A Tool for the Assessment of Inter-Segmental Angular Relationships Defining the Postural Comfort of a Seated Operator

The design of vehicle compartments and seats can be improved and facilitated by a more thorough knowledge of users' needs and functional characteristics from which models and criteria can be developed.

With the objective of building a geometrical model of human body permitting to evaluate a seated operator's postural comfort on the basis of biomechanical criteria, a methodology to analyse posture variability in relation to seating conditions has been worked out.

The main tool of this method is a laboratory experimental device composed of a seat, a foot-rest and a steering-wheel, enabling to adjust the seating posture through 12 motorized adjustable supports which can be directly controlled by subjects. With this device, the seat-back longitudinal profile can be modified and the sagittal shape can be measured. A preliminary experiment was performed to test the relevance of these adjustments and the flexibility of this device; its results show that postures chosen by an individual in a given situation are reproducible.