An experimental setup to parameterize and simulate upholstered seats

The increasing number of 3D-CAD-systems integrating computer based man models make it possible to evaluate the design of the man machine interface in an early state. The interaction of human and seat is not simulated in a satisfying way yet due to the extreme complexity of the task. At the Lehrstuhl für Ergonomie, Technische Universität München an experimental setup has been developed to investigate this interaction systematically. With the help of this setup upholstered seats can be parameterized by their spring characteristics and geometry to be simulated as physical representation of the seat with the same setup. Pressure distributions and deflection profiles can be measured with integrated sensors. The simulated seat also provides the possibility to vary the seat characteristics systematically. The experimental setup consists of two cushion units, adjustable in size and angle. Each unit consists of 9 by 9 adjustable positioning units, technically realized as programmable springs. Tests with selected positioning units have shown that the accuracy of positioning, as well as the accuracy of the measured and simulated spring characteristics is sufficient. Existing seat cushions have been simulated. Based on mathematical indices the similarity of measured pressure distributions on the simulated cushions and the corresponding seats were compared. Based on this results it can be stated that the characteristics of real seats can be simulated with sufficient accuracy. So it is possible to use the experimental setup as a tool to gain the necessary data to model the interaction between the human body and upholstered seats. Further research is going to be performed on the modeling according to the physical parameters geometry and spring characteristics of the seat as well as the pressure distribution and deflection profiles caused by the subjects interacting with the seat.