Cooperative bin-picking with Time-of-Flight camera and impedance controlled DLR lightweight robot III

Abstract

Because bin-picking effectively mirrors great challenges in robotics, it has been a relevant robotic showpiece application for several decades. In this paper we describe the computer vision algorithms in combination with the sophisticated control schemes of the robot and demonstrate a reliable and robust solution to the chosen problem. This paper approaches the bin-picking issue by applying the latest state-of-the-art hardware components, namely an impedance controlled lightweight robot and a Time-of-Flight camera. Lightweight robots have gained new capabilities in both sensing and actuation without suffering a decrease in speed and payload. Time-of- Flight cameras are superior to common proximity sensors in the sense that they provide depth and intensity images in video frame rate independent of textures. The bin-picking solution presented in this paper aims at extending the classical bin-picking problem by incorporating an environment model and allowing for the physical human-robot interaction during the entire process. Existing imprecisions in Time-of-Flight camera measurements and environment uncertainties are compensated by the compliant behavior of the robot. The overall process is implemented in a generic state machine that also monitors the entire bin-picking process.