Researchers at Osaka University’s Department of Mechanical Science and Bioengineering have created an innovative walking robot that utilizes dynamic instability for navigation. This groundbreaking design eliminates the need for complex computational control systems by enabling the robot to turn simply by adjusting the flexibility of its couplings. This development holds promise for the creation of rescue robots capable of traversing uneven terrain.
While most animals have evolved robust leg-based locomotion systems that provide them with remarkable mobility across diverse environments, engineers have struggled to replicate this approach with legged robots. These robots often prove to be unexpectedly fragile, as the repeated stress on their legs can lead to breakdowns that severely limit their functionality.
Furthermore, controlling a large number of joints in order for a robot to navigate complex environments requires substantial computational power. Enhancements in this design would be immensely valuable for the construction of autonomous or semi-autonomous robots that could serve as exploration or rescue vehicles, capable of safely accessing hazardous areas.
The researchers from Osaka University have now devised a biomimetic “myriapod” robot that exploits a natural instability, enabling it to convert straight walking into curved motion. In their study recently published in Soft Robotics, the scientists describe the robot, which comprises six segments, each equipped with two legs and flexible joints. By utilizing adjustable screws and motorized mechanisms, the flexibility of the couplings can be modified during the walking motion.
The researchers discovered that by increasing the flexibility of the joints, they could induce a “pitchfork bifurcation” situation, where the robot’s straight walking became unstable. Surprisingly, this instability proved to be advantageous as the robot smoothly transitioned into a curved walking pattern, either to the right or left. While engineers typically aim to avoid instabilities, the researchers recognized the potential of harnessing them for efficient maneuverability.
Shinya Aoi, one of the study’s authors, explains, “We drew inspiration from highly agile insects that can skillfully control dynamic instability to achieve rapid changes in movement.” By focusing on controlling flexibility rather than directly steering the body axis, this approach significantly reduces both the computational complexity and energy requirements involved.
To evaluate the robot’s capabilities, the team conducted tests to assess its ability to reach specific locations. They observed that the robot successfully navigated by following curved paths towards the desired targets. Mau Adachi, another author of the study, envisions numerous potential applications, including search and rescue missions, hazardous environment operations, and exploration missions on other planets. The researchers also anticipate future iterations of the robot to incorporate additional segments and control mechanisms.
Source: Osaka University