Real-time force control of an SEA-based body weight support unit with the 2-DOF control structure
This work addresses the need for accurate and robust force control in rehabilitation devices for patients with neurological injuries, though it appears incremental as it builds on existing BWS technology with specific enhancements.
The authors tackled the problem of improving real-time force control for a body weight support (BWS) unit used in rehabilitation by redesigning it with a series elastic actuation structure and implementing a 2-DOF control approach, with simulation and experimental results validating the efficacy of the design and methods.
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.