High Dynamic Compensation Mechanism

In work package 4 of the COMET project, the high dynamic compensation mechanism (HDCM) was developed. The aim of the HDCM is to remove the final error sources and reach the set objective of machining with an accuracy of less than 50 ?m, which was achieved for several test parts in laboratory test setups. The main purpose of the cell at Fraunhofer IPA was the research and development of the HDCM component. The compensation consists of real time correction after measuring the misalignment between programmed and real robot position, measured with the ATIR system. The measured corrections are sent back to TwinCAT CNC robot controller to adjust end effector position which holds the machined part. Besides this correction, the spindle position is also adjusted moving the HDCM. The concept is based on a smart splitting of the positioning correction, sending to the robot controller the wider and lower-frequency corrections and leaving the HDCM to manage the smaller and higher-frequency corrections. The compensation range for the HDCM is around 400 ?m and in order to have it working properly, the robot end effector accuracy reached with the feedback control from the ATIR system need to be below ± 200 ?m. The knowledge gained in the R&D is the main exploitable result for Fraunhofer IPA. The manufacturing of the HDCM components was achieved by partner NISAFORM, which contained some challenging geometries to be machined and manufactured. The manufacturing experience is now available at NISAFORM.