Design of Control Systems for Soft Cushions in a Recliner Chair

The aim of this work is the control of a recliner chair with active cushions used to modify the interaction of the human with the chair in order to avoid wound creation on the skin. The cushions are constituted by air-cell actuators positioned in a way to reproduce the high and lower risk zones of the pressure ulcers creation on the human skin. The cushion system, equipped with a real-time pressure mapping with closed-loop control, can identify the critical points on the human skin in order to avoid pressure ulcers creation. The control systems for the single air-cell and for the all cushions are designed and simulated through the software MATLAB/Simulink presenting very interesting results. The novelty of our work is underlined, in particular, by the use of cushions which are designed in line with the higher and lower risk zones of the pressure ulcers generation. In particular, four cushions are designed and controlled: for the head, for the back, for the buttocks and for the heels. All these cushions are used to design a recliner chair which can move from two limits configuration: a bed and a simple chair.