of difficulties, which extend from the large number of degrees of freedom to those of redundancy and interaction. In representing such hand movements within a modelling environment it is necessary to firstly understand the natural motions and to then represent then in a realistic manner. Whilst some of the responses are required to form contact with surfaces, to affect a grip or reaction, others are the responses arising from the interaction between the fingers. Other more complex actions require both combinations and sequences of grip actions to achieve the desired action. Many of these actions have been explored in order that the hands of the manikin can be instructed to undertake a range of activities extending from simply that of pointing at an object through to gripping, such as occurs when a manually powered wheel chair is in use.