Real-Time Estimation of Temperature Field and Thermal Displacement in Machine Tool Linear Motion Systems Using Servo Data

Heat generated in machine tools during operation causes thermal deformation and deteriorates machining accuracy. To suppress thermal deformation and the resulting displacement, strategies such as reducing heat generation, cooling machine elements that generate heat, and compensating for thermal displacement are generally adopted. However, existing methods for estimating and compensating for thermal deformation and displacement can only be adopted in limited situations. In particular, there are few reports on real-time estimation methods that take into account moving parts and actual machine operating conditions. For high-accuracy machining, it is important to understand the temperature field and the associated displacement. In this study, real-time estimation of the temperature field and displacement is carried out on a test apparatus equipped with a ball screw drive system and a linear guideway system. In the estimation process, heat generation values are first calculated from servo data corresponding to the machine operation. Using these calculated values, the temperature field is then derived through the finite volume method. Finally, the thermal displacement is obtained from the temperature field using a simplified estimation method. The results are validated by comparison with experimental data and with results from commercial finite element method software, demonstrating the effectiveness and real-time performance of the proposed approach.