Real-time force control of an SEA-based body weight support unit with the 2-DOF control structure

TL;DR

This paper presents a novel gravity offloading BWS system with a series elastic actuator and a 2-DOF control approach, validated through simulations and experiments, enhancing real-time force control for rehabilitation.

Contribution

Introduces a new gravity offloading BWS system with series elastic actuation and a 2-DOF control scheme for improved force control performance.

Findings

Validated the BWS system through simulation and experiments.

Achieved accurate and robust force control in real-time.

Enhanced human-robot interaction in rehabilitation settings.

Abstract

Body weight support (BWS) is a fundamental technique in rehabilitation. Along with the dramatic progressing of rehabilitation science and engineering, BWS is quickly evolving with new initiatives and has attracted deep research effort in recent years. We have built up a novel gravity offloading system, in which the patient is allowed to move freely in the three-dimensional Cartesian space and receives support against gravity. Thus, the patients, especially for those that suffer from neurological injury such as stroke or spinal cord injury, can focus their residual motor control capabilities on essential therapeutic trainings of balance and gait. The real-time force control performance is critical for the BWS unit to provide suitable support and avoid disturbance. In this work, we have re-designed our BWS unit with a series elastic actuation structure to improve the human-robot interaction performance. Further, the 2 degrees of freedom (2-DOF) control approach was taken for accurate and robust BWS force control. Both simulation and experimental results have validated the efficacy of the BWS design and real-time control methods.