Extrusion-Based 3D Bioprinting of Bioactive and Piezoelectric Scaffolds as Potential Therapy for Treating Critical Soft Tissue Wounds.

This study focuses on developing bioactive piezoelectric scaffolds that could deliver bioelectrical cues to potentially treat injuries to soft tissues such as skeletal muscles and promote active regeneration. To address the underexplored aspect of bioelectrical cues in skeletal muscle tissue engineering (SMTE), we developed piezoelectric bioink based on natural bioactive materials such as sodium alginate, gelatin, and chitosan. Extrusion-based 3D bioprinting was utilized to develop scaffolds that mimic muscle stiffness and generate electrical stimulation (E-stim) when subjected to forces.

Early evaluation of a powered transfemoral prosthesis with force-modulated impedance control and energy regeneration.

Individuals with an above-knee (AK) amputation typically use passive prostheses, whether reactive (microprocessor) or purely mechanical. Though sufficient for walking, these solutions lack the positive power generation observed in able-bodied individuals. Active (powered) prostheses can provide positive power but suffer complex control and limited energy storage capacities.

Targeted muscle effort distribution with exercise robots: Trajectory and resistance effects.

The objective of this work is to relate muscle effort distributions to the trajectory and resistance settings of a robotic exercise and rehabilitation machine. Muscular effort distribution, representing the participation of each muscle in the training activity, was measured with electromyography sensors (EMG) and defined as the individual activation divided by the total muscle group activation. A four degrees-of-freedom robot and its impedance control system are used to create advanced exercise protocols whereby the user is asked to follow a path against the machine's neutral path and resistance.

Real-time optimization of an ellipsoidal trajectory orientation using muscle effort with Extremum Seeking Control.

We present an approach for real-time model-free optimization of the orientation of the elliptical trajectory. The performance is evaluated in simulation and experimental stages. Our model-free approach is based on the use of Extremum Seeking Control (ESC) as the real-time optimizer.

Optimal design and control of an electromechanical transfemoral prosthesis with energy regeneration.

In this paper, we present the design of an electromechanical above-knee active prosthesis with energy storage and regeneration. The system consists of geared knee and ankle motors, parallel springs for each motor, an ultracapacitor, and controllable four-quadrant power converters. The goal is to maximize the performance of the system by finding optimal controls and design parameters.

Optimal Mixed Tracking/Impedance Control With Application to Transfemoral Prostheses With Energy Regeneration.

Objective: We design an optimal passivity-based tracking/impedance control system for a robotic manipulator with energy regenerative electronics, where the manipulator has both actively and semi-actively controlled joints. The semi-active joints are driven by a regenerative actuator that includes an energy-storing element.

Method: External forces can have a large influence on energy regeneration characteristics.