Design Of Multi-Point Vibration Singnal Acquisition And Analysis System

With the shortage of terrestrial resources and the need to obtain more resources to meet the rapid economic development,countries around the world have turned their attention to the oceans with abundant resources and limited exploitation.Ships are essential for the exploitation of marine resources,and their normal navigation is a top priority.Ship vibration is one of the key factors affecting the normal navigation of the ship.It not only shortens the life of the ship,but also affects the working life of personnel and instruments on board.It has become a problem that cannot be ignored.Therefore,the collection and analysis of vibration signals is of great practical significance.In this paper,a multi-point vibration signal acquisition and analysis system is designed for structural vibration problems.The system uses a 24-bit A/D chip to accurately collect vibration signals from multiple points to be measured.The collected data is transmitted to the upper computer through the Ethernet line in the TCP/IP protocol,and the analysis result is processed,stored and displayed in real time in the upper computer.The main contents of the thesis include the overall system design,hardware platform development and supporting software development.According to different functions,the system hardware platform is divided into signal conditioning unit and signal conversion unit,and the two units can be divided into multiple modules.The channel switching module may select an acquisition signal or a system self-test signal to access the signal conditioning module;the signal conditioning module can amplify the input signal at multiple levels,and its gain can be adjusted;the analog-to-digital conversion module uses AD7768 as the A/D chip to acquire the eight-channel signal synchronously;the data buffer module uses two pieces of RAM to form a ping-pong structure for data access;the digital control module uses Cyclone III series FPGA(EP3C16Q240C8)as the control core,which is mainly responsible for controlling the amplification gain of the signal,the data acquisition of the A/D,the data access of the RAM,and communication with the host computer through the network interface module;the signal generation module is responsible for the generation of the self-test signal.The system software part includes program development of each hardware module and the host computer display and control interface.The display and control interface has the functions of system self-test,changing the amplification gain,etc.In the test process,the data can be observed and saved in real time through the display and control interface.Finally,a number of tests and vibration tests are performed on the system to verify the system’s function and performance.The results show that the system implements all the predetermined functions,and the operation is stable and the number of terminals is expandable.The transmission rate is greater than 1.3MB/s,and the equivalent input noise of each channel is less than 3μV.The amplitude uniformity is better than ±0.2dB and the phase consistency is better than ±0.3° in the frequency range of 5Hz~20kHz,which satisfies the system design requirements.In the vibration test,the system’s acquisition results are consistent with those collected by B&K equipment.