Wed. Dec 6th, 2023
    Robotic Prosthetic Ankle Enhances Stability for Amputees

    Amputees with lower limb prostheses often face challenges in maintaining balance and stability, especially when standing still. However, a recent breakthrough in robotic technology by researchers at North Carolina State University has the potential to address this issue. They have developed a robotic prosthetic ankle that utilizes electromyographic (EMG) sensors to monitor muscle activity in the residual limb, allowing for adjustments to be made in real-time to maintain balance.

    The complexity of “postural control,” the ability to make unconscious movements to stay stable, has been a significant hurdle in prosthetic devices. The robotic ankle aims to bridge this gap by mimicking the natural adjustments made by our muscles when standing still. By interpreting the electrical signals sent through the residual muscle in the lower limb when the participant thinks about moving the amputated limb, the sensors translate these signals into commands for the prosthetic device.

    To test the effectiveness of the robotic ankle, five volunteers with below-knee amputations participated in the study. The researchers conducted perturbations to challenge the participants’ balance and observed how the robotic ankle assisted them in maintaining stability. Remarkably, the technology allowed the participants to shift their postural control strategy and return to their instinctive response for stability. This finding is crucial because individuals with intact lower limbs rely on ankle control for postural stability.

    The study, published in the journal Science Robotics, highlights the potential of neural prosthesis control in restoring near-normative neuromechanics for standing postural control. By leveraging the power of EMG signals and robotic technology, researchers are paving the way for enhanced stability and mobility for lower limb amputees.


    1. How does the robotic prosthetic ankle work?

    The robotic prosthetic ankle uses electromyographic (EMG) sensors placed on the residual limb muscles to monitor muscle activity. It translates the electrical signals produced when the individual thinks about moving the amputated limb into commands for the prosthetic device, enabling real-time adjustments to maintain balance.

    2. How does this technology address the challenges faced by amputees in maintaining stability?

    The technology mimics the unconscious adjustments made by muscles in our legs when standing still, providing a solution to the complexity of postural control. By allowing users to return to their instinctive response for stability, the robotic ankle assists amputees in overcoming the difficulties associated with prosthetic devices.

    3. What did the study reveal about the effectiveness of the robotic ankle?

    The study demonstrated that the robotic ankle, controlled by EMG signals, enables users to achieve natural stability. During perturbations that challenged participants’ balance, the technology allowed them to change their postural control strategy and maintain stability, resembling the response of individuals with intact lower limbs.

    Sources: Science Robotics, North Carolina State University