Film sensor for triaxial contact stress measurements on the human body

抄録

Many studies for contact stress measurements on the human body have been conducted using thin and flexible sensors that can be attached to the skin. However, accurate stress measurements, including shear stress evaluations on the contact interface, have not yet been established. This study aims to improve a previously developed thin, flexible sensor capable of measuring three-dimensional vector information, including contact pressure and biaxial shear stress. The previous sensor had an overlapping structure with the upper and lower electrodes. However, the adhesion between the electrode layers was insufficient, resulting in a lack of stability during low-stress measurements. Therefore, a double-sided tape was used to strengthen the adhesion. Furthermore, the electrode shape was revised so that the measurement area of the sensor was downsized and suitable for high integration. The revised sensor was calibrated and found appropriate relationships among contact pressure, shear stress, and output voltage, including the low-stress range. To demonstrate the efficacy of the improved sensor, the sensor was attached to the scapula of a human body. The contact stress acting on the scapula was measured when the backrest of the bed was operated on while the person was lying on the nursing bed. Thus, the change in low contact stress in response to the posture change of the human body on the bed could be measured. The usefulness of the improved sensor was verified experimentally.