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A typical configuration of planetary gear-set with 4 equally spaced planet pinions and an accelerometer mounted on the stationary annulus gear.
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The application of conventional vibration based diagnostic techniques to planetary gearboxes is a challenge because of the complexity of frequency components in the measured spectrum, which is the result of relative motions between the rotary planets and the fixed accelerometer. In practice, since the fault signatures are usually contaminated by no...
Citations
... x x x Li_2016e [362] x p2 x x Hong_2016 [363] x x p4 ...
Monitoring vibrations in rotating machinery allows effective diagnostics, as abnormal functioning states are related to specific patterns that can be extracted from vibration signals. Extensively studied issues concern the different methodologies used for carrying out the main phases (signal measurements, pre-processing and processing, feature selection, and fault diagnosis) of a malfunction automatic diagnosis. In addition, vibration-based condition monitoring has been applied to a number of different mechanical systems or components. In this review, a systematic study of the works related to the topic was carried out. A preliminary phase involved the analysis of the publication distribution, to understand what was the interest in studying the application of the method to the various rotating machineries, to identify the interest in the investigation of the main phases of the diagnostic process, and to identify the techniques mainly used for each single phase of the process. Subsequently, the different techniques of signal processing, feature selection, and diagnosis are analyzed in detail, highlighting their effectiveness as a function of the investigated aspects and of the results obtained in the various studies. The most significant research trends, as well as the main innovations related to the various phases of vibration-based condition monitoring, emerge from the review, and the conclusions provide hints for future ideas.
... The unexpected failures of planetary gearboxes will lead to increased downtime and structural damage. The condition monitoring of planetary gearboxes has received intensive research in the past decade due to its demand in heavy industrial applications [1,2]. It is very important to diagnose the early degradation of gears and bearings to prevent catastrophic accidents and production loss. ...
Condition monitoring of machine is recognized as effective strategy for undertaking the maintenance in wide variety of industries. Planetary gearbox is a critical component in helicopters, wind turbines, hybrid vehicles and so forth. Planetary gearbox are complex in nature due to its size and meshing components. Condition monitoring and fault diagnosis of planetary gearbox is challenging due to complexity in dependable fault extraction from raw vibration signal. The mechanism of planetary gearbox is complex as there are several gears meshing at the same time. To find out the nature of fault and defective component in planetary gearbox is difficult. In this paper, the fault detection and fault type identification diagnostic approach using auto regression model (AR) and continuous wavelet transforms (CWT) by considering different frequency range is established. The experimental research conducted with different type of fault vibration signals in the gearbox have been diagnosed and identified the fault type using AR Modelling, Impulse and Shape Factor for validation purposes. The unique behaviors and fault characteristics of planetary gearboxes are identified and analyzed. The fault frequency identification and extraction of features from the non-stationary signals in different fault severity level of vibration data demonstrates the reliability of proposed method. The developed algorithm adds efficacy in detecting the nature of fault and defective component without performing a visual inspection.
... The test of gear static geometric precision cannot reach the increasing low noise requirement [6,7]. In general, the geometrical errors of the gears are intertwined with each other and interact with the operating conditions of the gears [8][9][10]. Therefore, it is necessary to predict the dynamic performance of gear during the design and manufacture, and the dynamic performance of gear can be detected before use. ...
With the development of gears towards high temperature, high pressure, high speed and high stress, gear measurement, in which only the static geometric accuracy is considered, is unable to meet the current application requirements. While, the low precision and single function gear tester constrains the measurement of gear dynamic performance. For the resolution of this problem, based on the principle of gear system dynamics and several precision mechanical design techniques, a gear dynamic testing machine has been developed, providing new instruments for gear testing. On the basis of research of the principle of dynamic performance test, the primary measurement items of the testing machine have been determined. The measuring principles of each item and the driving and loading form of the testing machine have been examined. The measurement and control system of the testing machine and its corresponding software have been developed. The instrument can not only obtain the static precision index of the gear, but also obtain the dynamic performance index of the gear in variable working conditions. According to the actual test, the uncertainty of instrument is 3.8 μm and the external disturbance caused by the shaft vibration is less than 0.6 μm, which can meet the 5–6 grade precision gear testing requirement.
... These vibration signals in the presence of faults can be affected by these paths by the undesirable interference and make it complicated [5,6] for analysing the same. Hence the complex vibration signals from the conventional fixed type accelerometer make the vibration based fault diagnosis method for planetary gearbox more challenging [7]. The shortcoming of the traditional method can be omitted by installing an on-rotor MEMS accelerometer on the rotating shaft directly that can provide a constant distance from accelerometer to the mating gears with a good dynamic response [8,9,10], thus making it an alternative cost effective approach to an expensive conventional accelerometer. ...
... Ligata [18] proposed a discrete model for calculating the static inhomogeneous coefficient, and derived a formula for calculating the static unequal load factor of four sets of planetary gears. With respect to experiments, Hong [19] integrated the analytical model, a denoising algorithm, and frequency domain indicators into one synergistic system to detect and identify the damaged gear teeth in the planetary gearboxes. A planetary gearbox test rig validated the dynamic simulations and the experimental data. ...
... ( ) sin y t A ωt (18) ( ) cos cos y t Aω ωtv ωt (19) Based on the above analysis, the mathematical model corresponding to the mechanical conditions in Table 6 ...
A rotary driving component is the power output unit of a lunar sampler. A planetary gear system is used as the transmission system. The lunar sampler is subjected to an extremely rigorous mechanical environment during transportation. In this study, the time-varying meshing stiffness curves of planetary gears are calculated by Shi Chuan method. A translational torsional dynamic model of a twostage planetary gear system is established. Based on the Runge–Kutta method, solution program is used to obtain the inherent characteristics of the transmission, and corresponding verification tests are performed. With respect to the transportation process (i.e., the stage between launch and landing), the dynamic response of the transmission is examined. With respect to adverse geological conditions, the load sharing characteristics of the transmission are calculated. The aforementioned investigations provide a theoretical basis for parameter setting and structural design of a lunar exploration project.
... A review study on the methodologies of planetary gearbox condition monitoring and fault diagnosis is presented in [4] and, according to this study, most planetary gearbox diagnostic systems have used the vibration signal measured by an accelerometer mounted on the housing of the planetary gearbox. Generally, this vibration signal, z(t), contains valuable diagnostic information regarding the planetary gear-set, and can be considered as the superposition of vibrations from planets meshing with the annulus and sun gear [5] ...
... The window function ωi(t) is used to describe the amplitude modulation phenomenon caused by the relative motion between the fixed accelerometer and the rotating planets within the carrier [5,6]. This phenomenon can be explained as follows: as a planet rotates and becomes closer to the fixed accelerometer, its vibration dominates the sensory data and the level of its impact reaches a peak when the planet is almost under the accelerometer; thereafter, it decreases as the planet moves away from the accelerometer. ...
... The signal xi(t) in (1) denotes the vibration resulting from the gear and i th planet mesh, which is periodic at the fundamental gear mesh frequency fm, whilst the yi(t) indicates the vibration resulting from the sun gear and i th planet mesh, which is also periodic at the fundamental gear mesh frequency fm. As a result, the sidebands in the measured vibration signal sensed by a fixed accelerometer have a complex nature, which makes the application of conventional vibration-based diagnostic techniques to planetary gearboxes a challenge [5]. This issue can be solved by employing an accelerometer directly on the rotating shaft, providing a constant distance between the accelerometer and the rotating planets. ...
... A review study on the methodologies of planetary gearbox condition monitoring and fault diagnosis is presented in [4] and, according to this study, most planetary gearbox diagnostic systems have used the vibration signal measured by an accelerometer mounted on the housing of the planetary gearbox. Generally, this vibration signal, z(t), contains valuable diagnostic information regarding the planetary gear-set, and can be considered as the superposition of vibrations from planets meshing with the annulus and sun gear [5]. ...
... The window function ωi(t) is used to describe the amplitude modulation phenomenon caused by the relative motion between the fixed accelerometer and the rotating planets within the carrier [5,6]. This phenomenon can be explained as follows: as a planet rotates and becomes closer to the fixed accelerometer, its vibration dominates the sensory data and the level of its impact reaches a peak when the planet is almost under the accelerometer; thereafter, it decreases as the planet moves away from the accelerometer. ...
... The signal xi(t) in (1) denotes the vibration resulting from the gear and i th planet mesh, which is periodic at the fundamental gear mesh frequency fm, whilst the yi(t) indicates the vibration resulting from the sun gear and i th planet mesh, which is also periodic at the fundamental gear mesh frequency fm. As a result, the sidebands in the measured vibration signal sensed by a fixed accelerometer have a complex nature, which makes the application of conventional vibration-based diagnostic techniques to planetary gearboxes a challenge [5]. This issue can be solved by employing an accelerometer directly on the rotating shaft, providing a constant distance between the accelerometer and the rotating planets. ...
