A newly developed chemical locomotory booster for cyborg insect to sustain its activity and to enhance covering performance

Terrestrial insect-machine hybrid robots have long been discussed as alternatives to artificial centimetre-scale mobile robots. These hybrid robots can possess various functionalities (e.g., localization, object detection) by embedding electronic devices while also benefitting from the insects' robust mobility. However, as insects have relatively low walking speed and insensitivity after repeated electrical stimulation, their motion activeness is hard to maintain at a high level. This study attempts to exploit chemical stimulation to boost the insects' walking activity. The use of methyl salicylate as a chemical booster was examined for improving walking activity. The chemical increased the insects' walking speed by 24.3%, which in turn extended their travel distance and region coverage. Also, methyl salicylate still retained the insects' reaction to the electrical induction. By incorporating the locomotory improvements of methyl salicylate with an electrical stimulation protocol, the hybrid robots could reach a terrain coverage speed of 21.6 cm2/s, much higher than only implementing the electrical stimulation (6.8 cm2/s) or no external stimulation at all (1.2 cm2/s). Overall, this is the first demonstration of methyl salicylate's boosting effect on the insects' activity and improving terrain coverage, filling a crucial gap in practical uses of terrestrial insect-machine hybrid robots.