With the evolution of Autonomous Vehicles for the near future, BMW has designed a new seat for their vehicles, whose aim is to offer the greatest amount of comfort possible. Their main challenge now is to transform this level of comfort even when passengers want to sleep on the road, or while charging their vehicles. When it comes to confined spaces such as seats, obtaining a comfortable sleep has always been a challenge.

Taking into account the difficulty in achieving comfortable sleep in a seat, one of the main goals of BMW is to further enhance this seat within the context of sleeping. Sleeping is becoming one of the most popular activities among those passengers during a journey, and it is expected to grow with the integration of fully autonomous vehicles. Therefore, the first goal of the project is to analyze the seat to ensure maximum comfort when sleeping, and the second goal is to tackle the main area of discomfort with a design proposal.

For this, a thirty-minute sleeping research is conducted with sixteen participants, evaluating two different backrest angles (120º and 140º). The results show a preference of reclined backrest of 140 degrees, and an increase in comfort compared to sleeping in conventional seats. All participants had a good nap with this reclination, with an average amount of sleep of fourteen minutes. Regarding the seat analysis, the most uncomfortable part of the seat is the headrest, due to the lack of support for neck and head, and the lack of height adaptability to different demographics. The second area of discomfort is the leg support and the lack of footrest.

With these results in mind, the second goal is to develop an attachable head support that can be integrated in the BMW seat, for offering more comfort while sleeping in a reclined position. The main requirement considered is to make it adjustable in the area of head, neck, and height of the user.

The proposed design consists of two main components: a head support and a neck support. An integrated mechanism in the foam allows the adjustment of both to the width of the head and neck. In addition, a mechanism allows adjusting the height of the support to the desired position. Different prototypes are developed to assess the viability of the design features and feasibility for its integration in the seat.

A subsequent user test involving ten participants is conducted to validate the comfort and functionality of the design. The participants were asked to sleep in the seat making use of the new support. In order to obtain more objective results, four pressure sensors are integrated in the product to calculate the ideal pressure distribution exerted by the users. The data obtained from the sensors corroborated findings from literature research. Additionally, the support significantly increases the comfort after a thirty-minute nap in comparison to sleeping without support.

Taking a nap is a welcome pastime in vehicles such as trains, airplanes, and cars. Flat sleeping cannot always be facilitated because of space and economic constraints, but a larger backrest recline angle is associated with better sleep quality. To define the best and the worst comfort experience and sleep comfort in these settings, and to offer design guidelines to practitioners, six backrest recline angles were compared regarding overall comfort and sleep comfort. The backrest recline angles ranged from 110 to 150 degrees, and 180 degrees was added as a reference. 16 participants were invited to sleep for a duration of 90 min. in each condition. Overall comfort and sleep comfort significantly improve in conditions higher than 120 degrees. Local discomfort is rated relatively low in all angles, but in comparison, people experience high discomfort in the neck, lower back, and lower leg region while in the 110 and 120 degrees condition. It is concluded that in the bigger recline angles the napping comfort experience is higher, with a minimum advised angle of 130 degrees.@en