Research On Dynamic Calibration Equipment For Small-force Thrust Measuring System

The development of modern measuring technology has achieved more and more improved measuring methods. Among them, research on measuring of small-force thrust has received much attention and endeavor, of which precision and dynamic characteristic are crucial points. The engine of attitude and orbit rocket belongs to this category, and study of the measurement of its thrust is one vital chain of the cause and research of China's aeronautics and space.This paper introduces a thrust measuring system for small-force thrust rocket invented independently. It adopts the principle of piezoelectricity quartz force measuring system, and measures the force value via multi-functional force measuring device. Illustrates the main job of the paper, which is to develop a dynamic calibrating device designed for the measuring system. For the dynamic calibration on the measuring system, a dynamic force signal is required to be applied to the system which equivalents to the signal generated during a real engine propulsion. Based on this requirement, the paper adopts the principle of electromagnetic force appears on coil in the magnetic field, introduces electronic vibration exciter as the executor and realizes desirable dynamic force signal with corresponding signal generator and power amplifier. Piezoelectric accelerometer is used as standard force sensor to acquire dynamic force signal. It put forward an idea of overcoming the interference to vibrator force signal sent off by the vibration exciter itself by means of theoretical analysis and Multisim simulation. Selects non-standard trapezoidal voltage signal as the source signal of the vibration exciter in place of the standard trapezoidal voltage signal in order to make the vibration exciter to output desired standard trapezoidal dynamic force signal. Signal generator has AT89S51 as its core, supplemented by D/A converter, LED, buttons and other components, as well as relevant programs designed to generate required source signal.Result of experiments shows that the measuring system for engine propulsion is in good operation, and the design principle of the trapezoidal dynamic force generator required for the dynamic calibration is feasible. Trapezoidal dynamic force signal acquired from designed device meet the requirement of dynamic calibration, which lays a firm foundation for the dynamic measuring on the engine propulsion.