3-D-piezo-compensation mechanism for error compensation enables high-accurate robot machining processes

This paper introduces a new and innovative method for machining with an industrial robot. Today, tasks for a typical robot application are simple handling jobs such as pick-and-place from place A to B. For such pick-and-place operations the robot's repeatability is good enough. Nevertheless, complex, flexible and precise handling systems are required. Specifically the market for tasks of dynamically processing, e.g. machining with robots has been growing recently. So the idea is to use the robot for those tasks since conventional metal cutting machine tools are higher in price and more inflexible compared to robot applications. Thus, this article describes the development of a 3-D-Piezo-Compensation-Mechanism (3-D-PCM) due to the idea of online error compensation. Aspects and rules related to the design of an actuation mechanism based on elastic solid-state joints (ESSJ) are presented. The results of the iteratively finite element analysis (FEA) and designing are following along with its static and dynamic results. Finally, the manufactured and on a testbed installed 3-D-PCM will be shown. The beneficiaries of this robot machining concept will be presented finally by showing first machined work-pieces and measured results of those, respectively.