Human-robot interaction booth with shape-from-silhouette-based real-time proximity sensor

Industrial robots have been an essential part of production facilities for many years. They allow fast and precise positioning of even the largest loads with very high repeatability. However, there are still many processes which are superiorly or more economically executed by humans. If a component requires several work steps, some of which are better suited to a robot and some to a human worker, cooperation between humans and robots would be beneficial. Due to the enormous power and speed of industrial robots, this poses a considerable risk to the worker. Therefore, tasks to be performed by humans and robots are usually completely decoupled in terms of space or time. We suggest an approach, which allows a human worker to interact safely with a fast industrial robot. We achieve this by constantly monitoring the position of both robot and human and adjusting the robot’s velocity according to its proximity to the worker. We present an interaction booth, which can be entered by a robot arm from the back and a worker from the front such that they can both access the machinery within. A multicamera sensor, which is based on the shape-from-silhouette principle, constantly observes the booth to monitor its occupancy. We demonstrate that within 50 ms, our sensor can (1) detect a change in occupancy in the booth, (2) classify sub-volumes as “robot”, “human”, or “other object”, (3) calculate the distance between human and robot, and (4) output this information to the robot controller. The working speed of the robot is then adjusted according to its distance to the worker.