Researchers from the Department of Mechanical Science and Bioengineering at Osaka University have created a new type of mobile robot that takes advantage of dynamic instability for locomotion. By changing the flexibility of the couplings, the robot can be made to rotate without the need for complex computer control systems. This work could help create rescue bots that can traverse rough terrain.
Most animals on Earth have evolved a robust locomotion system using legs that provide them with a high degree of mobility in a wide variety of environments. Somewhat disappointingly, engineers who attempted to replicate this approach often found that legged robots were surprisingly fragile. Failure of one leg due to repetitive stress can severely limit these robots’ ability to function. Furthermore, controlling a large number of joints in order for a robot to traverse complex environments requires a great deal of computing power. Improvements to this design could be very useful for building autonomous or semi-autonomous robots that can serve as exploration or rescue vehicles and for entering hazardous areas.
Now, researchers at Osaka University have developed a biomimetic “myriapod” robot that takes advantage of natural instability that can transform upright walking into a curvilinear motion. In a study recently published in soft robots, Researchers from Osaka University describe their robot, which has six parts (with two legs attached to each part) and flexible joints. With an adjustable screw, the elasticity of the couplings can be changed using motors during the walking motion. Researchers have shown that increased joint flexibility leads to a condition called “bifurcation of the fork,” in which upright walking becomes unstable. Instead, the robot shifts to walking in a curvilinear pattern, either to the right or to the left. Usually, engineers try to avoid creating instability. However, their controlled use can allow for effective maneuvering. “The ability of some highly flexible insects to control the dynamic instability of their movement to trigger rapid changes in locomotion inspired us,” explains Shinya Aoi, author of the study. Since this approach does not directly direct body axis motion, but rather controls flexibility, it can significantly reduce computational complexity as well as energy requirements.
The team tested the robot’s ability to reach specific locations and found that it could navigate curved paths to targets. “We can expect applications in a variety of scenarios, such as search and rescue, working in hazardous environments, or exploring other planets,” says Mao Adachi, another study author. Future releases may include additional chips and control mechanisms.
