Further development and implementation of a model-based, integratable multi-sensor system for automatic and process parallel determination and compensation of the volumetric error at the functional point (AutoKomp II)

• Applicant: Professor Dr.-Ing. Robert Schmitt
• Subject Area: Production Automation and Assembly Technology ; Automation, Mechatronics, Control Systems, Intelligent Technical Systems, Robotics ; Measurement Systems
• Term: from 2016 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 298597595

The trend in production technology towards more efficient component manufacturing with increasingly complex geometries and shrinking tolerances is unbroken due to the advancing technological development. The positioning accuracy of the machine tool is essential for component quality. Any deviation of the machine movement from the nominal movement at the functional point (volumetric error) is transferred to the workpiece and results in shape deviations. A state of the art industrial method for increasing precision without cost-intensive design changes or mechanical settings is the calibration of the machine tool, i.e. measuring the machine errors, with subsequent control-based compensation. Since the movement deviations of the machine tool vary depending on the process, temperature, load and wear, static compensations lose their validity within short periods of time (in extreme cases a few hours). Although regular repetitions of the calibration are established in industry, they are insufficient due to the high variability of the motion deviation and at the same time cause high costs. In addition, there are numerous methods in research and industry to compensate for the variability of individual geometric errors. Still, there is no overall model for the practical application to all relevant static and elastic effects. To maximize the economic benefit of calibrations and to avoid costly and energy-intensive air conditioning, time-discrete calibrations and the process-parallel recording of machine states as well as the different modelling approaches should effectively combined. The aim of the second phase of the overall project applied for here is the further development and implementation of a model-based, integratable multi-sensor system for automatic and process parallel determination and compensation of the volumetric error at the functional point. Based on the sensor design for the process-parallel detection of geometric errors within a linear axis, which was developed and validated in phase one, the entire test machine is to be equipped with appropriate sensors. In addition, further sensors will be used to record machine and environmental conditions, such as the deformation of structural components and temperature distribution. Direct measurements of the volumetric error will be added as time-discrete inputs for the setup, adjustment and validation of an overall model, whereby the time intervals for this must be maximized. This multi-sensor system then provides data for a hybrid overall model approach, which on the one hand takes into account existing and industrially established methods, but also attempts to combine the advantages of modern white-box and black-box modelling. The project will be tested and validated on a test machine for one year before it is to be transferred to other machine types and into productive operation in phase three.

• DFG Programme: Research Grants