A Wavelet-Based Approach for Online External Leakage Diagnosis and Isolation from Internal Leakage in Hydraulic Actuators

Goharrizi, Amin Yazdanpanah; Sepehri, Nariman; Wu, Yan

doi:10.1080/14399776.2011.10781029

Cited by 9 publications

(6 citation statements)

References 19 publications

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“…Internal leakage down to 0.2 L/min is detected experimentally on the test setup used in May et al [14]. Goharrizi et al [16] further uses wavelet analysis to detect external leakage and isolates it from internal leakage. External leakage is detected down to 0.3 L/min experimentally where needle valves are used to emulate external and internal leakage.…”

Section: Internal and External Leakagementioning

confidence: 99%

Fault Detection and Diagnosis Methods for Fluid Power Pitch System Components—A Review

2021

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Wind turbines have become a significant part of the global power production and are still increasing in capacity. Pitch systems are an important part of modern wind turbines where they are used to apply aerodynamic braking for power regulation and emergency shutdowns. Studies have shown that the pitch system is responsible for up to 20% of the total down time of a wind turbine. Reducing the down time is an important factor for decreasing the total cost of energy of wind energy in order to make wind energy more competitive. Due to this, attention has come to condition monitoring and fault detection of such systems as an attempt to increase the reliability and availability, hereby the reducing the turbine downtime. Some methods for fault detection and condition monitoring of fluid power systems do exists, though not many are used in today’s pitch systems. This paper gives an overview of fault detection and condition monitoring methods of fluid power systems similar to fluid power pitch systems in wind turbines and discuss their applicability in relation to pitch systems. The purpose is to give an overview of which methods that exist and to find areas where new methods need to be developed or existing need to be modified. The paper goes through the most important components of a pitch system and discuss the existing methods related to each type of component. Furthermore, it is considered if existing methods can be used for fluid power pitch systems for wind turbine.

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Section: Internal and External Leakagementioning

confidence: 99%

Fault Detection and Diagnosis Methods for Fluid Power Pitch System Components—A Review

2021

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“…As opposed to model-based approaches, the use of the wavelet transform by Goharrizi et al (2010aGoharrizi et al ( , 2010b has produced good results by allowing the detection of an internal leakage of 0.124 l/min. But when external leakages were considered in Goharrizi et al (2011), it was reported that external leakages of 0.30 l/min could be isolated from an internal leakage of 0.48 l/min, and furthermore external leakages cannot be localized to either side of the actuator, which has been proven to be possible with model-based approaches .…”

Section: Introductionmentioning

confidence: 96%

Detection and Isolation of Leakage and Valve Faults in Hydraulic Systems in Varying Loading Conditions, Part 2: Fault Detection and Isolation Scheme

Nurmi¹,

Mattila²

2012

International Journal of Fluid Power

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Leakages and valve faults are among the most common faults in hydraulic systems. This paper studies the real-time detection and isolation of certain leakage and valve faults based on the results obtained in part one. In the first part, the mathematical model of a hydraulic test bed was analysed with Global Sensitivity Analysis to facilitate a systematic and verified approach to model-based condition monitoring. In this paper, an Unscented Kalman Filter-based Fault Detection and Isolation scheme for leakage and valve faults of a generic servo valve-controlled hydraulic cylinder is devised. Compared to existing literature, the leakage and valve faults are decoupled from cylinder static and dynamic loading which makes the results generic and applicable to any servo valve-controlled hydraulic cylinder. Moreover, a more comprehensive set of fault patterns for the detection and isolation of leakages and valve faults with experimental and simulation results are presented. We show that detecting an external leakage of as small as 0.17 l/min is possible in some cases, but the accuracy of the method varies considerably. We also report why the isolation of valve faults from leakages is very difficult.

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“…The authors of [26][27][28][29][30] employed wavelet transform and fast Fourier transform to extract signal features and precisely determine a leakage pattern.…”

Section: Introductionmentioning

confidence: 99%

Modelling Internal Leakage in the Automatic Transmission Electro-Hydraulic Controller, Taking into Account Operating Conditions

Dziubak,

Szczepaniak

2023

Energies

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The basic malfunction of automatic transmissions (ATs) is oil flow through hydraulic precision pair clearances called an “internal leakage”, leading to difficulties in controlling the AT. There are no sufficiently accurate methods for assessing the impact of “internal leakage” on the AT technical condition in the course of operation. A proprietary hydraulic precision pair internal leak flow model has been proposed in the paper. The novelty of the model is applying electro-hydraulic controller precision pair clearance values as data that was determined through measurements involving an actual object with a specific AT operation period. The authors conduct variant tests of the model to determine the total AT hydraulic system controller leakage. Reduced oil viscosity (approx. 20%) results in internal leakage increasing by 25%. Significant wear of the controller’s precision pair and increased oil temperature (above 80 °C) lead to internal leakage increasing by more than 50% and oil pressure decreasing below the permissible value.

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A Wavelet-Based Approach for Online External Leakage Diagnosis and Isolation from Internal Leakage in Hydraulic Actuators

Cited by 9 publications

References 19 publications

Fault Detection and Diagnosis Methods for Fluid Power Pitch System Components—A Review

Fault Detection and Diagnosis Methods for Fluid Power Pitch System Components—A Review

Detection and Isolation of Leakage and Valve Faults in Hydraulic Systems in Varying Loading Conditions, Part 2: Fault Detection and Isolation Scheme

Modelling Internal Leakage in the Automatic Transmission Electro-Hydraulic Controller, Taking into Account Operating Conditions

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