Dynamic model of a stair-climbing mobility system and its experimental validation

The use of Electric-Powered Wheelchairs (EPWs) implies a dramatic improvement for people with physical disabilities, thus enabling them to lead more independent lives and to interact in society. Although numerous modifications have been made in recent years to improve access to transportation services and public buildings, the problem of a standard EPW dealing with certain architectural barriers has not yet been satisfactorily resolved. In order to contribute toward solving some of these problems, a stair-climbing mobility system (SCMS) which is capable of negotiating architectural barriers such as curbs, ramps, and staircases was developed in previous works. In this paper, is presented a novel dynamics model of a SCMS based on Newton formulation. It is characterized by the definition of a solely point mass located in the center of mass of the system and the assumption of quasistatic conditions. Additionally, taking into account that the SCMS adopt different mechanical configurations, the dynamics model incorporates relations between all the different actuators involved in each configuration of the SCMS and its generalized coordinates allowing different dynamic control strategies to be addressed. Finally, encouraging experimental results have been reported which confirm a high reliability of the model-experiment of the SCMS as it ascends a staircase.