Design And Implementation Of Multi-Channel Vibration Data Acquisition System Based On Multiprocessor

Vibration data acquisition is an important part of equipment condition monitoring and its related control.The vibration signal reflects the state of the structure or equipment operation.By designing the vibration data acquisition system,the vibration signal is collected,and the results obtained by analyzing the vibration signal can be used as an important evaluation index for structural health monitoring or an important feedback variable for equipment control.The time-frequency characteristics of the vibration signal are studied,the feature information is extracted,and the dynamic displacement response is obtained by the method of the second integral of the vibration acceleration signal in the time domain.The acquisition system fully considers the advantages of FPGA and ARM,and adopts the multi-core architecture design scheme of FPGA and ARM.Considering the need to synchronously collect multiple sensors,the acquisition system has designed twelve synchronous acquisition interfaces,and through the configuration of the front-end analog circuits,the matching of different sensor access types is realized.The system adopts dual ADC design,and each ADC completes synchronous sampling for six channels,FPGA simultaneously controls the startup and conversion of the two ADCs to achieve simultaneous sampling of twelve channels;the communication between the acquisition system and the server or the host computer is realized by using the Ethernet interface to complete the realtime transmission of sampling data and the parameter setting of the acquisition system by the server.;taking into account the off-line working scene of the acquisition system,the local storage of sampling data in low-speed sampling mode is realized by using Micro SD card.;the RS485 interface of acquisition system can realize synchronization between multiple acquisition systems,hence distributed synchronization data collection system can be built.Through the method of hardware system verification after functional simulation,the design of each functional module inside the FPGA is completed.According to the control command word sent by the server,the FPGA constructs a parameter setting register inside the FPGA to realize the setting of parameters such as sampling mode and sampling rate.Based on the working timing of the ADC,the sampling control of the ADC is realized and the sampling data of the two ADCs is completed.Taking advantage of SDRAM,deep buffer design of sampled data is achieved by FPGA and SDRAM;and the high-speed data communication between FPGA and ARM is realized by constructing asynchronous FIFO.ARM uses a preemptive multitasking real-time operating system(RTOS)for multitasking management.Lightweight Internet Protocol(LwIP)is used to realize network communication between the acquisition system and the server;through the configuration of the ARM high-speed data interface FSMC,the reading of the asynchronous FIFO and the writing of the parameter register are completed;(FatFS)implements file reading and writing operations on the Micro SD card.The correctness,real-time and reliability of the function design of the acquisition system are verified by collecting standard signal sources.The superiority of Hilbert-Huang transform(HHT)algorithm in dynamic non-stationary data processing is verified by the acquired shaking table data,as well as the feasibility of reconstructing the displacement of the second integral in the acceleration time domain.The time-frequency characteristics and dynamic displacement response of the bridge under different traffic flow are analyzed by the collected vibration response data of the bridge,which provides important basis for bridge maintenance and early warning.