A Shared Control Approach to Safely Limiting Patient Motion Based on Tendon Strain During Robotic-Assisted Shoulder...

Area of Science:

• Biomechanics
• Robotics
• Rehabilitation Medicine

Background:

• Musculoskeletal injuries like rotator cuff tears require careful rehabilitation to prevent re-injury.
• Robotic physiotherapy offers potential for real-time monitoring and guidance during patient recovery.

Purpose of the Study:

• To propose and evaluate a novel shared control method for robotic physiotherapy.
• To limit unsafe patient movements during rehabilitation using physical guidance based on rotator cuff strain.
• To prevent re-injury by avoiding high-strain areas in rotator cuff tendons.

Main Methods:

• A shared control method for robots was developed, utilizing a strain-space representation of the human rotator cuff.
• Two complementary predictive modules were implemented for motion correction: an impedance controller for variable damping and a trajectory planning module for temporary robot control.
• Experiments were conducted with a healthy participant to assess human-robot interaction modalities and their effect on movement and forces.

Main Results:

• The proposed method demonstrated the ability to guide patient movements away from high-strain zones in rotator cuff tendons.
• Evaluation focused on the avoidance of unsafe movements and the analysis of contact forces during rehabilitation exercises.
• Different human-robot interaction modalities were tested to understand their impact on movement safety.

Conclusions:

• The novel shared control method effectively limits unsafe movements during robotic physiotherapy for rotator cuff injuries.
• This approach enhances patient safety by preventing re-injury through intelligent physical guidance.
• The findings support the integration of biomechanical modeling and robotic systems for improved rehabilitation outcomes.