Hybrid FES-robot cooperative control of ambulatory gait rehabilitation exoskeleton

Journal of NeuroEngineering and Rehabilitation, 2014 · DOI: 10.1186/1743-0003-11-27 · Published: March 4, 2014

Spinal Cord Injury Assistive Technology Neurology

Simple Explanation

This article presents a cooperative control strategy for a hybrid exoskeleton, designed to overcome the main disadvantages of muscular stimulation: electromechanical delay and change in muscle performance over time, and to balance muscular and robotic actuation during walking. The Kinesis system is designed to compensate gait in patients with low level of SCI and has been presented elsewhere. This type of lesion is characterized by paralysis of muscles driving the knee and ankle joints, while hip flexors (psoas) are preserved. The cooperative behavior of Kinesis allows to obtain adequate and personalized stimulation patterns, estimating muscle fatigue and reducing robotic assistance during overground assisted gait. This approach intends to give priority to the use of artificially stimulated muscles to generate leg movements.

Study Duration

Not specified

Participants

4 healthy volunteers

Evidence Level

Not specified

Key Findings

1
The hybrid FES-robot cooperative control effectively balances power contribution between exoskeleton and muscle stimulation.
2
The robotic exoskeleton decreases assistance while adequate knee kinematics are guaranteed.
3
A new technique to monitor muscle performance is employed, which allows to estimate muscle fatigue and implement muscle fatigue management strategies.

Research Summary

This article introduces a novel cooperative control strategy for a hybrid exoskeleton, designed for gait rehabilitation in individuals with spinal cord injury (SCI). The Kinesis system balances robotic and FES actuation during walking, offering opportunities for new rehabilitation interventions to induce locomotor activity in paraplegic patients. Experimental results with healthy subjects demonstrate the ability to balance power contribution between the exoskeleton and muscle stimulation, utilizing a new technique to monitor muscle performance and manage fatigue.

Practical Implications

Personalized Rehabilitation

The system allows for personalized stimulation patterns, adapting to individual patient needs.

Muscle Fatigue Management

The technique offers a strategy to monitor muscle performance and manage fatigue, potentially increasing treatment time.

Balance of Assistance

The exoskeleton can balance robotic and neuroprosthetic power sources, optimizing rehabilitation interventions.

Study Limitations

1
Imposing both a kinematic and a time defined pattern on the patient is one of the limitations of Kinesis exoskeleton control.
2
Further developments would include a more adaptable kinematic pattern to increase the cooperation between Kinesis and the residual abilities of the user.
3
Surface electrical stimulation, although closed-loop modulated, is still not achieving a physiological activation pattern.

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