Exploring and testing of orthopedic exoskeletons

Abstract

Exoskeletons are a growing technology in both industry and healthcare. With the increasing number of cases of musculoskeletal disorders, exoskeletons can be a potential solution for the rehabilitation of people with such disorders.

The department of electrical engineering at Chalmers University of Technology, working with Sahlgrenska University Hospital, wants to develop the understanding and technology of exoskeletons. A previous student group of Chalmers developed an elbow exoskeleton for this task, which used the pre-contracted exoskeleton EduExo lite 2 from AUXIVO.

The goal of this project is to improve the movement of the previous student group’s elbow exoskeleton, as its movement system was too unnatural and static. This was done by improving and developing a more dynamic movement system for the elbow exoskeleton, to further develop understanding and research of orthopedic exoskeletons for rehabilitation, without introducing new hardware components or replacing the existing hardware components provided by the group.

Developing the movement system required first testing the learning the response time between the microcontroller and feedback servomotor, as well as the rotation speed and resolution of the feedback servomotor. Spline and polynomial functions were used to better simulate the natural movement of a human arm, as it gives motion a gradual increase and decrease in movement velocity.

The resulting code made it a dynamic movement control system, where movement from any start and end point, results in a smoother and softer motion, where the duration of the movement can also be altered.

The result of this project provides good grounds for potential further development, which can lead to a dynamic modular movement system to provide ways easily adapted to a patient’s specific needs.