Study For Monitoring The Vibration Of Large-scale Wind Tunnel Unit Base On Intelligent Sensor Array

With the development of pace of life and modern mechanical engineering technology, speed of large-scale moving machinery become faster and faster, and the efficiency of the mechanical system is improved a lot. But as a result, vibration hazards become a serious problem. Therefore, condition monitoring and fault diagnosis technology of large-scale mechanical equipment have gotten more and more attention. The mechanical vibration is an important characteristic parameter of the operation of mechanical equipment. Mechanical vibration monitoring is an important means of mechanical equipment condition monitoring and fault diagnosis. Studies have shown that: In some area of vibration monitoring to large-scale machinery and equipment (such as a large wind tunnel unit), existing mechanical vibration monitoring methods cannot meet the needs of large dynamic range monitoring of large-scale mechanical equipment. It mainly has the following shortcomings: single monitoring point, small dynamic range of the monitoring system, rigid communication mode and so on. These seriously affect the reliability of mechanical equipment condition monitoring and fault diagnosis. At present, vibration monitoring of large-scale and complex mechanical equipment has become the frontier of the field of mechanical equipment condition monitoring and fault diagnosis.Based on intensive study of existing mechanical vibration monitoring technology and communication theory, combining with the specific application environments in the field of large-scale and complex mechanical vibration monitoring area, a“multi-point-multi-parameter”remote vibration monitoring program for large-scale mechanical has been proposed, and the vibration sensor array model based on multi-sensor management has been built in this paper. We studied on the communication model, which is combined wireless sensor network with mobile communication network, internet and low voltage power line communication network for mechanical vibration remote monitoring. And also we do the research on the application of suitable multi-source information fusion model in“multi-point-multi-parameter”remote monitoring for mechanical vibration. Then, a new method of vibration remote monitoring of large-scale and complex mechanical equipment has been explored. Based on our research works, it is expected to completely change the status of mechanical vibration monitoring, the real-time、accuracy and reliability of mechanical vibration monitoring can be improved and the provide the scientific basis for the mechanical engineering design and mechanical equipment fault diagnosis. It has important theoretical value and practical significance to the improvement of the theoretical level and application level of mechanical vibration monitoring in China.Main research works are listed as follows:(1)For the all-round vibration status monitoring of large-scale mechanical equipment, a“multi-point-multi-parameter”monitoring program has been proposed.Generally in the existing mechanical vibration monitoring technology, a representative part of the vibration body is chosen as a monitoring point that is installed with the vibration sensors to implement the vibration monitoring. But this is only suitable for the simple mechanical equipment. For the large-scale and complex mechanical equipment, the vibration status of different parts and different positions of the same part is different. And the result of single point monitoring cannot fully reflect the vibration status of the objects. So, this“single point of monitoring”mode is far from meeting the needs of vibration monitoring and fault diagnosis for large-scale and complex mechanical equipment. Hence, the“multi-point-multi-parameter”mode has been proposed in which the monitoring points are arranged respectively at different parts and different positions of the same part. Through the vibration sensors from multiple monitoring points, it will all-round monitor the vibration characteristics of mechanical equipment simultaneously, then multi-sensor management technology and information fusion technology have been used to integrate the measured information, and at last, the statistical vibration characteristics of monitoring objects can be obtained. It provides reliable statistical data for vibration monitoring and fault diagnosis for large-scale mechanical equipment.(2)To determine the multiple monitoring points of“multi-point monitoring”, a program of mechanical vibration features extraction and monitoring points layout based on finite element analysis has been proposed.Because of the complexity of vibration status of large-scale mechanical equipment, the determination of monitoring points is so important that it will brings serious consequence if there is something wrong with it. Therefore, the selection and arrangement of monitoring points is the key point of the issue. All kinds of factors that will affect working conditions of equipment should be considered, and especially in the case that simulate the vibration status under extreme conditions. The finite element analysis need to be applied based on the geometric parameters and working load parameters of monitoring objects to get the basic vibration characteristics and then determine the layout points.The performance of vibration sensor is the key issue should be considered firstly in mechanical vibration monitoring. Generally, traditional sensors can only fulfill the conversion between non-electricity and electricity, and there are many shortcomings and inconvenience, such as weak signals, low sensitivity and nonlinear error. Especially when we monitor multiple parameters simultaneously, multiple sensors will be needed, and the traditional collection system is too complex. For this, we used mini-sensors as the array elements, and made the lots of mini-sensors of different function to construct an“array”. Then we integrated the array with the shared array managers, signal processing circuit and intelligent chip to form the multifunctional sensor component with primary intelligent, and it is called intelligent sensor array.(3)To achieve the reliability transimission of the system, a redaunt monitoring communication model based on both the baseband transimission and the band transmission has been proposed.Wired mechanical vibration monitoring system has been widely used, but it has shortcomings such as: complex wiring, higher deployment costs, poor maintainability and scalability. Therefore, mechanical vibration monitoring system based on wireless sensor network has emerged, and it brings new vitality to the wireless monitoring mode for mechanical vibration. However, the security、reliability、communication distance and the power limited issues of these systems are challenging.For this, after we deeply studied on the existing communication technique and made full use of its network resource, a remote monitoring communication program integrated of Wireless Sensor Network, General Packet Radio Service, Internet and Power Line Communication has been proposed. It is used as a supplement so that both the baseband transimission and the band transimission can be used in the monitoring system.(4)In order to improve the monitoring efficiency and reduce network overhead (especially energy costs), the distributed data fusion algorithm for mechanical vibration network has been proposed.On the one hand, the sampling frequency required by mechanical vibration monitoring is usually among 1 kHz~10 kHz, and lots of vibration data will be generated by the high-frequency sampling. On the other hand, because of using“multi-point-multi-parameter”mode there will be multiple sensors at one monitoring point, and as a result, the monitoring data will be into a massive growth. To minimize network overhead, avoid congestion and ensure reliable transmission of information, the multi-grade data fusion technology need to be used, so that the efficient operation of multi-point-multi-parameter remote monitoring network for mechanical vibration can be achieved.(5)Design and implementation of the multi-point-multi-parameter remote monitoring system for mechanical vibration.Based on completion of above research works, the "multi-point-multi-parameter remote monitoring system" model has been constructed and the remote monitoring experimental platform based on this model for mechanical vibration has been developed. Also, a lot experiments has been carried out to demonstrate the basic performance and practical application of the system. Experimental results have demonstrated the feasibility and advancement of the mechanical vibration monitoring system. The system can be widely used in the mechanical vibration monitoring of kinds of large-scale and complex machinery and equipment, and also can be applied to the area of monitoring health status of large-scale equipments.The end of the paper is the summary of research works and prospects for future research.