Computational modelling of an automatic wheelchair lift system for assistive technology

Assistive technologies promote greater independence by enabling people with disabilities to perform tasks that usually would be more difficult to achieve. The Laboratory of Bioengineering and Biomaterials of the Federal Institute of Technology in Sao Paulo is developing new assistive technologies with the purpose of contributing, providing and expanding the functional abilities of the physically disabled promoting social inclusion. The regular wheelchair faces obstacles along its route and restrictions of mobility in environments without accessibility. One of these restrictions is related to reach objects above the wheelchair height. A computational modelling of an automatic wheelchair lift system was developed to design and simulate a wheelchair that allows the user to access objects and interact with other people in the same height. The three-dimensional CAD model was the basis for static and dynamic computational analysis. In order to validate it, a conventional wheelchair was adapted with the implementation of a vertical automatic elevation system in its seat. As results, the design methodology adopted followed by the computational analyses were proved its consistency. A predicted deviation of 5 mm from the center of the seat was measured in the assembled prototype. The control system was also improved by the determination of safety parameters, minimum and maximum height and inclination angle. Comparing the results, it was concluded that the simulations were validated with the prototype measurements. The wheelchair lift system was considered an assistive technology affordable to all social classes.