The first single actuator wave-like robot (SAW) has been developed by engineers at Ben-Gurion University of the Negev (BGU). The 3D-printed robot can move forward or backward in a wave-like motion, moving much like a worm would in a perpendicular wave. SAW can climb over obstacles or crawl through unstable terrain like sand, grass and gravel, reaching a top speed of 57 centimetres per second, five times faster than similar robots. Its minimalistic mechanical design produces an advancing sine wave with a large amplitude, using only a single motor with no internal straight spine. The breakthrough was published in Bioinspiration & Biomimetics in July. "Researchers all over the world have been trying to create a wave movement for 90 years," said Dr David Zarrouk, of BGU's department of mechanical engineering, and head of the bio-inspired and medical robotics lab. "We succeeded by finding a simple, unique solution that enables the robot to be built in different sizes for different purposes. For example, it can be scaled up for search and rescue and maintenance, or miniaturised to a diameter of one centimetre or less to travel within the human body for medical purposes, such as imaging and biopsies of the digestive system." The robot's innovative wave movement also enables it to climb through tunnels at a rate of eight centimetres per second when touching both sides. A waterproof version can swim at six centimetres per second. By adding spiny traction enhancers to each link, the team was able to propel the robot 13 per cent faster than its own wave speed. Dr Zarrouk, who has been developing robots with a minimalistic and high-performance approach for many years, claims that SAW is easy to manufacture, strong, reliable, and energy efficient, which enables long-distance travel. To find a way to replicate wave locomotion that mimics miniature biological systems, Zarrouk partnered with graduate students Ilanit Waksman, who researches swimming in viscous liquids (a movement that mimics small biological organisms) and Nir Dagani, who researches movement on flexible and slippery surfaces to model the locomotion of robots within the human body. "The robot requires barely any maintenance, which is very unusual for an almost completely 3D-printed robot prototype that's this dynamic," Zarrouk said. "I believe it will be useful for traveling through the intestine for imaging and biopsies, and for infiltrating problematic, complex security areas, such as tunnels, destroyed buildings and pipes."