Advanced off-line simulation framework with deformation compensation for high speed machining with robot manipulators

In this paper, we present a complete off-line modelling and simulation framework with deformation compensation for accurate robot milling of workpieces. We consider two previously published methods for deformation modelling into our framework: A method containing a model for predicting the milling forces acting on the robot based on the net energy consumption of the milling device. The other method computes robot deflections due to these external forces using joint stiffness models. We illustrate how the methods are incorporated into our framework and we provide resulting accuracies obtained from experimental studies. For these studies we use a KUKA KR120 QUANTEC pro robot with a high speed milling tool working in aluminum 3003. We experimentally calibrate the unknown parameters in the joint stiffness model and the milling force prediction model. We then show experiments that verify that we by compensating for deviations, we can improve the accuracy to reach a value similar to the theoretical lower limit given by the precision specified by the robot manufacturer.