Centipede robot walking around

Osaka, Japan – Researchers from the Department of Mechanical Science and Bioengineering at Osaka University have invented a new kind of walking robot that takes advantage of dynamic instability to navigate. By changing the flexibility of the clutch, the robot can be made to rotate without the need for complex computational control systems. This work can help create a rescue robot capable of traversing uneven terrain.

Most of the animals on Earth have developed a powerful locomotion system using their legs which gives them a high degree of mobility in a variety of environments. Somewhat disappointingly, engineers trying to replicate this approach have often found legged robots to be extremely fragile. Breaking even one leg from repeated stress can severely limit the robot’s ability to function. In addition, controlling a large number of connections for a robot to traverse complex environments requires a lot of computer power. These improvements in design will be especially useful for building autonomous or semi-autonomous robots that can act as exploration or rescue vehicles and enter hazardous areas.

Now, researchers from Osaka University have developed a biomimetic “myriapod” robot that takes advantage of natural instability to turn straight walking into curved movements. In a study published recently in Soft Robotics, researchers from Osaka University described their robot, which consists of six segments (with two legs connected to each segment) and flexible joints. Using an adjustable screw, the flexibility of the clutch can be modified with the motor during the running movement. The researchers demonstrated that increased joint flexibility leads to a situation called “pitch fork branching,” in which walking straight becomes unsteady. Instead, the robot transitions to walk in a curved pattern, either to the right or to the left. Usually, engineers will try to avoid creating instability. However, utilizing them in a controlled manner allows for efficient maneuverability. “We were inspired by the ability of certain insects to be very agile which allows them to control dynamic instability in their own movements to induce rapid movement changes,” said Shinya Aoi, author of the study. Because this approach does not directly direct the movement of the body axes, but instead controls flexibility, it can greatly reduce computational complexity as well as energy requirements.

The team tested the robot’s ability to reach specific locations and found that the robot could navigate by taking a curved path toward a target. “We can foresee applications in various scenarios, such as search and rescue, working in hazardous environments or exploration on other planets,” said Mau Adachi, another author of the study. Future versions may include additional segments and control mechanisms.

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The article, “Maneuverable and efficient propulsion of a myriapod robot with variable body axis flexibility through instability and branching,” was published in Soft Robotics at DOI: https://doi.org/10.1089/soro.2022.0177