Abstract
Insect-computer hybrid robot, often referred as to 'Cyborg Insect', is the fusion of living insect and miniature radio-enabled wireless electrical stimulator to control the locomotion of the insect platform in walking and flight. The miniature stimulator is mounted on the back of the living insect and metal thin wires are implanted into neuromuscular sites of our interest to electrically stimulate for eliciting experimentalist's desired motor actions and behaviors.
Insects exhibit amazing modes of locomotion. They float, swim, crawl, jump, run, fly and they even walk on water. They do this with such efficiency, sophistication and elegance of function across a vast size range that they have mastered locomotion on almost every terrain on the earth. Very recently researchers have started building ultra-small data recording systems for flying insects and tried to stimulate insects (moths, locusts, beetles) to induce desired actions.
The miniature stimulator (~1.3 g in total mass) consisted of a custom PCB (printed circuit board), an off-the-shelf microcontroller, a rechargeable micro battery and thin-wire electrodes. We employed Mecynorhina torquata, a giant flower beetle as the insect platform for the hybrid robot (10 g, 6 cm, 3 g payload capacity in flight). The stimulator assembly was mounted on the beetle's pronotum and the terminals of wire electrodes were inserted into the optic lobes, brain, basilar flight muscles and dorsal thorax (counter electrode).
Flight initiation was triggered by applying 2 - 4 V, 100 Hz, 20 % duty cycle, biphasic square pulse trains between the two electrodes implanted into the optic lobes, massive neural clusters of compound eyes. Cessation was triggered by a single DC pulse applied to the same sites as the initiation. The wing power was decreased (and thus throttle down) when the same 100 Hz pulse trains were applied to the brain. Turnings were elicited by applying the same pulse trains to either the left or right basilar flight muscle. The beetle turned in opposite direction to stimulated side: left turn was, for example, conducted by the right side stimulation.
On the other hand, toward a self-powering unit for the insect-computer hybrid robot, we have proposed a miniature biofuel cell implantable into living insect to generate electrical energy by consuming energy source, for example, saccharide. For that we have developed nanoparticle catalysts for oxygen reduction reaction such as P or B doped Pd, denoted by Pd-P or Pd-B. By doping these non-metal elements into Pd, the catalytic activity of Pd was drastivally enhanced. These Pd-P and Pd-B catalysts were facilely synthesized by a electroless deposition process using hypophosphate and DMAB (dimethylaminoborane) as reducing agent, respectively.
In the presentation, we will show the demonstration of insect locomotion control and the experimental data and discussion on the enhanced catalytic activities of the Pd nanoparticle catalysts.
Figure 1