Precision Analysis Of In-bore Velocity Measurement And High Precision Control Of Mazzle Velocity For Eletromagnetic Launch

In recent years,due to its high initial velocity,good controllability,strong security and other advantages,electromagnetic launcher has shown great potential in military and scientific research.With the development of electromagnetic launch technology and the gradual improvement of precision strike requirements for launching device,the accurate measurement and control of armature in-bore velocity is particularly important.In this paper,the electromagnetic launch system and B-dot probe are modeled,the armature velocity measurement accuracy based on B-dot probe is analyzed,and the method to improve the measurement accuracy of B-dot probe is proposed.A multi-stage armature velocity closed-loop control strategy is designed to improve the accuracy of armature muzzle velocity.The effectiveness of the multi-stage closed-loop control method is verified by comparing the armature muzzle velocity of open-loop and multi-stage closed-loop experiments.The main contents of this paper are as follows:Firstly,the model of electromagnetic launch velocity measurement system based on B-dot probe is established.By setting the parameters of charging voltage,initial preload,discharge time sequence,penetration depth and rail length,combined with electromagnetic launch system model and B-dot probe model,the displacement time curve and velocity displacement curve of armature in in-bores are obtained,and compared with the test curve to verify the accuracy of the established model.Secondly,in order to analyze the velocity measurement accuracy of the B-dot probe array,combined with the mathematical model and simulation software of the B-dot probe array,the factors affecting the velocity measurement accuracy of the armature are analyzed.The principal component analysis method is used to get the main influencing factors and the corresponding optimization method is proposed.The Douglas puck algorithm is used to get the distribution position of the B-dot probe array,which improves the velocity measurement accuracy of the B-dot probe array The proposed optimization method is verified by the actual launch test.Finally,in order to improve the accuracy of armature muzzle velocity,the influence of discharge timing on armature muzzle velocity is analyzed,and a multi-stage closed-loop control method based on discharge timing is proposed.The experimental results show that the initial velocity of armature can reach 0.53%,which is 0.48% higher than the accuracy of open-loop launch mode of 1.01%.The effectiveness of the proposed multi-stage closed-loop control method is verified,which has important guiding significance for the high-performance application of electromagnetic rail launch.