Development Of Pulsating Thrust Measuring System Of Attitude-control Rocket Engine

As an important component of modern space vehicles, attitude-control rocket engine has been widely applied in space shuttle, spacecraft, interceptor, satellite and multilevel launch vehicle. It plays a main role in orbit control, attitude adjustment, and terminal velocity correction, etc. The accurate measurement of pulse thrust of attitude control rocket engine has very important significance for deviation rectification and attitude adjusting of space vehicle. It not only can make aircraft be adjusted to appropriate attitude accurately and promptly, but also can avoid fuel waste which is caused by repeated adjustment.According to the characteristics and the measurement requirements of a certain type of attitude-control rocket engine, considering the excellent characteristics of piezoelectric quartz force sensor on the dynamic force measurement, a piezoelectric quartz thrust-measuring platform is deigned. Two groups of symmetrical piezoelectric quartz crystal wafers are used as the core of thrust-measuring platform, and the thrust is measured by using three pair yx crystal wafers in the each group to measure force of shear direction. Through this method, the sensitivity of thrust-measuring platform is increased, and the measurement of small thrust is realized. Based on the piezoelectric quartz thust-measuring platform, a suit of static calibration apparatus of small-power rocket motor thrust measurement is established. The problem of hydraulic load is solved. The stiffness of the elastic ring of thrust-measuring platform is calculated with analytical method and finite element method. The validity of the finite element method is justified by theoretical calculation. The calculational results of the two methods are testified by experiment. In order to raise the sensitivity of thrust-measuring platform, the parameters of the elastic ring are chosen by analyzing its stiffness and natural frequency. The static indexes of the thrust-measuring platform are acquired by experiment. The uncertainty of the static calibrating system is evaluated.The experimental results indicate that the piezoelectric quartz thrust-measuring platform has good performance. Its linearity and repeatability are all less than 0.5% and resolution is 50 mN with uncertainty of less than 2%. Therefore, the thrust-measuring platform can be calibrated by the static calibrating system, and its static indexes all can satisfy the requirements of measurement of small thrust attitude-control rocket engine.