Fault diagnosis and recovery for a CNC machine tool thermal error compensation system

The major role of temperature sensors in a machine tool thermal error compensation system is the improvement of machining accuracy through the supply of reliable temperature data on the machine structure. This paper presents a new method for the fault diagnosis of temperature sensors along with the recovery of faulty data, thereby protecting the reliability of a thermal error compensation system. The proposed method of detecting a fault and its location is based on the correlation coefficients among the temperature data produced by the sensors. Thereafter, a multiple linear regression model, prepared using the complete normal data, is used for the recovery of faulty data. The effectiveness of this method was tested by comparing computer simulation results with measured data from a CNC machining center.