OPTIMAL POSITIONING METHODS OF INTEGRAL DEFORMATION SENSORS – EXPERT KNOWLEDGE VERSUS MATHEMATICAL OPTIMIZATION

  • 1RWTH Aachen University, Laboratory for Machine Tools and Production Engineering (WZL), Aachen, Germany, Aachen, DE
  • 2TU Chemnitz, Faculty of Mathematics, Chemnitz, Germany, Chemnitz, DE
  • 3Fraunhofer Institute of Production Technology (IPT), Aachen, Germany, Aachen, DE

Abstract

Up to 75 % of the overall work piece error can be caused by the thermo-elastic behavior of the machine tool. Therefore, correction methods based on machine-integrated sensors were intensively researched during the last years, in order to determine the error of the Tool Center Point (TCP) parallel to the process. One of these methods includes the integral deformation sensor (IDS), which detects the deformation along the length of a structural component of the machine. The error of the TCP is modelled based on the measured structural deformations, a mechanical model of the structural parts and a kinematic model of the machine tool. Currently, the sensor setup for specific machines is usually defined by an expert with the help of his or her domain knowledge. There are existing mathematical methods for optimal sensor positioning. The aim of this work is the evaluation of the expert positioning versus the mathematical methods. The parameters to be varied are the lengths and positions of the IDS. Criteria for the evaluation are the achievable accuracy of the TCP error prediction and the sensitivity to small variations of the optimal position, as they might occur during the installation.

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