Many animals, from micro-meter-scale bacteria to meter-scale vertebrates, rely on undulating motion to propel themselves on land and water. While undulating motion can be used for both crawling and swimming, it requires the coordination of multiple joints, so only some robots have the ability to mimic this motion.
Now, engineers at Ben-Gurion University (BGU) of the Negev in Beersheba have developed a new bio-inspired amphibious bot that utilizes a relatively simple mechanism to undulate at a good clip.
The AmphiSAW is one of the fastest and most efficient amphibious robots whose movement in water is inspired by the movement of flippers, and its land movements are inspired by centipedes.
The AmphiSAW is a reliable, simple to design, lightweight, and low-cost amphibious robot. The current version of the robot has a total length of 51.3 cm at a width of 16.4 cm and weighs 1245 grams with its batteries and control boards.
Its body is mostly 3D printed. The waterproof motor housing holds three motors (one for rotating the helix and two for rotating the legs or wheels), a controller with a global positioning system (GPS) receiver, and batteries. The robot is fitted with a wave propulsion mechanism, which generates a traveling sine wave using a single motor.
Whether on land or in the water, the amphibious robot moves quite quickly. Its bio-inspired mechanism is bio-friendly as it allows the robot to swim among fish without intimidating them. On land, the robot crawled at a speed of 1.5 body lengths per second (B/s) and swam across the surface of the water at 0.74 B/s. It can be fitted with legs or wheels at the front, which can further increase its performance, especially when crawling on uneven terrains.
“The single motor and bioinspired design contribute significantly to the robot’s efficiency, and the relative simplicity of its design means it is scalable to any size,” explains Dr. David Zarrouk, an engineer at the Ben-Gurion University of the Negev. The goal is to produce robots that can complete complex maneuvers yet use very little power to run and are straightforward to produce.
In addition to its high speeds, the robot has the lowest cost of transport among all amphibious robots reported in the literature, the researchers say.
The AmphiSAW robot has potential applications in search and rescue, especially during natural disasters such as floods and tsunamis. It can also be used in marine agriculture and fish feeding as the robot attracts fish instead of repelling them.
- Omer Guetta, Dan Shachaf, Rotem Katz, and David Zarrouk. A novel wave-like crawling robot has excellent swimming capabilities. Bioinspiration & Biomimetics, 2023; DOI: 10.1088/1748-3190/acb1e8