Comparative empirical usability assessment of two HRI input devices for a mobile robot

It is now possible to control an Unmanned Ground Vehicle (UGV) with a free smartphone app such as ROS Control. Smartphones offer such low cost and easily available human-robot interface (HRI) controlling robots with tilt gestures. However, tilt gestures are not used in the more commonly available UGV control devices, such as joystick and button based gamepads. Tilt gestures have not been studied in terms of their effectiveness for controlling UGVs. If they are effective, then the low cost and high availability of smartphones running apps such as ROS Control can make a huge change in the world of HRI and control devices for UGV for the developing world. They can be ruggedized and are low cost, and more familiar to the general populace — which are factors that can help the adoption of robotics in India. This research explores the ease of use and effectiveness in controlling a UGV by benchmarking a tilt-based HRI (on the ROS Control app) with the more established joystick and button based HRI on a gamepad. A 40-person usability study using both devices in Gazebo, a robotic simulated environment, was conducted. Performance metrics (time on task and lane deviations) were measured, to indicate effectiveness. However, the statistical analysis conducted using Wilcoxon Signed Rank test shows a significant difference in the use of both the input devices in controlling a UGV favoring the gamepad. However, most of the participants report the tilt based app as more controllable and highly usable.