LOWER-LIMB WEARABLE ROBOTICS
Amputees generally have an asymmetric gait, higher metabolic consumption, and are prone to falling with a passive prosthesis. Our research is driven by designing a powered knee-ankle prosthesis and developing human-inspired control strategies for above-knee amputees to walk in a stable, able-bodied manner. The proposed work is designing a time-invariant, phase-based controller, which require no retuning of control parameters independent of the patient or task. Here are the aims of this research work.
Develop a unified controller that systematically captures both stance and swing period of human walking for a powered prosthesis.
Design and build a powered knee-ankle prosthesis validating implementation of the unified control strategy for real-time control.
Perform human experiments to demonstrate the clinical feasibility of the unified controller with multiple amputee subjects using a powered prosthesis.
A Unified Virtual Constraint Control for a Powered Knee-Ankle Prosthesis
To provide control to a multi-joint powered prosthesis, we developed a new class of virtual constraints unified over the gait cycle while respecting the continuous, periodic nature of human walking.
Feedback linearization was implemented for the prosthesis controller and validated using an amputee biped model. Each walking speed produced asymptotically stable gaits.
Design and Manufacturing of a Powered Knee-Ankle Prosthesis
The powered prosthesis contains high-torque actuators for both knee and ankle joints with on-board sensors.
The prosthesis design met the joint kinematics and kinetics requirements for amputees to ambulate as an able-bodied.
Amputee Experiments of using the Phase-Based Unified Controller