In this paper, neuro based intelligent diagnosis methods for electro-mechanical control
system are proposed. A self organizing map neural network (SOM) is used to classify
measured data of the target system as a qualitative diagnostic method. Besides of the above
procedure, it is expected to attain more efficient maintenance by a quantitative estimation
of failure. For the purpose, new method is proposed using a hierarchical neural network
(HNN). In the method, classified results by SOM are processed for the quantitative diagnosis.
Hierarchical neural network can identify inner structure of the relations between failure
causes and its results that enables a quantitative diagnosis