Sistema de asistencia a la propulsión para sillas de ruedas convencionales
López Isaza, Sergio | 2019
Wheelchairs are assistive technologies; they allow those who use them to access and enjoy their rights as human beings. Its users vary in age, occupation, activity level, health condition, socio-economic status, and other characteristics. Therefore, today there is a wide variety of these devices seeking to meet the different needs, preferences and limitations of those interested.
For instance, electric wheelchairs are preferred by users with greater motor limitations due to their easy control, but they have disadvantages such as their size, weight and price. Manual wheelchairs are more compact, easy to repair, resistant, cheap, and promote physical activity. However, they need to be propelled by the user at all times, which can lead to pathologies of the joints involved, causing additional limitations and secondary disabilities.
Therefore, a propulsion assistance system for manual wheelchairs is proposed, with the objective of supporting its movement when the user finds it necessary, especially in difficult terrains. Thus, the joint wear caused by the prolonged use of these mobility systems could potentially be reduced, while maintaining many of their advantages.
First, a mechanical system was designed using the product design methodology of Ulrich and Eppinger, based on a series of needs and requirements discovered through interviews and reviews of related available products. Then, a speed control system was proposed to guide the movement of the electromechanical section. A PI controller was designed using Labview and, MuPAD and System Identification tools from MATLAB®.
Finally, the behavior of the mechanical system was analyzed by finite element analysis, to ensure a stable and resistant structure. The controller’s response and performance were also evaluated in order to verify its design.
The preliminary design of a propulsion assistance system was then proposed, a product that could improve the mobility, prevent injuries and promote the labor, social and cultural participation of manual wheelchair users. Future approaches to this work could be done with a view to translating it into a real product, analyzing its performance with a physical prototype and making the necessary adjustments.