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A rotary platform is studied in this paper. The control method of its electromechanical transmission system is studied by using virtual prototype technology and control technology. Virtual prototype model of rotary platform is established in the Gear subsystem of RecurDyn, Based on the Hertz elastic contact theory. A feed-forward link and three-ring control system which are position, speed and current...
In this paper we have outlined design considerations and design solutions for a structure of a chameleon-like robot for space applications in space stations. Requirements and characteristics are discussed with the aim to define design problems and operation features that give motivation for a biomimetic inspiration to chameleons. Thus, a study of feasibility is described as referring to a design with...
A novel method for detection and diagnosis the bearing inner and outer race fault according to bi-spectrum analysis technique is presented. The bi-spectrum analysis is widely recognized as an effective technique for machinery fault diagnosis using vibration signals since it can be used to eliminate the effect of strong noise. This advantage makes it very suitable for extracting useful features from...
A novel method for detection and diagnosis of the gear wear fault according to complex Morlet wavelet amplitude and phase map is presented. The continuous wavelet transform is widely recognized as an effective technique for machinery fault diagnosis using vibration signals since it can be used to detect both stationary and transitory signals. This advantage makes it very suitable for the detection...
A novel method for detection and diagnosis the bearing fault according to instantaneous energy spectrum (IES) based on empirical mode decomposition (EMD) method is presented. EMD can adaptively decompose the vibration signal into a series of zero mean oscillatory functions called intrinsic mode functions (IMFs). Hilbert transform can track the instantaneous amplitude and instantaneous frequency of...
The damaged gearbox is often related to non-linear effects that may lead to non-linearity in the machine vibration signal. This paper introduces the application of modern signal processing technique based on higher order spectrum to the fault detection and diagnosis of gearbox. The bi-spectrum can effectively eliminate the effect of random noise and extract useful features from the noisy mechanical...
Varying speed machinery fault diagnosis is more difficult due to non-stationary machine dynamics and vibration. A new approach to fault diagnosis of bearing under running up based on angle domain average and Hilbert-Huang transform (HHT) phase map is presented. The non-stationary vibration signals are transformed from the time domain transient signal to angle domain stationary one using order tracking...
The degree of cyclostationarity technique is introduced and applied effectively to gearbox faults diagnosis under run-up condition. This new method combines order tracking technique with second order cyclo-stationary statistics analysis. The resampling signal can be obtained by resampling of the vibration signal that has been sampled in the time domain. Therefore, the time domain transient signal...
A method for monitoring and diagnosis the gear fault according to instantaneous energy spectrum based on the newly developed empirical mode decomposition (EMD) scheme is presented. EMD can adaptively decompose the vibration signal into a series of zero mean oscillatory functions called intrinsic mode functions (IMFs). Hilbert transform can track the instantaneous amplitude and instantaneous frequency...
Varying speed machinery condition detection and fault diagnosis are more difficult due to non-stationary machine dynamics and vibration. A new approach to fault diagnosis of bearing under running up based on order tracking and Hilbert-Huang transform (HHT) is presented. The non-stationary vibration signals are transformed from the time domain transient signal to angle domain stationary one using order...
The order bi-cepstrum technique is introduced and applied effectively to gearbox faults diagnosis under run-up condition. This new method combines order tracking technique with bi-cepstrum analysis. The resampling signal can be obtained by resampling of the vibration signal that has been sampled in the time domain. Therefore, the time domain transient signal is changed into angle domain stationary...
A new approach to fault diagnosis of gear wear based on Teager-Huang transform is presented. This method is based on Empirical Mode Decomposition (EMD) and Teager Kaiser Energy Operator (TKEO) technique. EMD can adaptively decompose the vibration signal into a series of zero mean Amplitude Modulation-Frequency Modulation (AM-FM)Intrinsic Mode Functions (IMFs). TKEO can track the instantaneous amplitude...
In order to process the non-stationary vibration signals during run-up of gearbox, the method based on angle domain average and autoregressive spectrum analysis is presented. This new method combines angle domain average with angle domain average technique. Firstly, the vibration signal is sampled at constant time increments and then uses software to resample the data at constant angle increments...
The speed-up and speed-down of the gearbox are non-stationary process and the vibration signal can not be processed by traditional processing method. In order to process the non-stationary vibration signals such as speed-up or speed-down signals effectively, the order envelope analysis technique is presented. This new method combines order tracking technique with envelope spectrum analysis. Firstly,...
A novel method to fault diagnosis of gear crack based on empirical mode decomposition (EMD) and autoregressive (AR) spectrum is presented. This method can carry out empirical mode decomposition and extract feature information of different machine parts in condition monitoring and fault diagnosis of machinery. The main objective of empirical mode decomposition is to separate the time series data into...
The bi-cepstrum technique is presented based on bi-spectrum and cepstrum analysis. This new method combines bi-spectrum technique with cepstrum analysis. Firstly, in order to eliminate the noise effects, the bi-spectrum is calculated. Then the bi-spectrum is processed by bi-cepstrum technique. The experimental results show that bi-cepstrum technique can effectively diagnosis the faults of the gear.
This paper investigates the cost-effective ranges of gearbox ratios and power ratings of multibrid permanent-magnet (PM) wind generator systems by using a design optimization method. First, the analytical model of a multibrid wind turbine concept consisting of a single-stage gearbox and a three-phase radial-flux PM synchronous generator with a back-to-back power converter is presented. The design...
A new approach to fault diagnosis of gear crack based on ensemble empirical mode decomposition (EEMD) and Hilbert-Huang transform (HHT) technique is presented. Firstly, the time-domain vibration signal of the gearbox with gear crack fault is measured. Then the original vibration signal is separated into intrinsic oscillation modes, using the ensemble empirical mode decomposition. Secondly, Hilbert...
Run-up and run-down are of particular interest in condition monitoring of gearbox as they highlight many unobservable system faults. However, varying speed machinery faults detection is fraught with difficulties due to non-stationary machine vibration. Fixed time sampling cannot cope with the varying rotational frequency of the machine, resulting in increasing leakage error and spectral smearing....
The order bi-cepstrum technique is introduced and applied effectively to gearbox faults diagnosis under run-up condition. This new method combines order tracking technique with bi-cepstrum analysis. The resampling signal can be obtained by resampling of the vibration signal that has been sampled in the time domain. Therefore, the time domain transient signal is changed into angle domain stationary...
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