Hybrid correction of thermal errors using temperature and deformation sensors

Thermo-elastic deformations are one of the most significant sources of production inaccuracies in cutting machine tools today. There are numerous methods to model, monitor and correct or compensate these thermal errors in machine tools. Among the indirect correction methods count the characteristic diagram based correction and the correction based on integral deformation sensors (IDS). Both are briefly described and their strengths and weaknesses are discussed. Following this, ways of combining both methods to overcome their respective weaknesses are discussed. A hybrid correction method is proposed which uses characteristic diagrams to derive a relationship between online IDS measurements and the actual tool-center-point (TCP) displacement. Experiments carried out on a 3-axis machine tool demonstrate the effectiveness of both correction methods.