Robotics in Rehabilitation - Part I: Requirements and Control Issues

Robotics in rehabilitation present many aspects in the domain of physical human-robot interaction. The design and the application of robots in neuro-motor recovery of impaired people pose, in fact, demanding requirements in terms of robot control, safety, dependability and openness to sensor interfaces for the provided solutions. Conditions and modalities of the use of robots in rehabilitation is still debated because of the relatively recent availability of suitable machines and, mostly, because of the manifest difficultie in setting clinical trials for experimentations and validations. Nevertheless, the rehabilitation community comes to a general agreement about the effica y of natural movements during training sessions. As a resulting requirement, robotic systems in rehabilitation have to display properties beyond the state-of-the-art in terms of kinematic topology, available power and, more importantly, in control architectures. Such architectures, in particular, should be suitable for allowing the implementation of the most advanced interaction control strategies and the integration of very helpful subsystems, like sensors, motion tracking and analysis systems, virtual and augmented reality, multiple interfaces. Focusing on the rehabilitation of the upper limb, the use of robotic manipulators as end-effector based assisting machines enables a wide range of investigations in the fiel of interaction control. Users (in this case patients) are therefore considered entirely part of the system from both an application (safety and dependability) and a modeling perspective. In this work, reviews of human-robot interaction requirements, control strategies and modeling are presented. Such background introduces a case study about the use of a manipulator coupled with several subsystems for the rehabilitation of the upper limb.