Design and control of system for elbow rehabilitation: Preliminary findings

Background. The use of an exoskeleton elbow is considered an effective treatment in several pathologies, including post-stroke complications, traumatic brain injury (TBI) and spinal cord injury (SCI), as well as in patients with neurodegenerative disorders. The effectiveness of rehabilitation is closely linked to a suitably chosen therapy. The treatment can be performed only by specialized personnel, significantly supported with the use of automated devices. Objectives. The aim of this study was to present a novel exoskeleton for elbow rehabilitation without a complicated control system. Material and methods. Single-degree-of-freedom (SDOF) solution in constructing the prototype of an elbow exoskeleton for rehabilitation purposes has been applied. The simplicity of the actuation mechanism was set as one of the priorities in the design; thus, a single-axis stepper motor with a controller was found to be adequate for providing a reliable and precise source of motion for the exoskeleton. Results. Technological development may provide novel solutions, such as an exoskeleton – a wearable, external structure which supports or (in selected applications) even replaces the muscle actuation in the patient. The reported advantages of the proposed exoskeleton reflect current state-of-the-art. The proposed control strategy relies on closed-loop position control, performance, low manufacturing cost, and predicted performance in a rehabilitation scenario. All these factors play an important role in establishing the directions for further research, e.g., an integrated force sensor in the device, measurements of torque interactions on the elbow joint, and assessment and response to an overload of articulation. Conclusions. This study suggests not only the clinical but also the possible economic and logistical advantages offered by the portability of the system, and its effective support for therapists applying an elbow exoskeleton.