Tele-autonomous obstacle avoidance allows a human operator to steer vehicles or robots remotely at high speeds and in cluttered environments, even with poor visibility or without visual contact at all (see Fig. 1.3.1). Tele-autonomous operation does also allow for safe operation of remotely controlled vehicles with significant time delays or communication disturbances.
Fig. 1.3.1: Conventional tele-operated vehicles or mobile robots rely on visual contact with the operator, either directly or through video transmissions, as shown above. Guiding such a vehicle is a formidable task, often complicated by the limited view from the TV camera. Under such conditions, a human tele-operator must exercise extreme care, especially in obstacle-cluttered environments. Consequently, the actual traveling speed of the vehicle might be very slow. When dust, smoke, or steam inhibit vision-based guidance, conventional tele-operated activity is ruled out altogether.
Fig. 1.3.2: We have developed a system that combines autonomous obstacle avoidance with tele-operation into what we call a tele-autonomous system. In this system, the tele-operator can guide the vehicle even without any visual contact. The vehicle follows the general direction prescribed by the operator; however, when the robot encounters an obstacle, it autonomously avoids collision with that obstacle, trying to match the operator's prescribed direction as closely as possible.
Information about the robot's environment is derived from its onboard sensors and is shown on the operator's screen, which closes the external control loop. The visual information enables the operator to steer the robot out of difficult trap situations and to the designated target. Note that the communication bandwidth may be as narrow as only a few hundred Hz.