Knee Rehabilitation Device with Soft Actuation: An Approach to the Motion Control

摘要

Assistive devices in rehabilitation have gained much attention in robotics research. Recent actuation systems include compliant elements to provide advantages as natural motions and safety in the interaction with humans. These are the so-called soft actuators, among which there are series elastic actuators (SEA) and variable stiffness actuators (VSA). On the other hand, control strategies are required in order to accomplish desired tasks in a proper manner. In rehabilitation systems this is to reproduce a desired motion without affecting the patient, so the control system is crucial. In this paper, we present a control strategy for a knee rehabilitation device, with soft actuation. The goal is to control the system while maintaining the intrinsic softness of the system when the patient is in the rehabilitation process. We propose a feedback control strategy, acting in a defined threshold to maintain the stiffness of the system, combined with a feedforward decision control to reject disturbances.