Experiments on telemanipulation with ‘delayed live’ video

Abstract

Bilateral master-slave tele-manipulation from a remote control console is an interactive operation whose success, to a large extent, depends on the operator's agility and experience. The operator requires two-way communication - velocity commands to the robot to move it and the force-feedback signal to the operator to detect collision. The operator's corrective actions are based on the live images from the site, displayed on a video monitor. Thus, the operator's action virtually establishes a position control loop. However, the delayed video images shown to the operator often results in undesirable correction commands, similar to the consequences one would expect from a delayed feedback. This is due to the fact that the cameras and the network have limited frame rate for relaying and reconstructing the images. We present here an experimental system, where we try to reinterpret the operator's intentions with the knowledge of robot's current posture and force sensor's data which are transmitted using wave variables to mitigate the effects of transmission delay. We try this method in an industrial KUKA™ robot serving as a slave robot with due consideration of the fact that its control hardware is not accessible to the user.