Artificial Neural Networks (ANN) is implemented to build a maintenance action recommendation system for Bulk Good System (BGS). The BGS contains typical components of an industrial facility that operates with bulk goods i.e. storage containers, conveyors, weighing systems, control systems, sensor technology, Human-Machine-Interface, etc. The proposed ANN-based system can predict machine condition based on the data inputs it gets and recognizes machine trends based on some given features.
4. Problem Statement
Bulk Good System:
Four stations.
Each station has five sensors.
Overall system health determined by individual station health.
Implementation of ANN in MATLAB environment to predict system
health.
Testing, validating and comparing prediction with actual data.
Recommend maintenance action.
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5. Artificial Neural Network (ANN)
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Computing systems inspired by
the biological neural networks.
Based on a collection of nodes
called artificial neurons.
Consist of input layer, hidden
layer and output layer.
Fig: Analogy of ANN with biological neuron
Fig: A simple neural network
6. Understanding datasets
Two normalized datasets: training and testing.
3300 and 1556 readings for training and testing respectively.
Station or system health condition classified as:
1 = Normal (Health = 1)
2 = Warning (Health = 0.8)
3 = Critical (Health = 0.7).
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7. Implementation of ANN
Neural Network Toolbox in MATLAB is used.
Feedforward Backpropagation is used for weights and bias values.
Ten neurons per hidden layer.
TANSIG and PURELIN activation function.
Training data divided into three parts: Training, Validation and Testing.
Performance and regression graph is analysed to detect any overfitting.
Toolbox iterations stop at best mean-squared error (MSE).
After training, the ANN is tested using 1556 set of testing data.
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13. Recommendation System
Code is written using MATLAB for the recommendation system algorithm.
Operator will see the overall system health value.
If health >= 0.9, system is NORMAL.
If health < 0.9 and >= 0.75, system is in WARNING state.
If health < 0.75, system is in CRITICAL state.
Operator’s action is explained by the following flowchart.
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15. Conclusion
System health condition of BGS is predicted using ANN.
Predictions are fairly accurate.
Reliable for future maintenance scheduling.
More training data and more neurons may improve its accuracy.
Other classifier tools such as Bayes classification, SVM can be used.
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Feedforward: In a feed forward network information always moves one direction; it never goes backwards.
Backpropagation: method used in artificial neural networks to calculate a gradient that is needed in the calculation of the weights to be used in the network.