1 INTRODUCTION
In a raw meal grinding process, the particle size of the raw meal is directly related to quality of final products. However, it is difficult to be measured by sensors. In practical production process, the particle size of the raw meal is measured off-line once an hour, then an operator adjusts the separator frequency and materials ratio to control particle size of raw meal. However, there is a large lag for off-line detection as well as subjective analysis error. Therefore, according to the measurement off-line, it is hard to control efficiently the particle size of raw meal. The measurable auxiliary variables are used to develop a fuzzy neural network(FNN) model.