Internet-based teleoperation of a mobile robot with force-reflection

In this paper, a virtual force is generated and fed back to the operator to make the teleoperation more reliable, which reflects the relationship between a slave robot and the uncertain remote environment as a form of the impedance. For the teleoperation, the teleoperated mobile robot takes pictures of the remote environment and sends the visual information back to the operator over the Internet. Because of the limitations of communication bandwidth and narrow view-angles of camera, it is not possible to watch certain regions, for examples, the shadow and curved areas. To overcome this problem, a virtual force is generated according to both the distance between the obstacle and robot and the approaching velocity of the obstacle based on the ultrasonic sensor data. This virtual force is transferred back to the master (two degrees of freedom joystick) over the Internet to enable a human operator to estimate the position of the obstacle at the remote site. By holding this master, in spite of the limited visual information, the operator can feel the spatial sense against the remote environment. It is demonstrated by experiments that this haptic reflection improves the performance of a teleoperated mobile robot significantly.