Fig. 5: E-Antenna (centimeter-scale) enabled mobile robots to achieve insect-like vision-free wall-following navigation in the dark environment.

A-i Schematic of tactile-based navigation in the dark environment, the E-Antenna serves as a supplemental perception source of vision in the dark environment. A-ii Two E-Antennas (2 mm in diameter and 20 mm in length) were mounted on both sides of a mobile robot to functionalize it with tactile perception ability. B Photography of insect-like vision-free wall-following navigation experiment of a small mobile robot with two E-antennas mounted on its forehead, where COG is center of gravity and \(\theta\) is the steering angle. C The trajectory of the mobile robot (red line) during its wall-following navigation process and the wall’s serpentine outline (black line), where the moving trajectory of the mobile robot is consistent with the wall’s outline. D The mobile robot’s steering angle (labeled as red) indicates that the robot dynamically adjusts its moving direction to keep following the wall guided by the E-Antenna. E The raw sensing output of the E-Antenna remains stable upon contact with the wall. F The distance between the mobile robot and the followed wall, where the distance fluctuates within a small deviation of 2.04 mm (0.048 times the robot width).