Force sensing control for electric powered wheelchairs

People with many types of disabilities use electric powered wheelchairs (EPWs) for mobility. Excessive intention tremor, limited range of motion, athetoid motions, and spastic rigidity can reduce or prohibit the control over an EPW. This study focused on the design and testing of a newly developed isometric joystick (IJ) for EPW control. The IJ was tested against existing performance standards and compared to a commercial position sensing joystick (PSJ). When averaged across all subjects (both controls and impaired subjects) the root-mean-square tracking error and time to complete the driving course were not significantly different when using the rule (p<0.05). Results within a subject, however, did show significance. Across all subjects, nevertheless, the IJ was superior to the PSJ for two tasks: driving straight and driving in a circle. Further development of control algorithms, especially the implementation of digital control, could lead to greater improvement in performance with the IJ.