Comfort is important in sales of vehicles, seats, airplane and train tickets. However there is no book with an overview of elements important for the design of comfortable vehicle seats. This book supports managers, designers and engineers in designing seats to increase comfort and to reduce discomfort. Both theory and practice in regards to comfortable seats are described. Examples come from Savas Seating, BMW, Boeing, Zodiac, SNCF (French railways) and Long Island Rail Road. The reader is introduced to the latest developments in using 3D scans, human body sensitivity and comfort research methods to optimize seats. Also biomechanics, anthropometrics and ideal posture angles are used as the base for design.
Some authors (e.g. Noro et al., 2005) have also showed that natural movements occur during prolonged sitting as a way to decrease discomfort. With this in mind, it is interesting to consider the ways in which passenger movement can be facilitated in an aeroplane or car seat. Of course, there are difficulties attached to this. When driving a car, for instance, it is unwise to move around too much as we need to pay attention to the traffic. The automobile manufacturer BMW addressed this issue by adding a lightweight massage system (Franz, 2011). The movement pattern of this 60 g pneumatic system (see fig 5.1) was developed in such a way that it does not cause the driver to become drowsy. An experiment involving 20 people driving for approximately two-and-a-half hours showed that activity of the shoulder muscles (m. trapezius pars descendens) was significantly decreased when using the massage system compared with driving without the system. Data were recorded by placing electrodes on the muscles to record muscle tension (electromyography or EMG). Comfort levels were high, and there was no distraction. Also, the pressure on the intervertebral discs (the fluid-filled discs in the spine that link the different vertebrae) varied when the massage system was turned on, indicating that this specific massage pattern promotes fluid transport in the discs, which could have a positive effect on recovery (Franz, 2010). It is important to test the internal results on the body, as the effects of a lightweight system can be very small.
Van Veen et al. (2015) developed another way of creating posture variation by studying the passive movement of vehicle occupants. Posture variation was achieved by continuously varying the angle of the seat pan and backrest within the range shown in figure 5.2. In this study, 21 participants sat on both the moving seat and a static seat. Results showed that comfort and support were significantly better in the dynamic configuration, with participants feeling notably more active, energetic, stimulated, pleasantly surprised, pleased, comfortable, accepting and calm. The static configuration, conversely, left participants feeling marginally more tired and significantly more bored. ×