Adaptive Car Seat

Table of Contents

3. DISCUSSION AND ANALYSIS3

Driver Selected Seat Position8

4. PROPOSAL PROCESS21

5. CALCULATION PROCESS46

6. DESCRIPTION OF PRODUCTION PROCESS53

END NOTES59

3. DISCUSSION AND ANALYSIS

Humans search instinctively for the body posture allowing the lowest expenditure of energy within the limits of that which is physiologically and biomechanically possible. as well as that which allows an ease and efficiency in task execution (Judie et al., 1993). Driving is. in fact. a task. The vehicle interior should. therefore, be considered a workstation - the driver's seat as one constituent element. The posture ultimately adopted is a compromise between what is good and what is practicaL This fact leads automobile seat system design teams to speak of the posture of least discomfort. It is impossible to quantify automobile seat comfort without first defining a space in which a postural compromise is possible.

The seat adjusters, in combination with the anthropometric characteristics of the occupant, help to define this space. Seat adjustments are supplied to provide some customization of the interior environment to the preferences of the occupant. The minimum set of adjustments for passenger cars is the track. which adjusts the fore-aft position, and recliner, which adjusts the seatback angle. This type of adjustment is necessary to improve not only comfort. but also safety - siuing properly supported and in a relaxed fashion makes me driver more capable of a quicker response. With respect to the previously described seat adjustments, some basic research has already been conducted. Unfortunately, the results are inconclusive.

For example, there is debate as to a required range for track adjustment. Grandjean (1980) recommends a track travel of about ISO mm. This can be contrasted with data collected at the University of Michigan's Transportation Research Institute that suggests 200 nun or more may be necessary to accommodate short and tall drivers (Schneider and Manary, 1991). According to Reed et aL (1994). the seatback recline mechanism should allow torso angles up to 30° (measured from vertical) with a larger range preferred.

Automobile seat adjustment, for the purpose of enhanced occupant comfort. has experienced a rapid introduction of new technologies. For example, Textron's adaptive seat (which is offered as an option on the 1998 Cadillac Seville) offers 8-10 pneumatic and electromechanical adjustments located between the seat structure and soft trim. These adjustments are placed around the bonom of the cushion, lumbar support, and side bolsters. After the ignition is turned on. the seat activates to inflate around the driver gently holding himlher in place. For this feature to be truly beneficial, individual preferences in adjustment need to be understood and accommodated.

BMW has incorporated a different technology, equally impressive in terms of technical content, for some 7-Series models. Called the Active Seat, the technology consists of two liquid-filled containers positioned in the seat base. The containers are alternatively filled and emptied hydraulically to cause a raising and lowering of the right and left sides. This imparts a gentle rocking movement of the pelvis that is said to reduce body ...