Development of a tension-controlled soft-robotic actuation system for a biomimetic bat robot

Abstract

It has been observed that bat species such as the horseshoe bats (Rhinolophidae) that are capable of biosonar-based navigation in dense vegetation deform their noseleaves and pinnae during echolocation. To investigate the impact of these deformations on the encoding of sensory information in the biosonar echoes, a biomimetic robot has been developed to replicate this unique peripheral dynamics. Horseshoe bats have about twenty muscles on each pinna and demonstrate a considerable amount of variability in the motions of these structures. To replicate even a small portion of this flexibility and variability, an actuation mechanism with a small footprint on the deforming structure is necessary. In a prior version of the biomimetic robot, soft-robotic pneumatic actuators were used, but the size of these devices limited their number per pinna and relative orientation. To alleviate these issues, a tension-controlled actuation concept has been developed that consists a bank of servo motors that are connected to the pinna via tendons. At present, this system is designed for five degrees of freedom per pinna and three for the noseleaf. Ongoing work seeks to address how the tension-based actuation system can be controlled to recreate the variability in the noseleaf and pinna deformations of bats.