A method for cutting force estimation through joint current signals in robotic machining

Abstract

Industrial robots have been playing a key role in many sectors for several decades, enabling higher automation levels. Lately, they have upscaled their role in the manufacturing industry. Apart from handling and assembly tasks, robots are being directly involved in manufacturing processes, due to their large working envelopes and high flexibility. Process monitoring is a crucial task since it enables real-time characterization and control. Especially in the case of robots, cutting forces cause deflection of the arm and subsequently dimensional errors. As a result, estimating these forces is a significant task. This is the main shortcoming of robots in machining and should be compensated in real-time. However, utilizing costly dynamometers for this purpose is often not feasible on an industrial level. This work proposes a method for extracting cutting forces from the joint current signals, which are already monitored by the robot controller, to enable cost-effective and non-invasive force monitoring.