Abstract
We consider fault detection in a hydraulic system that maintains multivariate time-series sensor data. Such a real-world industrial environment could suffer from noisy data resulting from inaccuracies in hardware sensing or external interference. Thus, we propose a real-time and robust fault detection method for hydraulic systems that leverages cooperation between cloud and edge servers. The cloud server employs a new approach that includes a genetic algorithm (GA)-based feature selection that identifies feature-to-label correlations and feature-to-feature redundancies. A GA can efficiently process large search spaces, such as solving a combinatorial optimization problem to identify the optimal feature subset. By using fewer important features that require transmission and processing, this approach reduces detection time and improves model performance. We propose a long short-term memory autoencoder for a robust fault detection model that leverages temporal information on time-series sensor data and effectively handles noisy data. This detection model is then deployed at edge servers that provide computing resources near the data source to reduce latency. Our experimental results suggest that this method outperforms prior approaches by demonstrating lower detection times, higher accuracy, and increased robustness to noisy data. While we have a 63% reduction of features, our model obtains a high accuracy of approximately 98% and is robust to noisy data with a signal-to-noise ratio near 0 dB. Our method also performs at an average detection time of only 9.42 ms with a reduced average packet size of 179.98 KB from the maximum of 343.78 KB.
Highlights
Hydraulic systems are utilized in several industrial applications, including manufacturing, automobiles, and heavy machinery [1,2,3,4,5]
We propose an long short-term memory autoencoder (LSTM-AE) as the fault detection model to learn the temporal relations in the time-series data and extract latent features from noisy data
Each figure shows the sensor data applied with a different noise degree in the signal-to-noise ratio (SNR), as defined in Equation (3), where Pnoise represents the power of the noise, and Psignal represents the power of the signal:
Summary
Hydraulic systems are utilized in several industrial applications, including manufacturing, automobiles, and heavy machinery [1,2,3,4,5]. The concept of Industry 4.0 [10] is proposed as the current state-of-the-art among IT and manufacturing that offers enhancements in product quality, real-time decision-making, and integrated systems. Cooperation between cloud and edge servers must occur for real-time fault detection in hydraulic systems [14]. The cloud server can utilize offline learning, such as selecting the important data to transfer and performing model training, while the real-time intelligent service of fault detection is executed on the edge server. The cloud performs feature selection and offline learning, and the edge computes online detection near the data source, which together reduces latency and transmission costs.
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