Robotic wheelchair control interface based on headrest pressure measurement.

We introduce a novel approach for proportional head control for robotic wheelchairs. An array of force sensors embedded into the headrest is used to monitor the pressure distribution changes due to the intentional head motions of the patient. The force signals are analysed and converted into fully proportional signals that control the wheelchair direction and speed. We developed a prototype interface that generates signals similar to the signals of a standard joystick control box and connected the new interface to a standard Invacare wheelchair. Tests showed that all users adapted to the control algorithm very quickly and were able to follow very precisely complex target trajectories on various speeds. The interface does not require any attachments to the user's head and does not cause any limitation of the user's field of view.