Updated: Jun 29
Researchers from the Department of Mechanical Science and Bioengineering at Osaka University invented a new kind of walking robot that takes advantage of dynamic instability to navigate. By changing the flexibility of the couplings, the robot can be made to turn without the need for complex computer control systems. This work may assist in the creation of rescue robots that are able to traverse uneven terrain.
In Shona 'Chongololo' is often used to describe a millipede or centipede.
Most animals on Earth have evolved a robust locomotion system using legs that provides them with a high degree of mobility over a wide range of environments. Somewhat disappointingly, engineers who have attempted to replicate this approach have often found that legged robots are surprisingly fragile.
The breakdown of even one leg due to repeated stress can severely limit the ability of these robots to function. In addition, controlling a large number of joints so the robot can transverse complex environments requires a lot of computer power. Improvements in this design would be extremely useful for building autonomous or semi-autonomous robots that could act as exploration or rescue vehicles and enter dangerous areas.
Myriapod robot (A) and Variable body-axis flexibility mechanism
(B. Front view, C. Top view, D. Schematics of top view)
Credit: 2023, Aoi et al., Soft Robotics
Now, investigators from Osaka University have developed a biomimetic “myriapod” robot that takes advantage of a natural instability that can convert straight walking into curved motion. In a study published recently in Soft Robotics, researchers from Osaka University describe 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 couplings can be modified with motors during the walking motion. The researchers showed that increasing the flexibility of the joints led to a situation called a “pitchfork bifurcation,” in which straight walking becomes unstable. Instead, the robot transitions to walking in a curved pattern, either to the right or to the left. Normally, engineers would try to avoid creating instabilities.
Stable and unstable walking patterns depending on the body-axis flexibility
Credit: 2023, Aoi et al., Soft Robotics
However, making controlled use of them can enable efficient maneuverability. “We were inspired by the ability of certain extremely agile insects that allows them to control the dynamic instability in their own motion to induce quick movement changes,” says Shinya Aoi, an author of the study. Because this approach does not directly steer the movement of the body axis but rather controls the flexibility, it can greatly reduce both the computational complexity as well as the energy requirements.
Discussion and Conclusion
Maneuverability and efficiency are critical issues for legged robots. this study focused on dynamic instability to address these issues, inspired by the agile locomotion of cockroaches. Maneuverability is related to the ability to change movement direction. When the movement direction is destabilized during locomotion, the instability provides driving forces to rapidly change the movement direction and thus improves maneuverability.
In addition to cockroaches, many animals are thought to use dynamic instability to enhance maneuverability in their locomotion. In particular, because the instability is determined by the body dynamics through interaction with the environment, it is outstanding in locomotion generated through aerodynamics and hydrodynamics, such as the locomotion of flying insects and sea animals. In addition to such biological systems, some fighter aircraft, such as the F-16, are designed to be aerodynamically unstable to increase maneuverability. The use of dynamic instability is thus useful from both biological and engineering viewpoints.
Continent & Context
Is Africa ready for robotic centipedes? And is there an opportunity here to explore?
Looking at the broader scope a robotic 'chongololo' can have several potential applications in Africa, addressing various challenges and providing innovative solutions.
Here are a few examples:
Agriculture: The centipede could be used for automated crop monitoring and precision farming. Equipped with sensors and cameras, it can collect data on soil conditions, crop health, and pest infestations. This information can help farmers make informed decisions about irrigation, fertilization, and pest control, leading to increased crop yields and reduced resource wastage.
Search and Rescue: In disaster-prone regions, a robotic centipede could navigate difficult terrains, such as rubble and debris, to locate and assist survivors in search and rescue operations. Its modular design and flexible body can allow it to maneuver through tight spaces and reach inaccessible areas, providing vital aid during emergencies.
Environmental Monitoring: The centipede could serve as an environmental monitoring tool, gathering data on deforestation, wildlife populations, and habitat conditions. By traversing through forests, it can collect information on flora and fauna, helping conservationists and researchers assess the impact of human activities on ecosystems and develop appropriate conservation strategies.
Healthcare Support: In remote or underserved areas, the centipede could act as a mobile healthcare assistant. It could transport medical supplies, deliver medications, or even provide basic diagnostic services. The robot's ability to navigate challenging terrain can help overcome infrastructure limitations and improve access to healthcare services.
Infrastructure Inspection: The centipede's flexibility and adaptability make it well-suited for inspecting infrastructure such as pipelines, power lines, or bridges. It can traverse complex structures, identifying defects, leakages, or areas in need of repair. Regular inspections conducted by robotic centipedes can enhance the safety and reliability of critical infrastructure.
These are just a few examples of the potential applications for a robotic centipede in Africa. The specific use cases may vary based on regional needs, technological advancements, and the local context.