Space Debris Impact Spacecraft Location Algorithm And System Integration Based On PVDF

With the speed of human exploration and utilization of space,the amount of space debris is increasing day by day,threatening the safety of spacecraft in orbit.When the space debris hits the spacecraft bulkhead,it will lead to the decline of the strength of the spacecraft structure,and in serious cases,it will form a hole and cause gas leakage,endangering the life of astronauts.Therefore,it is of great significance to determine the location of the impact source in time and accurately for evaluating the safety of the spacecraft in orbit and ensuring the life safety of the astronauts.Among the positioning methods of space debris impact spacecraft,PVDF detection method has the advantages of flexible use,light weight and suitable for harsh environment,so it has become an important development direction in this field.First,the space debris impact simulation experiment system and the impact point positioning test system were constructed.The PVDF circular film sensor was used to build a lightweight sensor array.The two-stage light gas gun system was used to load the projectile impact 2A12 aluminum alloy plate at hyperspeed,and the characteristics of the hyperspeed impact signal were obtained and analyzed to provide parameters for the subsequent impact source location.The influence of the diameter of PVDF circular thin film sensor and the radius of sensor array on the positioning effect was analyzed by multiple hypervelocity impact experiments under different sensor arrangements.The results show that when the plate size is 400 mm×400 mm,the positioning error of impact point is less than 8 mm.Under the condition that the diameter of the PVDF circular film sensor is the same,the smaller the distance between the PVDF sensor array and the impact point,the higher the positioning accuracy.Under the condition that the distance between the PVDF sensor array and the impact point is the same,the larger the diameter of the PVDF circular film sensor,the higher the positioning accuracy.The finite element software ABAQUS was used to build a simulation model,and the impact of space debris on the 2A12 aluminum plate was simulated by the aluminum ball impacting the spacecraft at high speed.The stress wave propagation law in the target plate was studied.The results show that the numerical simulation is basically consistent with the experimental stress wave shape,and the arrival time and peak value of the first wave have little error with the experimental results,which lays a foundation for the subsequent optimization of the system.Lab VIEW graphic programming software was used to write the location sub-VI program,combined with NI data acquisition card and DAQ data acquisition module,the real-time location of space debris impact source integrated system was constructed.The integrated system for real-time location of space debris impact source can realize the setting of data acquisition card,waveform observation and display of location results on the human-computer interface.Aiming at the shortcomings of the traditional TOA triangle location algorithm,the BP neural network algorithm combined with numerical simulation was used to locate the impact source coordinates.The results show that the maximum positioning error of the BP neural network algorithm is less than 3 mm,and the positioning accuracy is twice that of the traditional TOA localization algorithm.In order to further improve the positioning accuracy,the layout parameters of the circular PVDF thin film sensor array were optimized by using genetic algorithm and numerical simulation.The results show that the genetic algorithm can improve the positioning accuracy effectively.