Research On Detection System For Rocket Compression Spring Stiffness

In recent years,China’s space industry has developed rapidly,and the density of launching rocket has become higher and higher,so the quality and performance of components in the rocket has become more and more important.Compression springs are widely used in rockets.The stiffness of spring has a significant impact in rocket.Improving the stiffness testing of compression springs in rockets is of great significance to the development of China’s space industry.The stiffness of compression springs usually fluctuates a lot in the elastic range and can’t satisfy the demand of rocket due to machining error or defects of materal which affects the safety of launching rockets.Therefore,it is necessary to test the stiffness characteristics of the rocket compression spring to eliminate the unqualified product.At present,the method of detecting the average stiffness within a certain compression amount is used,and the fluctuation of the stiffness within the complete deformation range of the spring cannot be obtained,which leaves a safety hazard.So,it is necessary to study the stiffness detection system of rocket compression spring stiffness to improve the quality and accuracy of the stiffness detection.According to the structural dimensions,stiffness characteristics and testing requirements of the three kind of springs to be tested,the specific indexes of the detection system are determined.According to the requirements of the system,the overall design of the detection system of rocket compression spring stiffness was completed.The design and construction of the mechanical structure of the system were carried out,including the loading mechanism,the positioning and clamping mechanism and the selection and layout of the sensor.The design and construction of the hardware circuit of the control system is completed using STM32F103ZET6 as the main control chip and AD7606 as the data acquisition chip.And the embedded program is written.Based on MFC,the development of PC software was completed,and the serial communication with STM32 and the control of the system were realized.The filtering algorithm for sensor signals is designed,and the filters of sensor signals are realized by MFC and Matlab joint programming.The design and construction of the system database was completed by using Access,which realized the storage and management of experimental information.The accuracy of the detection result is guaranteed by the calibration experiment of the laser displacement sensor and the simulation experiment of the filter.The evaluation index of spring eligibility was established,and the critical value of each index was got through a large number of experiments.Finally,the experiment of the system’s accuracy and experiment of the spring stiffness test were carried out,and the eligibility of springs was evaluated.The research on the detection system of rocket compression spring stiffness includes the design of the mechanical structure of the system,the design of the control system,the development of the PC software and the experiment of the system.The accuracy of spring stiffness detection is improved effectively and the technical requirements of the system are met.