A new method for compensation of static deformations of a machine tool

In this article, a new method for compensation of static deformations of a machine tool to improve its working accuracy will be introduced. The compensation is carried out by the feed drives so that the new compensation method does not need any extra actuators. The computation of the compensation movements of the feed drives are based on a deformation model of the machine tool and on measured forces in the feed drives. The static stiffness of parts that are in the flow of the force is the input parameters of the deformation model. These parameters are measured in assembled state by a new measurement procedure so that the new compensation method can be used for already assembled machines. Another input for the computation of the compensation movements is the measured forces in feed drives, from which the load forces on the parts are computed. For this purpose, a multibody model of the machine must be built. Both models, deformation model and multibody model, require the knowledge of the TCP position. It is obvious that the new compensation method does not need any extra sensors. The principle of this compensation method will be demonstrated on a parallel kinematic machine tool