A Reconfigurable Backrest Surface for Investigating Preferred Seat Configurations

A reconfigurable experimental seat is useful for seating comfort research and allows researchers to investigate the effects of seat parameters and to propose quantitative guidelines for improving seat comfort. Since 2017, Gustave Eiffel University has such an experimental seat which allows us to carry out parametric studies on the geometric dimensions of a seat and to understand the role of the contact force, particularly that in shear force. Equipped with force and positioning sensors, all contact forces and seat position can be measured. More specifically, it is equipped on the seat with a matrix of 52 cylinders, each adjustable in height and each equipped with a three-axis force sensor. These cylinders make it possible to vary the contact surface of seat pan and measure the distribution of contact forces. More recently, a new system with a matrix of 263 hydraulic cylinders was designed and manufactured to better study the comfort of the backrest in replacement of the three-support backrest. As for the seat pan cylinders, each cylinder for the backrest is also equipped with a force sensor and adjustable in position using a pumping system. The device has two control interfaces, one for the experimenter and the other for the participants in an experiment. We can easily define the same test configuration for all participants. A participant has the possibility of easily modifying the seat geometry using a tablet via an interactive interface according to their preference. The purpose of this paper will be to present the technical specifications of the experimental seat with the new backrest system and its evaluation. This experimental seat could be pivotal especially for improving backrest comfort.