Robotic Lower Limb Exoskeletons Using Proportional Myoelectric Control

Conf Proc IEEE Eng Med Biol Soc, 2009 · DOI: 10.1109/IEMBS.2009.5333984 · Published: January 1, 2009

Assistive Technology Rehabilitation Biomechanics

Simple Explanation

Robotic lower limb exoskeletons are being developed to help people move better, especially those with disabilities or injuries. These exoskeletons can increase a person's strength or help them relearn how to move correctly. The University of Michigan Human Neuromechanics Laboratory is building exoskeletons to understand how humans move and to help people recover from neurological injuries. Their exoskeletons use proportional myoelectric control, which means the exoskeleton's power is controlled by the wearer's own muscle signals. This type of control allows the exoskeleton to amplify the wearer's movements in a natural way, which can help them adapt and improve their muscle coordination. Proportional myoelectric control may offer advantages over other control methods for exoskeletons used in research and rehabilitation.

Study Duration

Not specified

Participants

Healthy human subjects and individuals with incomplete spinal cord injury

Evidence Level

Not specified

Key Findings

1
Healthy humans can quickly adjust to walking with robotic ankle exoskeletons, ultimately using less energy.
2
Individuals with incomplete spinal cord injuries show rapid changes in muscle activation patterns when practicing walking with ankle exoskeletons.
3
The type of controller used in a robotic lower limb exoskeleton can significantly affect physical performance, regardless of the hardware.

Research Summary

The study focuses on the development and application of robotic lower limb exoskeletons, particularly those controlled by proportional myoelectric control. This control method uses the wearer's muscle signals to control the exoskeleton's movements, offering a physiological approach to augmenting or restoring mobility. Experiments with healthy individuals and those with spinal cord injuries demonstrate that users can quickly adapt to these exoskeletons, modifying their muscle activation patterns and improving their gait. The adaptation depends on the mechanics of the exoskeleton and the biological control signal. The research suggests that proportional myoelectric control can be a valuable tool for both studying human locomotion and rehabilitating individuals with neurological impairments. It allows for a more direct and intuitive interaction between the user and the exoskeleton, potentially leading to better outcomes.

Practical Implications

Enhanced Rehabilitation Strategies

Proportional myoelectric control in exoskeletons can be used to develop more effective rehabilitation programs for individuals with neurological disorders by amplifying the relationship between muscle activation and proprioceptive feedback.

Improved Exoskeleton Design

Understanding the adaptation mechanisms to robotic assistance can inform the design of more intuitive and effective exoskeletons, optimizing their mechanical properties and control strategies.

Personalized Assistive Devices

Myoelectric control allows for personalized assistive devices that respond to the individual's specific needs and abilities, providing customized support and promoting active participation in movement.

Study Limitations

1
The artificial pneumatic muscles are highly underdamped which makes them poor choices for position control tasks.
2
The force-velocity relationship of the artificial pneumatic muscles is different from human muscle.
3
Hand held controls required higher level cognition.

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