Research On Thrust Vector Measurement System For A Lunar Soft-landing Rocket Motor

Aerospace technology has always been an important symbol of the national scientific and technology development level. Entering the new century, our country have introduced a series of deep space exploration, such as lunar exploration mission of Chang’e project and mars exploration program. Deep space exploration gives a higher request to the performance of the rocket motor. As the key performance parameters of rocket motor, thrust vector is significant in the aircraft attitude control and control precision. How to measure the thrust vector produced by the ignition of the rocket motor has became an important problem to be solved at present. The traditional thrust test system cannot meet the requirements of thrust vector measurement. Developing a set of measuring system for precisely assess the thrust vector produced by rocket motor, has important scientific significance.This paper takes the thrust vector measurement of a lunar soft-landing rocket motor as research object. The aim is to realize the accurate measurement of thrust vector. Using the outstanding research achievement of six dimensional force piezoelectric dynamometer, verified the feasibility of thrust vector measurement from thrust parameter definition, mathematical modeling, formula derivation, etc. A thrust vector measurement system based on a dynamometer with for piezoelectric quartz sensors has been developed for lunar soft-landing rocket motor. The thrust vector measuring system is made up of4three-component piezoelectric force sensor. The thrust vector produced by rocket motor can be calculated by the12output signals. Then the magnitude, direction, and location of thrust vector can be specified. According to technical requirements and accuracy parameters of thrust vector measuring, calibration device is designed. Hydraulic pressure force generator combined with standard force sensor is adopted by calibration system. The main force calibration device is mounted at the back side of the piezoelectric dynamometer. A self-centering device is designed to improve the defect of the main force calibration device. In order to simulate the thrust vector produced by the rocket motor, a deflecting force generator is designed based on the mechanical structure of main force calibration device. The deflecting force generator implements the thrust vector calibration. According to different calibration conditions, carried out comprehensive calibration test, such as system calibration and calibration in working condition. Throughout the development process, a large amount of calibration test and comparison test is carried out. Data processing is implemented to the thrust vector measuring system and acquired the performance parameters of the system. The calibration test and analyzes of calibration results show that the thrust vector measuring system of rocket motor has excellent property. The test principle for thrust vector measuring system is correct, and the result of the calibration test has attained the anticipant goals. The performance parameters of the measurement system meet the requirements of thrust vector test.