Modeling and Experimental Investigation of the Maximum Stresses Due to Bending in a Tubular-Shaped Artificial Skin Sensor

High flexibility skin-like sensors, such as electrical skin (e-skin) sensor for pressure measurement, have the potential to provide quantitative physical assessments and protection for human life. One promising application is to monitor the contact pressure of a colonoscope to the colonic wall during a colonoscopy to prevent perforation and hemorrhaging. Many attempts have been made to fabricate highly stretchable electronic devices. However, no effort has been made to investigate the mechanical behaviors of a tubular-shaped e-skin when bent, which is a typical working condition of such a sensor when attached to a colonoscope. The sensor should measure no pressure without external compressive force. However, bending of the sensor will generate measurable pressure, which is no use to doctor's diagnostic and causes disturbance to the doctor. This paper aims to compensate this false positive error to improve the sensor's reliability and accuracy. Based on a tubular-shaped, highly flexible skin-like sensor array we developed, we conducted both modeling and experimental studies on the change of the maximum pressure distribution of a tubular e-skin sensor under various bending conditions with and without external compressive force. This paper revealed the value of the maximum stress on a tubular-shaped e-skin sensor array when bent. The measuring errors due to bending in pressure detection during colonoscopy can be quantified for compensation. Thus, high accuracy diagnose can be achieved. These results could also be potentially used to address strategies on optimizing tactile sensor design for other medical applications.