Research On High Precision Analogue Unit Of Flight Control Computer Based On FPGA

As the core unit of the UAV flight control system,the flight control computer completes the flight control and management of UAV.In order to get airborne sensor signal types of information,such as signal overload,angle of attack,altitude and airspeed,change speed and high accuracy requirements,a new type of flight control computer needs a real-time data acquisition unit with high precision.Therefore,the research on highly precision analog unit of flight control computer is carried out.Firstly,according to the flight control computer in the flight control system of the status,function and performance index,this paper puts forward the related functions of the flight computer simulation unit and performance requirements,and establishes specific research objectives.By analyzing the data acquisition accuracy,influencing factors,types of interference,characteristics and so on,the paper completes the overall design of the scheme of high precision analog input / output unit based on FPGA.Secondly,according to the design scheme,the system is decomposed into function modules which are independent of each other on the hardware,while are coordinated in function.In order to meet the requirements of high speed and high precision of data acquisition,the hardware circuit of anti EMI is designed,and the hardware system is designed and developed in detail.In order to improve the performance of electromagnetic interference,thermal noise and so on,through the Fourier transform correlation theory,the dynamic performance and spectrum characteristics of the acquisition signal are analyzed,and the main interference source characteristics are obtained.According to the analysis results of interference characteristics,the FIR digital filter is designed by using distributed algorithm,and the accuracy of data acquisition is further improved.At the same time,the analog unit drive software and data acquisition and processing software are designed and developed,and the software is embedded into the flight control software to verify the function of the software.Finally,this paper makes an experimental test and analysis for the functions and performance of each module in the analog interface unit,and tests the data acquisition precision of analog input and output module.The test results show that effective sampling accuracy of analog input is 14 bits and the resolution ratio of analog output is 16 bits of analog interface unit.Through the semi physical simulation platform,the flight simulation tests,display software and control software through the flight path,verifying the analog input and output unit of function and performance,the performance of the unit in the communication reliability,real-time etc.The experimental results show that this unit can meet the requirements of new flight control computer analog input and output functions and performance requirements.