Adaptive control of powered transfemoral prostheses based on adaptive dynamic programming

Area of Science:

• Biomedical Engineering
• Robotics
• Rehabilitation Technology

Background:

• Powered transfemoral prostheses aim to restore natural gait.
• Current control systems often lack personalization for individual user needs.
• Adaptive control strategies are needed to optimize prosthesis performance.

Purpose of the Study:

• To develop and test a novel adaptive controller for powered transfemoral prostheses.
• To integrate Adaptive Dynamic Programming (ADP) with Finite State Impedance Control (FS-IC).
• To personalize prosthesis control for individual user objectives during walking.

Main Methods:

• Implemented Adaptive Dynamic Programming (ADP) within a prototypic active-transfemoral prosthesis (ATP).
• The ADP controller learned user performance properties through online adaptation during walking.
• Tested on an able-bodied subject to tune FS-IC impedance parameters for normative knee kinematics.

Main Results:

• The ADP controller successfully adjusted prosthesis control to achieve desired normative knee kinematics within 10 minutes.
• FS-IC impedance parameters converged while maintaining optimal human-prosthesis performance.
• Demonstrated the feasibility of ADP for adaptive control in lower limb prosthetics.

Conclusions:

• Adaptive Dynamic Programming shows promise for personalizing powered transfemoral prosthesis control.
• The developed system can adapt to user dynamics to achieve specific gait objectives.
• Future work will focus on validating the system with amputee users using user-centered objective functions.