Papers by Keyword: Rotating Machinery

Abstract: Rotating parts such as shafts, gear wheels, ball bearings or rollers are subject to wear that limits their life cycle. Damage causes loss of production and consequential damage to the entire production plant. Based on the application in a support roller, a system design is presented with which it is possible to record and wirelessly transmit relevant measured values in or on rotating machines without an additional voltage source. The system is largely maintenance-free and can be implemented with components that are currently freely available on the market.

Abstract: Rough set theory is a useful tool for attribute reduction of fault diagnosis for rotating machinery, but cannot be efficiently used to sample increased areas. Aiming at the problem of incremental attribute reduction, a novel attribute reduction algorithm was put forward based on the binary resolution matrix for the two updating situations and the algorithm had a low space complex. Finally, with the fault diagnosis experiments of the bearing, the attribute reduction method was proved to be correct.

Abstract: Trouble-free operation of large-scale mechanical equipment is of great significance to modern industrial production. The existing wireless sensor network nodes are not suitable for condition monitoring of mechanical equipment due to their low acquisition accuracy. In view of this, this article put forward a wireless sensor network for mechanical condition monitoring, and designed corresponding wireless sensor network nodes. These nodes could achieve high-precision acquisition of analog signals. This article described a wireless sensor network structure for mechanical condition monitoring, hardware design of wireless sensor nodes and software design of the system. The precision of the wireless sensor network nodes we designed was verified by experiment. The experiment result showed that the nodes could effectively acquire analog signal with high precision.

Abstract: Rotation machine plays an important role in the production of electric power, chemical industry etc... In the methods of fault diagnosis, the selection of the Pc and Pm of common genetic algorithm will influence its convergence and is easy to be trapped into the local optimum to propose an adaptive genetic algorithm of the fault diagnosis; and in the implementation of system function, it takes the S3C2410 chip as the core of the microprocessor and uses the embedded Linux as the operating system as the software development platform. In this paper ,it introduces the design of the various parts of the system hardware in details, achieves the Boot Loader through combination of the hardware platform and successfully transplants the Linux operating system and builds a root file system, with the combination of the Linux operating system platform, it achieves the LCD frame buffer display device frame buffer, touchscreen A/D converter and development of Ethernet driver program, and the develops the data acquisition, wavelet packet analysis and Ethernet driver program etc. based on the system functions.

Abstract: BP neural network has a good nonlinear mapping ability, and can describe the relationship between frequency characteristics and fault. However, the multi-resolution wavelet neural network has the simple learning rules, fast training speed with the avoidance of local minima. So a multi-resolution wavelet neural network based on UKF is proposed to solve the problem of fault diagnosis for rotating machinery. The simulation result shows that the proposed multi-resolution wavelet neural network based on UKF value has a good diagnosis capability, and is better than that of traditional BP neural network and wavelet neural network.

Abstract: Rubs between stator and rotor are the most common and destructive faults in starting or running of rotating machinery. Force of radial rubs is the main parts of rubbing system dynamic models, and determines their accuracy directly. Force model is very important for fault diagnosis in theories and its applications. The recent studies on force models of radial rubs are introduced. Their modeling theories and its applications are summarized. The used conditions and applications scopes are analyzed mainly. The advantages and disadvantages of different models are discussed. It is pointed out that describing rubbing force accurately and building useful models will be the future studies, based on rational theories, considering environment factors, choosing all kinds of parameters affected to models.

Abstract: Large rotating machinery is widely used in industrial production process. With the computer network technology, system testing technology, signal analysis and fault diagnosis technology, large motor based on high speed wire rod production line as the object, the online monitoring method of large motor is present. Based on it, the signal processing approach of large motor under complex circumstance is proposed, and the software of on-line monitoring system for large motor is developed. Through monitoring the key parameters of the distributed signals of temperature, pressure, current and so on, the developed system can accurately analyze and locate critical faults of equipments, reduce faults rate, extend the service life and increase productivity of the motor equipment.

Abstract: The paper presents results of the active diagnostics experiments on influence of fatigue metal damage of the inner race of bearing and unbalance of rotating masses on vibration generated by the machine. Analysis of vibration related phenomena is a solution commonly applied in Structural Health Monitoring (SHM) systems. The application of vibroacoustics methods for technical condition monitoring has been developed in the past years in many systems of manufacturing processes. Vibroacoustic methods, based on the analysis of vibration or acoustic signals perceived as residual processes of non-invasive nature, is becoming more and more important in this respect. The scope of its application as well as the applicability of methods in numerous diagnostic systems also results from the capabilities of advanced methods of signal analysis and identification of numerous characteristics of technical condition. One of the most common operation damages are caused by rolling bearings wear. The scope of research contains tests on bearing damage and the unbalance of disc. The wear processes and unbalance are closely related to the vibration levels (arising from the mass loss of plastic deformation, and the fatigue damage). The research was conducted on special research test bench for vibration monitoring for rotating machinery. Structural health monitoring of machinery has to be conducted in different states and working conditions of the manufacturing system. Thus for simulating of different operating conditions the experiments have been conducted during run up of the machine which consist the transient states of working and during work on constant rotational speed of the power generate engine. For the identification of the symptoms of the machinery and equipments health monitoring the vibration signal have been analysed in time domain and frequency transformation as well. The performed signals are not stationary. Thus it is better to observe the signal simultaneously in time and frequency domains. For this purpose the spectrograms were determined. Spectrograms computes the short-time Fourier transform of a signal by default divided into segments. During the transformation the Hamming window and noverlap were used. For the comparison of the vibration of good and damage bearings signals registered for different frequencies have been presented in form of spectrograms and RMS distributions.

Abstract: The running speed of rotating machinery will have a negative influence on the quality of acquired data used in fault diagnosis. Poor-quality signal may cause misinterpretation of monitoring system, and even lead to the false alarms or failure of detection. To improve the quality of the signal and enhance the accuracy of the fault monitoring system, a novel automatic tracking filter for data acquisition based on FPGA was developed. This newly developed filter can adjust to its real-time cut-off frequency relying on the detected rotational speed. Moreover, the introduction of the Ping-Pong operation realized the non-disturbance shifting of output data. The results obtained from the simulated and pragmatic experiments revealed that this filter could achieve automatic tracking for rotational speed and ameliorate the quality of sampling signal utilized in fault diagnosis.

Abstract: The paper examines the issues of improving the rotor units by means of using support units with actively changeable characteristics. An overview of the known solutions related to the use of active bearings in various types of turbomachinery is provided. A closer look is given at the design and features of active radial bearings, the main elements of which are fluid film bearings. The results of mathematical modeling of active hybrid bearings are presented. The prospects of the use of this type of supports to improve the dynamic characteristics of rotating machinery, including reducing vibrations caused by various factors, are analyzed. Promising directions of development of active bearings are considered, which primarily involves the modification of system components and rotor motion control system algorithms, including intelligent technologies and artificial intelligence methods.