Design and Control of a Reclining Chair with Soft Pneumatic Cushions

The object of this work is the control of a reclining chair with active cushions used to optimize the interaction of the human with the chair and to avoid the formation of sores on the skin. The cushion system, already presented in other works, consists of air-cell actuators distributed according to the risk that pressure ulcers on the skin can be generated in certain areas. In this work, four cushions are designed and controlled for four parts of the human body: 1) head; 2) back; 3) buttocks; 4) heels. Cushions are used to design a reclining chair that can be moved between two configuration limits: a) chair; b) bed. The four cushions can provide real-time pressure mapping with closed-loop control, which allows to identify critical points on the body surface where pressure ulcers could form. The control systems for the single air-cell and for all cushions are designed and simulated using the software MATLAB/Simulink, presenting very interesting results.