Alternative Wheelchair Control Involving Intentional Muscle Contractions

This paper deals with various ways of controlling an electrically powered wheelchair beyond the usual method involving a manual joystick. The main focus is on the newest version of HaWCoS - the "HAnds-free Wheelchair COntrol System" - allowing persons with severe disabilities to reliably navigate a power wheelchair without the need to use the hands. All the user has to do is to produce a sequence of tiny contractions of an arbitrary muscle, e. g., by raising the eyebrow. The working prototype of the system, which has been realized as a stand-alone device, is introduced in detail, together with a closer look at the muscle-based control principle and a brief description of a PC-based simulator. The advantages and the drawbacks of the system are discussed on the basis of a rather simple real-life experiment. The paper also elaborates on possible approaches to improve HaWCoS (by reducing or eliminating its problems) in the future. In addition to a quick software solution and a controller implementation involving supplemental sensory information, planned "improvements" include the development of an "intelligent wheelchair" with HaWCoS being some sort of a prototype for the User Interface component.