| Missile has become an important military strategic weapon in modern countries.The missile can accurately hit the target rely on missile-borne computer,which is the control core of missile.Therefore,the performance,precision and stability of the missile-borne computer must be tested prior to launching the missile.Due to the large production quantity and complex internal structure of the missile-borne computer,the standard manual testing method is time-consuming,labor-intensive and expensive,which cannot meet the requirements of large-scale testing at this stage.To solve this problem,this thesis studies an automatic testing system to achieve the missile-borne computer test.The specific research content as follows:First,by analyzing the function and performance indicators of the missile-borne computer analog quantity acquisition system.The signals to be tested are divided into three categories according to the modules,including analogue quantity input and output modules,switch quantity input and output modules,and communication test modules.A comprehensive system diagram is proposed depending on the functional requirements of the system.The system is composed of computer control software,hardware circuit system and test cables.Operational amplifiers,analog switches,ADC and other devices on its accuracy is analyzed emphatically to improve the accuracy of the system acquisition.Secondly,selection and design of the key module and key chip of the hardware circuit are completed,which are mainly divided into the selection and design of the computer core board module and the hardware peripheral circuit with FPGA as the control core.The hardware circuit includes voltage follower circuit,multiplexer circuit,reference power circuit,ADC and DAC conversion circuit,serial port level conversion circuit,self-check circuit,tested product protection circuit,1553 B interface circuit and PCIE interface circuit,etc.It bring out the function of each module of analog quantity,digital quantity,serial port and 1553 B,as well as the self-test and protection requirements of each module of the system,and implement the data communication between PC and FPGA through PCIE bus.A filter circuit is designed for interference from power noise,digital signal and analogue signal.Then,addressing the issue that the hardware circuit cannot completely filter system noise,methods of wavelet thresholds denoising and adaptive filtering methods are applied for this research.The results of shows that there is random interference noise in the signal,the adaptive noise cancellation system can continuously update the weights according to the environmental changes to achieve better filtering effect.Consequently,the logical design of the ADC interface module,LMS/LMF filter module and data transmission interface module is completed on the FPGA side.The PC-side software using the idea of layering and modularization,which is divided into a main process and a real-time sub-process.The main process performs control and data display,and the RTX real-time sub-process is responsible for real-time reading of data.The application layer software is divided into self-check,detection,measurement,and user management modules,which realizes the reading,writing and control of each module driver.Finally,the hardware circuit is debugged and installed,and the system test platform is built.The power supply,analog input and output,and switch input and output of the system are measured.After the measurement data is qualified,the system is self-checked,and the test of the missile-borne computer will be carried out after the self test passes.The design of the automatic test software interface is concise and clear,which help testers to test products automatically with one click according to the interface prompts.The test results show that the system can quickly complete all its function on self-check,detection function and performance test.In addition,the system is stable,safe and reliable,and meets the expected goal at the beginning of the design. |
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