Developing small mobile robots for Urban Search and Rescue (USAR) is a major challenge due to constraints in size and power required to perform vital functions such as obstacle navigation, victim detection, and wireless communication. Drawing upon the idea that insects’ locomotion can be controlled, what if we further utilize the insects’ intrinsic ability to avoid obstacles? Herein, a cockroach hybrid robot (≈ 1.5 cm height, 5.7 cm length) that implements the abovementioned functions is developed. It is tested in an arena with randomly placed obstacles, and a motion capture system is used to track the insect's position among the untracked obstacles. A navigation algorithm that uses an inertial measurement unit (IMU) is developed to heuristically predict the insect's situation and stimulate the insect to escape nearby obstacles. The utilization of insect's intrinsic locomotor ability and low‐powered IMU reduces the onboard power load, allowing the addition of a human‐detecting function. An image classification model enables the use of an onboard low‐resolution infrared camera for human detection. Consequently, a single hybrid robot is established that includes locomotion control, autonomous navigation in obstructed areas, onboard human detection, and wireless communication, representing a significant step toward real USAR application.

In this study, a biological microactuator was demonstrated by closed-loop motion control of the front leg of an insect (Mecynorrhina torquata, beetle) via electrical stimulation of the leg muscles. The three antagonistic pairs of muscle groups in the front leg enabled the actuator to have three degrees of freedom: protraction/retraction, levation/depression, and extension/flexion. We observed that the threshold amplitude (voltage) required to elicit leg motions was approximately 1.0 V; thus, we fixed the stimulation amplitude at 1.5 V to ensure a muscle response. The leg motions were finely graded by alternation of the stimulation frequencies: higher stimulation frequencies elicited larger leg angular displacement. A closed-loop control system was then developed, where the stimulation frequency was the manipulated variable for leg-muscle stimulation (output from the final control element to the leg muscle) and the angular displacement of the leg motion was the system response. This closed-loop control system, with an optimized proportional gain and update time, regulated the leg to set at predetermined angular positions. The average electrical stimulation power consumption per muscle group was 148 µW. These findings related to and demonstrations of the leg motion control offer promise for the future development of a reliable, low-power, biological legged machine (i.e., an insect–machine hybrid legged robot).

Cyborg insect also referred as insect-machine hybrid robot, consists of a living insect platform and an electronic backpack mounted on. The small size and magnificent walking ability of the insect make this hybrid system a potential candidate for search and rescue missions. The great locomotory capability helps the insect to cope with the complex and unpredictable terrains, whereas the tiny dimension allows it to easily enter the debris of post-disaster sites. There is a necessity to establish more controllable mobility for cyborg insects to develop more efficient maneuver plans. Here, this study demonstrates the control of sideways and forward walking in a cyborg beetle by emulating the touch responses of mechanoreceptors on the insect’s elytra using the electrical stimulation. The beetle walked sideways leftward when the right elytron was stimulated, and vice versa. The forward control was attained by stimulating both elytra simultaneously. In addition, these elicited motions were found to be graded by tuning the stimulation frequency as increasing the frequency sped up the sideways walking and slowed down the forward velocity. Besides complementing the controllability of the cutting-edge cyborg insects, this graded response is essential for improving the navigation in cyborg insects for search and rescue missions.