Inferring Environmental Interactions of Soft Everting Robots From Acoustic Signals

Acoustic signals can be used to detect environmental interactions of everting tube robots. This experiment distinguishes differences in pressure and audio signals in tubes freely everting through different-sized tunnels, with acoustic signal measurement ranging from 0–10 kHz. Pressure rises when transitioning to smaller tunnels and drops when transitioning to larger tunnels. Audio becomes louder when transitioning to larger tunnels and quieter when transitioning to smaller tunnels. Audio FFTs and spectrograms also show distinguishable eversion sounds and clear evidence of tunnel transitions. Time data suggests that reliable time series models could be created to detect tunnel transitions. Frequency data also suggests that a reliable image-analysis model could be created to detect tunnel transitions.