Multi-Modal Human-Machine Control Interfaces of Upper Limb Motorized Exoskeletons for Severely Impaired Patients

Abstract

The aim of this study concerns the evaluation and comparison of different Human-Machine Interfaces for the control of an upper limb motorized exoskeleton for severely impaired patients. Different approaches (i.e. manual, vocal, visual control) are tested in a simulation environment on three subjects affected by muscular dystrophy with the aim of assessing the capability of the system to interact with the user and vice versa. A Graphical User Interface shows the simulated behavior of the exoskeleton to the user which has to perform reaching tasks in the space by moving the exoskeleton end-effector to defined virtual targets that are displayed on the screen. Specific assessment of the interaction of the user with each control interface is achieved, while a quantitative evaluation of the usability of all the three approaches is provided by a System Usability Scale (SUS) questionnaire. All patients were able to interact with all control interfaces without difficulties and to complete reaching tasks in simulation. SUS scores showed overall good usability of the Human-Machine Control Interfaces suggesting that the manual and the vocal control interfaces are preferred by the subjects.