The invention provides a BP (Back Propagation) neural network
algorithm based method for analyzing
coating aging. The method has the advantages of higher flexibility and forecast precision and better hereditability and comprises the processes of
signal forward propagation and error
backward propagation, wherein in the
forward propagation process, an input sample is imported from an input layer and then transmitted to an output layer after the sample is processed through various buried
layers layer by layer; if the actual output of an output layer does not accord with an expected output, the process is turned to an error
backward propagation stage; in the error
backward propagation process, an output error is backwards transmitted to an input layer through the buried
layers in a certain form layer by layer, and the error is shared by all units of all the
layers so as to obtain error signals of all the units of all the layers, wherein the error signals are used as references for correcting the weight values of all the units; and the
weight value adjustment process of all layers of
signal forward propagation and error backward propagation is carried out in cycles until
network output errors are reduced to an acceptable degree or a preset number of times is finished. The method is characterized in that a
momentum item
delta W(t)=eta
delta X+alpha
delta W(t-1) is added, wherein alpha is a
momentum factor alpha belonging to the set of (0, 1); the learning rate is adaptively regulated, if a
total error E rises after the adjustment of a batch of weight values, eta is equal to beta eta (theta>0), and if the
total error E drops after the adjustment of a batch of weight values, eta is equal to theta eta (theta>0); and a steepness factor is introduced, and when an error curve plane enters a flat area, a changed output quantity is set, wherein lambada is the steepness factor, in the flat area, lambada is larger than 1, and after quitting the flat area, lambada is equal to 1.