Intrinsic Sensing and Evolving Internal Model Control of Compact Elastic Module for a Lower Extremity Exoskeleton

Area of Science:

• Robotics
• Biomechatronics
• Control Systems

Background:

• Functional autonomous exoskeletons require precise control, low impedance, and mechanical compactness for strength and endurance enhancement.
• Previous designs utilized two elastic modules for sensing and compliant control.
• A single compact elastic module is explored to integrate sensing and control functions.

Purpose of the Study:

• To develop a control strategy for a single compact elastic module in an autonomous exoskeleton.
• To achieve precise control, back drivability, and low output impedance using the integrated module.
• To enhance human-robot interaction and exoskeleton performance.

Main Methods:

• An evolving internal model control strategy was proposed.
• The control input is derived from the deflection of the compact elastic module.
• Human-robot interaction is modeled as a disturbance approximated by output error.

Main Results:

• Experiments with the robotic exoskeleton system demonstrated satisfying performance.
• The integrated compact elastic module effectively achieved both sensing and control objectives.
• The proposed control scheme showed promising application feasibility.

Conclusions:

• A single compact elastic module integrated with evolving internal model control is effective for autonomous exoskeletons.
• This approach enhances control precision and human-robot interaction.
• The system demonstrates feasibility for strength augmentation and endurance enhancement applications.