A wearable biomechatronic interface for controlling robots with voluntary foot movements

This paper presents an experimental investigation on a novel interface for high level control of mechatronic systems, by exploiting voluntary user's foot movements. Based on a biomechanical analysis of the foot anatomy and joint kinematics, a sensory system is designed for detecting pressure variations on selected areas of the insole, obtained from four different foot movements that can be purposively controlled by the person. A prototype is developed that integrates four sensitive areas, battery, and electronics into a wearable insole; electronics are used for data acquisition and wireless transmission, in order to have a stand-alone device. The prototype foot interface is experimentally tested in the control of a prosthetic hand, as a model of a typical device that can be effectively operated by foot movements. Experimental trials were conducted with ten able-bodied subjects and the results confirmed the usability and effectiveness of the foot interface in terms of correct and prompt transmission of the user's intention to the controlled device. Comparative experimental trials were performed with electromyography (EMG)-based control of the same prosthesis, which represents the most advanced interface currently available in clinical implants for amputees. The comparative results showed a significant decrease in required adaptation and learning from the user's side.