The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In planetary gearbox operation, there are many uncertain factors that may result in incomplete diagnostic information, such as measurement instrument faults, limitation of transmission capacity, and data processing. Therefore, it has been one of the greatest obstacles to fault diagnosis of planetary gearbox. To address this issue, a novel fault diagnosis method of planetary gearbox with incomplete...
Planetary gearbox of wind turbine works under changed load and speed and the vibration signal is nonlinear, non-stationary, this make it difficult to extract the weak fault characteristic frequency. In this paper, a new method of fault feature extraction and separation based on empirical mode decomposition (EMD) and resonance demodulation is proposed. The method uses EMD to decompose the vibration...
In order to study the theory and characteristics of the mechanical drive system fault in the current signal of the wind turbine generator better, the fault simulation experimental platform of double fed wind generator drive gear is used as the research object, and the simulation model of double motor torque and rotational speed coupling is established by a motor and a doubly fed wind generator according...
In order to study the response mechanism for motor stator current signal to mechanical vibration fault signal, taking the local of impact fault detection in rolling bearing outer ring as an example, using the theory of Hertz elastic collision, when the rolling body through the local fault of the outer ring, the impact torque mechanical model of instantaneous and the large of amplitude are established...
In the fault diagnosis method of the resonance demodulation of the planetary gear of the wind turbine, there are some shortcomings like artificial difficulties in demodulation band and low demodulation spectral resolution. In this paper, wavelet packet decomposition and reconstruction method are used effectively to extract the resonance frequency components caused by the local fault of gear, which...
Aiming at the problem that the mechanical fault information of the transmission system of the wind turbine is weak in the stator voltage and current signals, and it is difficult to identify and extract, a new method of electrical signal preprocessing-instantaneous power of demodulation method has been proposed. And use the DSP to achieve the portable data acquisition and diagnosis system. By using...
In order to solve the problem of accurate simulation modeling and equation solving difficulties of asynchronous motor broken bar fault. By using the simulation module of the winding asynchronous motor, establish the simulation model of the simple broken bar fault in the SIMULINK environment. We discuss the motor current fault diagnosis method of broken bars fault by changing the external resistors...
In order to discuss the application of sensorless diagnosis in the fault diagnosis of wind power generator. A method which is different from the traditional model of wind turbine generator system is proposed. A simulation model of wind power generator is established based on MATLAB/SIMULINK, the dynamic simulation model of transmission gear in normal and fault condition is established based on ADAMS...
The problem that the mechanical fault information of wind turbine generator is weak in the voltage and current signals need to be solved, information is not conducive to the identification and extraction. According to the common algorithm, the instantaneous power and other parameters are combined well, and we exploit the characteristic of mechanical fault information which is used in the same phase...
In order to realize on-line monitor and diagnosis of the fault of the gearbox of a wind driven generator a method of automatic selection frequency-band based on wavelet analysis and kurtosis rule has been put forward. Firstly, a vibration signal is multiple discomposed by using wavelet transformation, and then the kurtosis for wavelet coefficients of different frequency bands is computed and compared...
In order to strengthen engineering background of theory teaching of mechanical major, a virtual experiment platform based on LabVIEW for fault diagnosis of rotating machinery is developed. It can be used as engineering examples demonstration in theory teaching. Additionally, It can be connected with testing system through the interface of NI-DAQ to complete mechanical fault simulation, acquisition...
In order to improve the detection accuracy and stability of the damping ratio parameter of boxed milk quality fast detector, according to wavelet transform theory, this paper presents a method that wavelet ridge is used to extract the envelope curves of the detector torsion response curves, and then take the logarithm to fit a straight line to get the damping ratio of the system, and thus use the...
According to wavelet de-noising and the Hilbert transform theory, a boxed-milk metamorphism rapid detection device and identification method are proposed. Wavelet de-noising method is used to eliminate signal noise, then the use of Hilbert transform for envelope Ways to achieve signal envelope curve, and then for the system damping ratio. Under the case that the package of liquid boxed milk is not...
The conventional PID control of most processes has good control effect and robustness. Without adaptive capacity and prone to elicit inertia delay, this method can only be applied in a special working condition. This paper puts forward a composite fuzzy PID control method based on the establishment of fuzzy rules and the compound of PID controller, as well as the cascade PID controller regulation...
In order to improve the detecting accuracy of the fast-detection device of the UHT(Ultra Heat Treated) box milk quality, the method of wavelet de-noising is applied to the free damped torsional vibration signals produced by the liquid milk box. And by getting the envelope demodulation using the Hilbert transform, the damping ratio of the system is finally calculated. Under the case that the package...
To settle the problems of high-cost detection and complicated fixture of sensors in fault diagnosis, a sensorless method for the detection of torsional vibration based on the current of the motor’s stator is proposed aiming at the mechanical equipment driven by AC induction motors. Computer simulation model is set up using SIMULINK and the analysis of computer simulation is carried out. A test device...
In order to solve the less fault frequencies and unsymmetrical sideband problem in the usual modulation signal of zoom spectrum, according to the principle of modulation frequency shift keying, advance real modulation frequency shift keying algorithm which can realize frequency range and frequency spectrum symmetry. After filtering and re-sampling the real modulation result, making use of the Hilbert...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.