Position Based Impedance Control Strategy for a Lower Limb Rehabilitation Robot

Area of Science:

• Robotics
• Rehabilitation Engineering
• Biomechanics

Background:

• Active rehabilitation training enhances neural engagement and recovery outcomes.
• Accurate estimation of patient active torques is crucial for effective training.
• Human-robot interaction requires compliant and safe control strategies.

Purpose of the Study:

• To propose a position-based impedance control strategy for active rehabilitation training.
• To develop an accurate human-robot dynamic model for torque estimation.
• To ensure patient safety and comfort during robotic-assisted rehabilitation.

Main Methods:

• A novel friction model incorporating joint coupling and viscosity was designed.
• A virtual tunnel was implemented to limit motion and ensure safety.
• A double closed-loop position-based impedance control strategy was utilized.

Main Results:

• The proposed dynamic model accurately estimated patient active torques.
• The control strategy facilitated a compliant human-robot interaction interface.
• Experimental results demonstrated comfortable, natural, and safe training completion.

Conclusions:

• The developed system enables precise active torque estimation for rehabilitation.
• The impedance control strategy ensures safe and effective human-robot interaction.
• This approach improves the overall quality and outcomes of active rehabilitation training.