The Experts below are selected from a list of 3753 Experts worldwide ranked by ideXlab platform
Patrick S K Chua - One of the best experts on this subject based on the ideXlab platform.
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fault degradation assessment of water Hydraulic Motor by impulse vibration signal with wavelet packet analysis and kolmogorov smirnov test
Mechanical Systems and Signal Processing, 2008Co-Authors: H X Chen, Patrick S K ChuaAbstract:Abstract The machinery fault diagnosis is important for improving reliability and performance of systems. Many methods such as Time Synchronous Average (TSA), Fast Fourier Transform (FFT)-based spectrum analysis and short-time Fourier transform (STFT) have been applied in fault diagnosis and condition monitoring of mechanical system. The above methods analyze the signal in frequency domain with low resolution, which is not suitable for non-stationary vibration signal. The Kolmogorov–Smirnov (KS) test is a simple and precise technique in vibration signal analysis for machinery fault diagnosis. It has limited use and advantage to analyze the vibration signal with higher noise directly. In this paper, a new method for the fault degradation assessment of the water Hydraulic Motor is proposed based on Wavelet Packet Analysis (WPA) and KS test to analyze the impulsive energy of the vibration signal, which is used to detect the piston condition of water Hydraulic Motor. WPA is used to analyze the impulsive vibration signal from the casing of the water Hydraulic Motor to obtain the impulsive energy. The impulsive energy of the vibration signal can be obtained by the multi-decomposition based on Wavelet Packet Transform (WPT) and used as feature values to assess the fault degradation of the pistons. The kurtosis of the impulsive energy in the reconstructed signal from the Wavelet Packet coefficients is used to extract the feature values of the impulse energy by calculating the coefficients of the WPT multi-decomposition. The KS test is used to compare the kurtosis of the impulse energy of the vibration signal statistically under the different piston conditions. The results show the applicability and effectiveness of the proposed method to assess the fault degradation of the pistons in the water Hydraulic Motor.
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Adaptive wavelet transform for vibration signal modelling and application in fault diagnosis of water Hydraulic Motor
Mechanical Systems and Signal Processing, 2006Co-Authors: H X Chen, Patrick S K ChuaAbstract:Abstract There has been an increasing application of water Hydraulics in industries due to growing concern on the environmental, health and safety issues. The fault diagnosis of water Hydraulic Motor is important for improving water Hydraulic system reliability and performance. In this paper, fault diagnosis of water Hydraulic Motor in water Hydraulic system is investigated based on adaptive wavelet analysis. A novel method for modelling the vibration signal based on the adaptive wavelet transform (AWT) is proposed. The linear combination of wavelets is introduced as wavelet itself and adapted for the particular vibration signal, which goes beyond adapting parameters of a fixed-shape wavelet. The AWT procedure based on the parametric optimisation by genetic algorithm (GA) is developed. The model-based method by AWT is applied to extract the features in the fault diagnosis of the water Hydraulic Motor. This technique for de-noising the corrupted simulation signal shows that it can improve the signal-to-noise ratio of the vibration signal. The results of the experimental signal demonstrate the characteristic vibration signal details in fine resolution. The magnitude plots of the continuous wavelet transform (CWT) show the characteristic signal's energy in time and frequency domain which can be used as feature values for fault diagnosis of water Hydraulic Motor.
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dynamic vibration analysis of a swash plate type water Hydraulic Motor
Mechanism and Machine Theory, 2006Co-Authors: H X Chen, Patrick S K ChuaAbstract:This paper presents the study of the dynamic analysis of a swash-plate water Hydraulic Motor in a modern water Hydraulic system. A swash-plate mechanism is modeled as a system with three masses and 14 degrees of freedom (DOF). In order to evaluate the applicability of the dynamic model, the numerical simulation analysis of the dynamic response of the model due to pressure pulsation is presented and compared with experimental results. A series of the dynamic vibration characteristics of the water Hydraulic piston Motor are studied by the numerical simulation. It is effective for the model to simulate the vibration signal of the casing in the Hydraulic Motor. The waveform and frequency of the simulated signal is similar to the experimental signal. The simulated signals in other directions show that the vibration signals in all the directions mainly consist of the Hydraulic pump and Hydraulic Motor rotational frequencies.
H. Stern - One of the best experts on this subject based on the ideXlab platform.
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Robust controller design for a variable displacement Hydraulic Motor
Proceedings of the 1998 American Control Conference. ACC (IEEE Cat. No.98CH36207), 1998Co-Authors: M.j. Plahuta, M.a. Franchek, H. SternAbstract:Presents the robust control of a variable displacement Hydraulic Motor (VDHM). A feedback control structure consisting of two nested loops is employed. The inner feedback loop controls the position of the rocker arm which actuates the wobbler plate of the Motor. The outer feedback loop regulates the Motor shaft velocity such that shaft speed is guaranteed at steady state despite external torque loads. The control loops are closed in succession closing the inner loop first. For each loop design, step response data is collected from a VDHM laboratory test stand to generate analytical systems level models. Based on these models, feedback controllers are designed using classical loop shaping techniques. Feedback control, as opposed to feedforward control, maintains Motor shaft velocity under nonpredictive torque loading conditions. In addition, the feedback structure eliminates the need for extensive system calibration when considering system parameter changes that result from component aging.
H X Chen - One of the best experts on this subject based on the ideXlab platform.
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fault degradation assessment of water Hydraulic Motor by impulse vibration signal with wavelet packet analysis and kolmogorov smirnov test
Mechanical Systems and Signal Processing, 2008Co-Authors: H X Chen, Patrick S K ChuaAbstract:Abstract The machinery fault diagnosis is important for improving reliability and performance of systems. Many methods such as Time Synchronous Average (TSA), Fast Fourier Transform (FFT)-based spectrum analysis and short-time Fourier transform (STFT) have been applied in fault diagnosis and condition monitoring of mechanical system. The above methods analyze the signal in frequency domain with low resolution, which is not suitable for non-stationary vibration signal. The Kolmogorov–Smirnov (KS) test is a simple and precise technique in vibration signal analysis for machinery fault diagnosis. It has limited use and advantage to analyze the vibration signal with higher noise directly. In this paper, a new method for the fault degradation assessment of the water Hydraulic Motor is proposed based on Wavelet Packet Analysis (WPA) and KS test to analyze the impulsive energy of the vibration signal, which is used to detect the piston condition of water Hydraulic Motor. WPA is used to analyze the impulsive vibration signal from the casing of the water Hydraulic Motor to obtain the impulsive energy. The impulsive energy of the vibration signal can be obtained by the multi-decomposition based on Wavelet Packet Transform (WPT) and used as feature values to assess the fault degradation of the pistons. The kurtosis of the impulsive energy in the reconstructed signal from the Wavelet Packet coefficients is used to extract the feature values of the impulse energy by calculating the coefficients of the WPT multi-decomposition. The KS test is used to compare the kurtosis of the impulse energy of the vibration signal statistically under the different piston conditions. The results show the applicability and effectiveness of the proposed method to assess the fault degradation of the pistons in the water Hydraulic Motor.
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Adaptive wavelet transform for vibration signal modelling and application in fault diagnosis of water Hydraulic Motor
Mechanical Systems and Signal Processing, 2006Co-Authors: H X Chen, Patrick S K ChuaAbstract:Abstract There has been an increasing application of water Hydraulics in industries due to growing concern on the environmental, health and safety issues. The fault diagnosis of water Hydraulic Motor is important for improving water Hydraulic system reliability and performance. In this paper, fault diagnosis of water Hydraulic Motor in water Hydraulic system is investigated based on adaptive wavelet analysis. A novel method for modelling the vibration signal based on the adaptive wavelet transform (AWT) is proposed. The linear combination of wavelets is introduced as wavelet itself and adapted for the particular vibration signal, which goes beyond adapting parameters of a fixed-shape wavelet. The AWT procedure based on the parametric optimisation by genetic algorithm (GA) is developed. The model-based method by AWT is applied to extract the features in the fault diagnosis of the water Hydraulic Motor. This technique for de-noising the corrupted simulation signal shows that it can improve the signal-to-noise ratio of the vibration signal. The results of the experimental signal demonstrate the characteristic vibration signal details in fine resolution. The magnitude plots of the continuous wavelet transform (CWT) show the characteristic signal's energy in time and frequency domain which can be used as feature values for fault diagnosis of water Hydraulic Motor.
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Fault Detection in a Water Hydraulic Motor Using a Wavelet Transform
Journal of Testing and Evaluation, 2006Co-Authors: D. M. R. Mitchell, H X Chen, Psk ChuaAbstract:This paper is concerned with the detection of a piston crack in a water Hydraulic Motor used in a fluid power system. The wavelet-based signal processing technique to detect a piston crack was studied. A complete procedure of wavelet-based vibration signal analysis was developed. A modified noise reduction method based on wavelet analysis for feature extraction of the impulse peak vibration excited by the piston was applied to the vibration data of a water Hydraulic Motor. A continuous wavelet transform (CWT) and a wavelet packet (WP) were applied to the analysis of the impulse vibration signals. The feature values of the peaks excited by the impulse vibration signals can be extracted by using WP to decompose and compress the de-noise signals. Moreover, the signal component indicative of a fault was identified through the analysis of the vibration signal in the time domain in wavelet analysis. This technique was shown to be a powerful tool for the fault detection of a water Hydraulic Motor.
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dynamic vibration analysis of a swash plate type water Hydraulic Motor
Mechanism and Machine Theory, 2006Co-Authors: H X Chen, Patrick S K ChuaAbstract:This paper presents the study of the dynamic analysis of a swash-plate water Hydraulic Motor in a modern water Hydraulic system. A swash-plate mechanism is modeled as a system with three masses and 14 degrees of freedom (DOF). In order to evaluate the applicability of the dynamic model, the numerical simulation analysis of the dynamic response of the model due to pressure pulsation is presented and compared with experimental results. A series of the dynamic vibration characteristics of the water Hydraulic piston Motor are studied by the numerical simulation. It is effective for the model to simulate the vibration signal of the casing in the Hydraulic Motor. The waveform and frequency of the simulated signal is similar to the experimental signal. The simulated signals in other directions show that the vibration signals in all the directions mainly consist of the Hydraulic pump and Hydraulic Motor rotational frequencies.
M.j. Plahuta - One of the best experts on this subject based on the ideXlab platform.
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Robust controller design for a variable displacement Hydraulic Motor
Proceedings of the 1998 American Control Conference. ACC (IEEE Cat. No.98CH36207), 1998Co-Authors: M.j. Plahuta, M.a. Franchek, H. SternAbstract:Presents the robust control of a variable displacement Hydraulic Motor (VDHM). A feedback control structure consisting of two nested loops is employed. The inner feedback loop controls the position of the rocker arm which actuates the wobbler plate of the Motor. The outer feedback loop regulates the Motor shaft velocity such that shaft speed is guaranteed at steady state despite external torque loads. The control loops are closed in succession closing the inner loop first. For each loop design, step response data is collected from a VDHM laboratory test stand to generate analytical systems level models. Based on these models, feedback controllers are designed using classical loop shaping techniques. Feedback control, as opposed to feedforward control, maintains Motor shaft velocity under nonpredictive torque loading conditions. In addition, the feedback structure eliminates the need for extensive system calibration when considering system parameter changes that result from component aging.
A. Kitagawa - One of the best experts on this subject based on the ideXlab platform.
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Versatile water Hydraulic Motor driven by tap water
Proceedings. 2000 IEEE RSJ International Conference on Intelligent Robots and Systems (IROS 2000) (Cat. No.00CH37113), 2000Co-Authors: H. Tsukagoshi, S. Nozaki, A. KitagawaAbstract:This paper proposes new types of a water Hydraulic Motor and a valve to control its speed which will be applied to the robots soaked in water. The big advantage of this Motor is that it can be driven by such low pressure as tap water with high performance. The key of their mechanism is that the working fluid is completely wrapped by the soft tube and their machine moving parts contact the fluid indirectly. In other words, the deformation of the tube drives the Motor, and reversely the valve makes the tube deformed to control the Motor, which removes the risk of leakage without also requiring a seal. In addition, the valve to control the rotational speed is designed which can be driven by fluid power signal without using electricity. The Motors can be used in places where electricity cannot be used safely, such as bathroom, sink, workshop over water, under water, etc. The basic driving principle and characteristics of the theoretical torque, the rotational speed, and the efficiency are described here with the results of the experiment.
