Head movement and facial expression-based human-machine interface for controlling an intelligent wheelchair

This paper presents a human machine interface (HMI) for hands-free control of an electric powered wheelchair (EPW) based on head movements and facial expressions detected by using the gyroscope and 'cognitiv suite' of an Emotiv EPOC device, respectively. The proposed HMI provides two control modes: 1) control mode 1 uses four head movements to display in its graphical user interface the control commands that the user wants to execute and one facial expression to confirm its execution; 2) control mode 2 employs two facial expressions for turning and forward motion, and one head movement for stopping the wheelchair. Therefore, both control modes offer hands-free control of the wheelchair. Two subjects have used the two control modes to operate a wheelchair in an indoor environment. Five facial expressions have been tested in order to determine if the users can employ different facial expressions for executing the commands. The experimental results show that the proposed HMI is reliable for operating the wheelchair safely.