Study on environmental thermal induced error modelling of a stage based on artificial neural network

There are many studies on the displacement error of a stage caused by the internal heat source, but only few studies have been done on the error caused by the external heat source. The displacement error caused by the external heat source called environmental thermal induced error occurs when the stage is affected by the temperature change of the environment due to the external heat source. In order to reduce that error, a method of maintaining a constant environmental temperature has been proposed, but in general working environment, it is difficult to completely control the environmental temperature and error due to various external heat sources. Therefore, the effect of the environmental temperature change on the error of the stage should be analysed first. In this study, we propose a method to model and analyse the environmental thermal induced error of the stage using the artificial neural network(ANN). Several thermal sensors are used to measure the temperature of environment and stage, and a measurement system is used to measure the displacement error of the stage. The above-mentioned measurement process is performed according to the time interval, and an artificial neural network-based error model is established using the measurement data. The proposed model can be applied to evaluate the precision of various stages.