Contact Point Estimation along Air Tube Based on Acoustic Sensing of Pneumatic System Noise

Active acoustic sensing is being widely used in various fields, with applications including shape estimation of soft pneumatic actuators. In a pneumatic system, air tubes are frequently adopted, and thus it is essential to detect failures along the air path. Although acoustic sensing has been used for detecting contact and identifying the contact position along a tube, it has not been applied to pneumatic systems. We devised an acoustic sensing method to this end for air tubes in a pneumatic system. As pneumatic system noise propagates through the air tube, we employed this type of noise instead of the conventional method of using a sound source or emitting vibration with an additional oscillator. We conducted several experiments that confirm the feasibility of the proposed method, succeeding to estimate the contact point on a 16 m air tube.