Researchers in the United States have developed an underwater robot capable of ascending, descending, moving forward, moving backward, and even rotating on its own axis—all controlled by just two actuators. This invention was presented by engineers from North Carolina State University in a study published in the scientific journal Science Advances.
The robot was inspired by a marine animal known as a feather star—a relative of the starfish—which uses flexible arms to swim and change direction with grace. It was precisely this characteristic that the researchers sought to replicate. The device features four flexible, wing-like structures connected to a central body; rather than installing an independent motor for each joint, the engineers developed a pneumatic mechanism that uses air pressure to actuate these structures.
The secret lies in the shape of the wings, which store elastic energy when deformed and then snap back to their original position. Through this design, the researchers were able to replicate three distinct modes of fluid underwater locomotion. During experiments, the robot also demonstrated practical applications: equipped with a small camera, it successfully explored narrow underwater spaces, while other versions were used to lift objects and work collaboratively to remove debris.
This innovative aquatic device stands out for its versatile movement, as it can switch between different locomotion patterns depending on mission requirements. For instance, in "jellyfish mode," the robot moves its four limbs simultaneously with elastic strokes to achieve a stable vertical ascent; in "fish mode," it uses one of its arms as a rudder to turn laterally; and by activating its channels sequentially with a time offset, it enters a "rotor mode" that allows it to spin on its own axis while continuously gaining altitude.
Beyond its fluid, three-dimensional maneuverability, the prototype has demonstrated significant practical potential for underwater cleaning and maintenance tasks. Equipped with a small magnetic patch or hooks on its underside, the automaton can efficiently collect metallic debris—such as rusted screws—or handle plastic containers from the seabed in a matter of seconds. Furthermore, it is capable of working collaboratively with other robots in a swarm to lift heavier loads, opening the door to future applications in ocean preservation.
The technology is still in the development phase, and engineers plan to create a fully wireless version in the future. This type of robot could facilitate the inspection of submerged environments, environmental monitoring, and operations that require compact machines capable of performing highly precise maneuvers. Most interestingly, the major breakthrough in this case did not come from adding more motors or complex computers, but rather from an intelligent mechanical structure capable of achieving much more with less.
