Investigation of obstacle avoidance algorithm in paired-driving autonomous mobile robots revealed by mimicking ultrasonic sensing in bats

To evaluate the biosonar behavior of bats in paired flight from an engineering point of view, obstacle avoidance driving experiments were conducted using two autonomous mobile robots embedded with one ultrasound transmitter and two receivers. It has been reported that when two bats aim at the same prey simultaneously, the following bat temporarily stops the pulse emission and tracks the preceding bat. It is supposed that this is to avoid interference with signals by other individuals, i.e., utilizing pulses emitted by other individuals and the echoes for their own sensing. Then we proposed the hybrid sensing which switches active and passive sensing according to the situation, and the completion rate of obstacle route in the paired-driving robots was examined. As the result, it was proven that hybrid sensing robot reduced the emission frequency of the pulse, but the completion rate of the obstacle route was high in comparison with case of the paired-driving robots with active sensing. In addition, in order to improve localization performance and to emit FM type ultrasonic pulse of bats, thermoacoustic transducer (thermophone) with broadband frequency characteristics are introduced as a ultrasound transmitter. [Work supported by JSPS-KAKENHI;JP18H03786, JP16H06542 and JST-PESTO.]