Electrohydraulic musculoskeletal robotic leg
An electrohydraulic musculoskeletal robotic leg for agile, adaptive, yet energy-efficient locomotion.
Robotic locomotion on unstructured terrains requires an architecture that is both agile and adaptive. Current legged robots rely heavily on rigid electromagnetic motors and complex sensorized control systems to adapt to uneven surfaces. These systems, however, struggle to replicate the fluidity and efficiency seen in animal locomotion. To address this challenge, we have introduced a bio-inspired musculoskeletal leg driven by pairs of antagonistic electrohydraulic artificial muscles, allowing it to perform high-energy motions like jumping and fast movements while automatically adapting to obstacles and different terrains.
Key Features
- Artificial Muscles for Movement: The leg is powered by pairs of electrohydraulic muscles, which function similarly to human and animal muscles. These muscles are made from liquid-filled plastic actuators (Peano-HASELs) that contract and relax when electrically charged. This setup allows the leg to move in both directions, mimicking the flexibility of biological limbs.
- Energy Efficiency: Compared to traditional motor-driven legs, our robotic leg consumes significantly less energy. It holds positions with minimal energy loss, avoiding the heat buildup seen in conventional motors. In testing, it was shown to consume only 1.2% of the energy required by a conventional electromagnetic leg under similar conditions, making it highly efficient.
- Adaptive Movement: The leg can automatically adapt to uneven terrains, jumping over obstacles and landing smoothly. It demonstrated adaptability across grass, sand, gravel, and rocks, without the need for complex sensor feedback systems.
At the Soft Robotics Lab at ETH Zurich together with our collaborators from the Robotic Materials Department at the Max Planck Institute for Intelligent Systems, we have developed a groundbreaking robotic leg that operates using electrohydraulic artificial muscles, offering unmatched agility, adaptability, and energy efficiency. This innovative leg architecture, published in Nature Communications, represents a significant step toward the next generation of mobile robots designed to perform effectively in unstructured environments.
Groundbreaking Capabilities
- High Jumps and Fast Movements: The robotic leg can perform powerful and agile movements at frequencies beyond 5 Hz and jump up to 40% of its leg height. These characteristics make it a prime candidate for applications requiring rapid and dynamic motion, such as rescue operations.
- Self-Sensing: A unique feature of this system is its capacitive self-sensing ability, which allows the robotic leg to detect obstacles and adjust its movement without relying on external sensors. This internal proprioception is a critical advancement in soft robotics, reducing the need for heavy, complex sensing equipment.
Applications and Future Potential
This research lays the groundwork for future robots designed to navigate complex, unstructured environments, such as forests, disaster zones, or urban areas. Our current model, mounted on a boom arm for testing, is a crucial stepping stone toward developing fully autonomous, untethered walking robots powered by artificial muscles. Our ongoing research aims to integrate this leg into a complete quadrupedal or bipedal system, enhancing its capabilities for real-world deployment. Furthermore, the inherent energy efficiency and adaptability of this system open possibilities for creating robots that are not only agile but also sustainable in terms of power consumption.
The work was featured in an ETH Zurich news article titled "Artificial muscles propel a robotic leg to walk and jump".
