Development of thin and flexible contact pressure sensing system for high spatial resolution measurements

Abstract Evaluations of stress applied conditions are important for a diagnosis of human joint diseases. Measuring contact pressure distributions at the interface area of small joints such as finger joint surfaces is difficult due to the spatial limitation of sensors. Two contact pressure sensor units have high spatial resolution of 90 μm with 24 × 24 and 128 × 128 measurement points were developed in this study. The system accuracy was quantitatively confirmed by measuring the pressure distribution pattern during a cylindrical-shaped punch impressed on the sensor. The measured pressure distribution agreed well with the theoretical compression pattern. The contacting area was recognized as 110% of the actual cross-sectional area of punch, and the total force value calculated from the integration of pressure distributed over the contacting area was 93% of the applied force. Moreover, a complex pattern of coin surface was obtained as the pressure distributions in this sensing system. As an application, the sensor was inserted to a small joint part in chicken wing for pressure measurements at the interface. The possibility of measuring the dynamic change of pressure distribution at narrow joint space was shown in this study.