Touching stomach by air

This paper proposes a new endoscope system with an air injection based contact probe capable of measuring the local impedance of the inner surface of stomach. By utilizing air pressure, we can produce an equivalent contact force, which is really advantageous for avoiding any damage for stomach during an examination. A big issue is that there is no way to obtain the applied force to stomach exactly. The key for solving it is the specially designed solenoid valve with the response for more than 500 Hz. The solenoid valve with such a high response allows us to estimate each impedance parameter, even with a reference value. We show experimental system with a couple of interesting results.