Bust Stimulation for Sustained Locomotion Control and Autonomous Navigation of Terrestrial Cyborg Beetles

Terrestrial cyborg insects have become a leading candidate for insect-scale robots. These biohybrid systems utilize living insects as mobile platforms while controlling their locomotion via electrical stimulation of sensory organs. Despite remarkable advancement in locomotion control, the deployment of these cyborgs is hindered by their deterioration in locomotory responses to electrical stimulation, which typically involves prolonged, continuous stimuli. This study proposes burst stimulation as an alternative to the conventional stimulation protocol to achieve more sustained responses of cyborg insects from darkling beetles (Zophobas morio). Implementing burst stimulation enhances the sustainability of beetle's responses, with the deterioration rate of the turning response to antenna stimulation reduced by 30%. The induced turning angle is 52% greater under burst stimulation, further advancing locomotion control. The graded response in turning is conserved when tuning the stimulation frequency from 10 to 40 Hz, promoting the integration of burst stimulation into feedback control systems for autonomous navigation of the cyborg beetle. The cyborg beetles are able to reliably and accurately navigate the defined path, with a 73% success rate and 12-mm tracking error. Furthermore, an in-depth analysis of navigation performance suggests that limiting the number of consecutive unilateral stimulations would enhance the efficiency and reliability of the navigation. This study demonstrates that implementing burst stimulation can effectively reduce habituation, improving the reliability, accuracy, efficiency, and sustainability of the control system for terrestrial cyborg insects, advancing the feasibility for real-world deployment.