We propose a design and control of an air pillow system (IAAP: Impedance Adjustable Air Pillow), in which users can independently adjust its height and tactile sensation. The IAAP consists of a pressure sensor and a motor-driven piston-cylinder mechanism and an air bag. Because the IAAP does not contain any mechanical sensor and actuator inside the air bag, by using only the air pressure and the piston position, we propose an open-loop based impedance control method to set the target mechanical impedance of the air bag. To evaluate the basic validity of the proposed method, impedance setting tests have been conducted. To evaluate the usability of IAAP comparing with some commercially available passive pillows, sensory evaluation tests have been carried out on a group of subjects. As a result of these tests, we conclude the IAAP has a practical potential as a high-performance pillow.
