Researchers at North Carolina State University and the University of North Carolina at Chapel Hill have made significant strides in enhancing the functionality of robotic prosthetics. A newly developed algorithm personalizes these devices, optimizing not only their movement but also promoting a more natural walking pattern for users. This dual approach aims to alleviate health issues often faced by amputees, such as lower back pain and hip problems.
The findings are detailed in the paper titled “Addressing Human-Robot Symbiosis via Bilevel Optimization of Robotic Knee Prosthesis Control,” published in the journal IEEE Transactions on Robotics. According to Varun Nalam, co-lead author and assistant research professor, this algorithm represents a landmark advancement in the field. He explains that while previous algorithms primarily focused on enhancing the performance of robotic limbs, this one also considers the user’s overall physical behavior.
Health Challenges and Movement Optimization
Amputation, particularly above the knee, can lead to a host of movement-related issues, affecting how individuals use other parts of their bodies. “When people have an amputation above the knee, it affects the way they move other parts of their body,” Nalam notes. The traditional focus of robotic prosthetics has been on replicating the movement of the missing joint. However, this new algorithm seeks to ensure that the user’s body moves as naturally as possible, thereby reducing the risk of secondary health issues.
“Our goal was to develop a new algorithm that allows us to do two things,” Nalam states. “We still want to ensure that the prosthetic knee joint is functioning properly—but we also want to ensure that the user’s body is moving in the same way it would have before the amputation.” This holistic approach not only restores leg motion but also aims to prevent complications associated with altered movement.
Innovative Testing and Results
The research builds on earlier work that introduced an intelligent system capable of tuning powered prosthetic knees quickly, using reinforcement learning. Now, the new algorithm employs inverse reinforcement learning to consider both the movement of the prosthetic knee and the user’s hip, offering a more integrated solution to gait issues.
During the testing phase, researchers recruited five participants, two of whom had undergone an above-the-knee amputation. All participants completed various tasks using a robotic prosthetic knee under two different conditions: one using the previous tuning system and the other incorporating the new algorithm. The results were promising, showing improved hip range of motion for all subjects.
“The main finding here was that incorporating the new algorithm improved hip range of motion for all five subjects, demonstrating its potential for enhancing hip health,” Nalam explains. Additionally, the study noted alterations in gait patterns, with participants taking longer steps, suggesting a more natural walking experience.
Future Directions and Clinical Applications
Looking ahead, the research team plans to collaborate with clinicians to explore the long-term impacts of this new technology on user well-being. Helen Huang, senior author of the paper, highlights the importance of this next phase. “From a practical standpoint, next steps include working with clinicians to see how it affects user well-being over time,” she remarks.
Moreover, the researchers are eager to partner with companies that manufacture robotic prosthetics to investigate how to incorporate this algorithm into existing software solutions. “From a research standpoint, we are interested in determining how this approach can be used to help address a range of human locomotive behaviors,” Nalam adds.
This innovative research marks a significant advancement in the field of prosthetics, with the potential to improve the quality of life for many individuals navigating the challenges of limb loss. As technology continues to evolve, the hope is that these breakthroughs will lead to more effective and user-friendly solutions for amputees worldwide.
