Insect-Scale Terrestrial Robot Capable of Untethered Environmental Monitoring With Multisensors

Abstract

Here, we present a quadruped crawling mechanism to improve the payload capacity for the power and sensing autonomy of the insect-scale terrestrial robot. The robot with 4.2 cm in length is capable of navigation and real-time environmental monitoring using multiple sensors with an onboard battery. The crawling mechanism is designed based on a shape memory alloy (SMA) actuator for a high force-to-weight ratio, kinematic analysis to generate a near-straight foot trajectory, and force analysis considering the target payload (multiple sensors and battery). Furthermore, we fabricate the robot with simple design modifications allowing for improved load-bearing capacity with minimal weight increase (2.5 times the stiffness for a weight increase of 50 mg). With the high-speed actuation of the SMA, the robot is capable of locomotion at speeds up to 7.21 cm/s (1.72 body lengths per second, BL/s) with 0.23 W of average input power and its maximum payload is 20 g (ten times heavier than the body weight). The demonstration shows that the robot can traverse a confined space (height of 4 cm and width of 7 cm) and monitor the environment through multiple sensors (camera, microphone, and ToF), while operating with all functions for 12 min.