Efficient Autonomous Navigation for Terrestrial Insect-Machine Hybrid Systems

While bio-inspired and biomimetic systems draw inspiration from living materials, biohybrid systems incorporate them with synthetic devices, allowing the exploitation of both organic and artificial advantages inside a single entity. In the challenging development of centimeter-scaled mobile robots serving unstructured territory navigations, biohybrid systems appear as a potential solution in the forms of terrestrial insect-machine hybrid systems, which are the fusion of living ambulatory insects and miniature electronic devices. Although their maneuver can be deliberately controlled via artificial electrical stimulation, these hybrid systems still inherit the insects' outstanding locomotory skills, orchestrated by a sophisticated central nervous system and various sensory organs, favoring their maneuvers in complex terrains. However, efficient autonomous navigation of these hybrid systems is challenging. The struggle to optimize the stimulation parameters for individual insects limits the reliability and accuracy of navigation control. This study overcomes this problem by implementing a feedback control system with an insight view of tunable navigation control for an insectmachine hybrid system based on a living darkling beetle. Via a thrust controller for acceleration and a proportional controller for turning, the system regulates the stimulation parameters based on the instantaneous status of the hybrid robot. While the system can provide an overall success rate of ~71% for path-following navigations, fine-tuning its control parameters could further improve the outcome's reliability and precision to up to ~94% success rate and ~1/2 body length accuracy, respectively. Such tunable performance of the feedback control system provides flexibility to navigation applications of insect-machine hybrid systems. Keywords Biohybrid systems; Insect-machine hybrid systems; Zophobas morio; Autonomous navigation; Feedback control; Path-following 1. Introduction Terrestrial insect-scale mobile robots have become prominent candidates for post-disaster search-and-rescue missions. Their tiny size and light weight would help them easily penetrate deep into the rubbles of collapsed buildings without causing additional collapses. While there are growing efforts to achieve insect-level autonomy in these robots, it is still a challenge to match their natural-born counterparts, i.e., living ambulatory insects. While control autonomy was achieved in various insect-scale mobile robots (Chen et al. 2020; de Rivaz et al. 2018; Goldberg et al. 2018; St. Pierre and Bergbreiter 2019; Yang et al. 2020), power autonomy was demonstrated only in a few platforms, like HAMR-F (Goldberg et al. 2018) or Robeetle (Yang et al. 2020). Furthermore, although inverted and vertical climbing was demonstrated (Chen et al. 2020; de Rivaz et al. 2018), maneuvering across complex terrains is still a conundrum for these artificial robots.