| Microseismic monitoring technique is widely used in production and construction.Vibration signal acquisition and data transmission are important links in microvibration measurement.Signal quality,frequency range,data accuracy and other factors in the measurement process have great influence on the location and analysis of micro-vibration events.At present,the equipment used for microseismic monitoring mainly relies on foreign imports,which are expensive,bulky and complicated to install.In order to meet the wireless acquisition requirements of vibration data and adapt to a variety of application environments,this thesis carried out the development and research of the TCMNI(three-component microseismic node instrument)based on ZigBee/WIFI/LTE Cat.1 wireless transmission modes.The main contents of this thesis are as follows:(1)The realization of microseismic data acquisition function of the system.The frequency of microseismic signal is low.The natural frequency of commonly used moving coil sensor is above 5Hz.In order to reduce the natural frequency of the sensor without changing its mechanical structure,it is necessary to compensate the low frequency.In order to reduce the minimum frequency that can be collected by the system,a frequency compensation circuit was added to the system.And the circuit system function matched with the geophone system function by optimizing the circuit parameters.The system signal conversion needs to meet the characteristics of high dynamic range,wide frequency band,high signal-to-noise ratio and high precision.After comparative analysis,the system uses ADS 1282 analog-to-digital conversion chip produced by TI company to improve the signal fidelity and resolution of the system.(2)The realization of positioning function of the system.GPS positioning system is the main positioning means used by most vibration testing equipment and seismic exploration equipment at home and abroad.GPS positioning system is easy to be affected by the environment and in many harsh environments GPS signals cannot be received.In addition to GPS positioning System,this System adds BDS(BeiDou Navigation Satellite System)positioning System and ZigBee-based wireless ranging positioning mode.Through a variety of positioning mode optional design scheme,to achieve node instrument positioning requirements in different scenarios.(3)The realization of data transmission function of the system.The system uses three network forms including wireless cellular Internet of Things,wireless local area network and wireless heterogeneous network.Users can select the data transmission mode based on the application scenario.The wireless cellular Internet of Things of this system is realized by the cellular Internet of Things module based on LTE CAT.1,which makes use of the existing carrier network and has the characteristics of wide coverage and high stability.Wireless LAN with 802.1 lb/G/N module can easily access WIFI wireless network.A wireless heterogeneous network is realized by the combination of CC2530 kernel ZigBee module and WIFI module.Through the above three wireless transmission design scheme,the system has a variety of wireless transmission modes,the node instrument developed has the characteristics of suitable for a variety of scenarios.(4)The specific design and the implementation of the system.According to the functional requirements of the system to design the overall scheme of the system,divided into specific functional units.Based on the overall scheme of the system,the hardware circuit design of each functional unit is completed,including device selection,circuit principle design,Printed circuit board(PCB)design and production and debugging of physical objects.On the basis of system hardware,the design of each module subroutine and system running main program is completed.Finally,the function of the system is tested and verified to confirm the feasibility of the system scheme.The wireless TCMNI developed in this thesis can greatly reduce the cost of equipment because of the use of general electronic components and independent design of software scheme.The system is powered by lithium battery,with compact circuit design and small volume.At the same time,the system adopts a variety of positioning methods and wireless data transmission methods,which can reduce the complexity of equipment installation.The system has various functions,wide application range,flexible and convenient use. |
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