Failure Monitoring and Predictive Maintenance of Hydraulic Cylinder—State-of-the-Art Review

A hydraulic cylinder is a mechanical actuator that is widely used in different industries such as construction, manufacturing, aerospace, and offshore oil and gas. Seal wear in hydraulic cylinders results in hydraulic fluid leakage or contamination of the hydraulic fluid. Untimely, failure of a hydraulic cylinder increases the maintenance cost and reduces productivity. Therefore, condition monitoring of the hydraulic cylinder is necessary to understand the current state of equipment. In the literature, there have been numerous documented attempts to perform condition monitoring of hydraulic cylinders using different methods, based on fluid properties, pressure, vibration, and acoustic emission. However, there have been limited attempts to present a state-of-the-art review of condition monitoring of hydraulic cylinders. This article presents an overview of the methods used for the condition monitoring of hydraulic cylinders, including the detection of different failure modes using different sensors, the separability of fault conditions using sensor-based features, and the ability to pick up incipient faults by sensor-based features. This information is required for new readers in this area of expertise. This article summarizes different condition monitoring methods that have been used from its early implementation to very recent dates, aiming at clarifying recent advances and identifying challenges in the research of the condition monitoring of hydraulic cylinders. It is anticipated that the information presented in this article will be beneficial for new researchers and provide directions for future research in the area of condition monitoring of hydraulic cylinders.