Abstract: Obstacle avoidance is of great importance for mobile robots since it provides protection for the robots’ safety and ensures their routine operations. Sensors are proven to play an important role in robots obstacle avoidance, and they are useful as well. However, more sensors indicating additional space, larger weight load and more energy consumption. Reducing unnecessary sensors is conducive to the development of mobile robots and remains promising. Here we demonstrate Sensor Free Obstacle-Passing Robots (SFOPRs) inspired by flies using the Obstacle-passing strategy instead of Obstacle avoidance. The ability to autonomously adjust its direction after hitting obstacles and the ability to continuously hit obstacles are 2 key problems that need to be solved to build this robot. Owing to arc-shaped head design and undulating motion behaviors, the robots can autonomously adjust their direction to the outline of obstacles, such as a 90o corner, dispersive irregular obstacles, and even an “S” type channel without the assistance of any sensor. Besides, the caterpillar-like movement enables robots to continuously hit obstacles. Furthermore, collaborative awareness and mutual aid can be realized among two or more prototype robots, indicating simple yet functional units for future swarm robots. This study could provide a new strategy to pursue sensor-free obstacle-passing robots for future swarm robot applications.

Key words: Bioinspired , · Sensor , · Obstacle , · Swarm robots , · Untethered