Research On Remote Measurement And Control Technology Of Rocket Engine Based On Wireless Transmission

The traditional rocket engine test needs to lay a lot of cables,and the change of measuring points will cause problems such as equipment calibration,cable re routing and so on.With the rapid development of wireless communication technology,wireless communication has been gradually applied to industrial production,so the remote measurement and control system of rocket engine based on wireless transmission shows great advantages.In the wireless measurement and control system of rocket engine test,the data transmission delay will bring two problems.On the one hand,it will affect the propellant supply servo system,destroy the stability of the system,and then cause the test mission failure;On the other hand,in the process of rocket engine test,a large number of signals need to be collected with high speed.Once the time delay occurs,the data will accumulate,resulting in the data buffer full,and then data loss.This paper studies and analyzes these two problems respectively,and puts forward the corresponding solutions.The propellant supply system of the engine is a second-order system,which adopts the traditional PID control and is sensitive to time delay.In order to improve the stability of the system under random time delay,the mathematical model of the propellant supply system is established,and the internal model control and PID control are combined,The calculation formulas of single degree of freedom and two degree of freedom internal model PID controllers are given by formula derivation,and particle swarm optimization algorithm is introduced to find the optimal parameters of the two kinds of internal model controllers.In order to reduce the impact of data transmission delay on large data acquisition,the LZW dictionary compression algorithm is used to compress the collected data through the analysis of sensor historical data,so as to reduce the amount of data transmission.In order to further optimize the compression speed and compression ratio,some problems of traditional LZW algorithm are optimized,and the related design of software and hardware is carried out.In order to verify that the internal model PID control algorithm is feasible and effective for the control of time-delay system,a wireless measurement and control system platform is built to measure the total delay distribution of the whole servo system.According to the distribution,the fixed delay and random delay environments are simulated respectively.By comparing the step response of four kinds of internal model PID controller with and without PSO algorithm,single degree of freedom and two degree of freedom internal model PID controller,the feasibility of using PSO algorithm to find the optimal parameters of internal model PID controller is verified.It is proved that when the internal model does not match or even seriously mismatches,the two DOF internal model PID controller can still maintain the system stability,and the steady-state error is kept within 2% and no overshoot.It is proved that the two DOF internal model PID control optimized by PSO can effectively solve the transmission delay problem and has good robustness,and can be used as the controller design method of propellant supply system.In order to verify the performance of the data compression algorithm,the sensor historical data is compressed through the data compression unit,and the decompressed data is compared with the original data to verify the accuracy of the algorithm;The data of different sizes of the sensor TXT file are compressed separately,and the curves of compression ratio and compression time under LZW and the improved LZW algorithm are drawn.From the curve,it can be seen that the compression time of the improved LZW algorithm is about 1/3 lower than that of the traditional dictionary compression algorithm,and the compression ratio is basically stable at 1.7,which is about 0.2 higher than the dictionary compression algorithm before optimization,The compression performance of the algorithm is verified.